The Initial Edition Of This Manual Has Been Based On Previous Guidelines And: Fill & Download for Free

Disclaimer :All of the content I mentioned below has been my experience and understanding of the situation and I do not claim that this is the only way to do things. The purpose of this post is to give an idea on how I studied for AIIMS PG entrance exam. Also I am not getting paid by any institute or authors to promote them, this is an honest review of the material I used. Feel free to disagree with me totally!!(edit: I decided to add a section of FAQ at the end of this post based on the questions I received…so keep on contributing as questions/comments and I will keep on adding more to this article…the aim is to compile everything for your prep…what to study and HOW TO STUDY!)(the FAQ section has my approach to “smart study” in somewhat detail so even if that FAQ is not your question still give it a read because it might help you in some other way)(also the aim of this post is to connect to you as a fellow student so i have written it in a very informal way with a lot of “…”and ”!! “.)Credentials for answering the question :I joined AIIMS NEW DELHI as a MBBS Student in 2013 (All India Rank - 7).Completed my Internship during Jan 2018 to Dec 2018 period from AIIMS.Gave AIIMS PG entrance exam in November 2018 during my internship :RANK 152 ( the old pattern exam)Joined as a Non academic Junior Resident in AIIMS NEW DELHI in Department of Cardiac Radiology & Endovascular Intervention from January 2019( which I am continuing at the time of writing this post) .Gave AIIMS PG entrance again in may 2019 :RANK 26 (the new pattern exam)(For the exam pattern of AIIMS PG entrance and how to tackle the "new pattern" you can refer to another question that I have answered.)Komal Gupta's answer to What do you think about the new paper pattern introduced in the AIIMS PG entrance exam?Now on the topic of preparation :1.I joined DAMS (PG Medical Entrance Coaching Institute, NEET PG )during my pre-final year (from Jan 2016) in foundation batch2. I had joined DAMS and DBMCI ( Dr. Bhatia Medical Coaching Institute ) TND during my internship year (from Jan 2018)3. I was a MARROW(Gold standard for NEET PG & SS ) pro plan B user from July 2018 till may 20194. I had also joined various facebook groups by subject faculties5. I had attended separate classes by various faculties : including -Medicine lectures (10 days) by Dr. Thameem Saif (Welcome to Bright Medicos )Orthopedics lecture(2 days) by Dr. Apurv Mehra (Dr. Apurv Mehra )Ophthalmology lecture (3 days) by Dr. Utsav Bansal (SOCH | Dr. Utsav Bansal )Anatomy lecture (4 days) by Dr. Rajesh kaushal (HUMANANAT-ACADEMIA )6. I had a full subscription for Uptodate (Smarter Decisions. Better Care. ) (which all AIIMS UG & PG students get for free from the institute)(in case you don't know about Uptodate-- it's an online learning platform that is a point-of-care medical resource and is marketed as an evidence-based clinical resource... Envision it as Harrison - but on steroids...online + getting updates ASAP + has information on all the clinical subjects... But super expensive)7. I had a lot of review books and notes.8.I Read few topics which I could not find anywhere else from wikipedia (Wikipedia ) and Medscape (Today on Medscape )too(on a side note : I didn't pay for a lot of these resources or got them on a discount which was provided to me because of my performance in college professional exams)DO YOU NEED IT? ALL OF IT?NOI just mentioned what options I had.Looking back at it now I feel most of it was just to prevent FOMO.(Because FOMO during entrance preparation is a real thing. May be that one lecture or one book can stand between selection and taking another year drop. May be this, may be that, a lot of may be! )In reality i was a very very very very selective reader.And this along with my exam day strategy was what made my preparation "smart work" instead of hard work.(you can read my exam strategy in the article I mentioned above)HOW MANY MONTHS I PREPARED FOR?All the studying i did during 2018 (during internship) was very irregular and rare... But I attended all the lectures and TND that i needed during that time and made good notes so that when I start my "serious" prep for may 2019 I have all the sources already available.Overall i gave it - 4 months of dedicated studyingWith January - February 2019 : focusing on 1st and 2nd year subjectsMarch - april 2019 : for revision of all 19 subjectsAnd I feel 4-6 months is enough time if you have a good understanding of your topics and have read from standard textbooks during your professional exams.You will need to give more time to cover up whatever deficit you have in your knowledge.So decide for yourself.Now...Coming to the actual point...WHAT AND HOW I STUDIED :(again mentioning that this is just my personal experience and we can agree to disagree here...)I studied only the important topics!How i knew what was important?I referred to previous year AIIMS PG question papers and marked all the topics from that subject that were asked previously into my review books even before I would start studying that subjectLogic behind it :1. 60 - 70 % questions in AIIMS are from repeat TOPICS (not saying questions are repeated though they are a lot of times, but the topics which are usually asked are almost consistent)2. Topper scores around 70%-80% marks usually3. No one knows answers to the weird and new and cool questions, not even the topper4. Everything "new" is either something that no one knows or an update to previous guidelines.5. I should know the strength and weakness of my enemy before I start preparing for the fight.6. I didn't want to read all the topics in all the chapters (!)Refer to previous 3 - 4 years of question papers (total 6-8 papers)(older questions based on older patterns and older guidelines are not needed... Also pattern changed a lot from November 2016 onwards and now again from may 2019)Now...The subjects...What I actually studied...ANATOMY :I attended Dr Ashwani's TND class (DBMCI) (Anatomy App by Dr. Ashwani Kumar ), it was really good.But i needed someone to teach me all that is needed for the exam once so that I don't have to read and get lost in anatomy on my ownI attended Dr. Rajesh kaushal 's class... It covered anatomy very well... Almost 100%... If he didn't teach something in the class then I never tried to read it on my own to prevent myself from getting lost in anatomy.(but spoiler alert :class is boring and long... Because that's how anatomy is... He repeats every topic a million times in the class... Listen to it... Imprint it in your brain... Try to survive through it)Must do electron microscopy images of cell from grey's anatomy (41 edition)PHYSIOLOGY :Dr. Somman Manna's review bookFirst aid to step oneGraphs from Ganong review of physiologyALL THE FORMULAS!RBC, WBC and platelet count calculation as we did during 1st year practicalBIOCHEMISTRY :First aid to step oneFew topics from Dr. Rebecca james ' review like porphyria, glycogen disorders.List of all the enzymes affected by insulin and glucagonProtein, starch and ketone testsPATHOLOGY:First aid to step oneDr Devesh Mishra' s reviewIMAGES (in AIIMS images are not asked from any book... They just ask the most typical image from the Google image page... So I compiled screenshot of those... Also Google gives you many perspectives of the same image so that helps too)Blood transfusion protocolMICROBIOLOGY :Dr. Apurb Shastri's review bookTND notes of Dr. Shivika (DBMCI)First aid to step oneIMAGESParasitology life cyclesFORENSIC :Dr Magendran 's review book ( felt more colourful and readable than sumit seth... I didn't die of boredom while reading it!)PHARMACOLOGY :Dr. Gobind rai garg' s review bookALL THE FORMULAS!(I was told to read the new drugs that are approved from FDA in the previous year.. Just Google it and you will find the list.. I tried... Couldn't memorize even 1... So decided to take the risk of leaving that question if asked.. It wasn't asked)Make a lists of drugs safe & Contraindicated in renal disease, liver disease, pediatrics and pregnancyMechanism of action of all drugsList of drugs of choice for infectionsMEDICINE :Dr. Thameem 's notesKnow how to identify ECG, acid - base imbalance questionsSummary of Uptodate articlesNew topics and updates of latest CMDT .(refer to FAQ section to know more about CMDT)Emergency medicine from emergency medicine module on DAMS emedicoz app by Dr Naman (Emergency Medicine, AIIMS)Dr. Arvind' s notes (DAMS) for CVS examinationSURGERY :ATLS manual (10th edition) (just Google it and you will get the pdf)Few selective topics from Dr. Pritesh Singh' s review(in surgery in AIIMS hardly anything other than trauma is asked... So just read that in very much detail)DAMS DVT (for cannula, sutures & catheters etc)PSM :High yield biostatistics for USMLE 4th editionDAMS DVTMalaria, TB, HIVWhatever new disease is famous that yearUpdates that are added in the latest Parks textbookALL THE FORMULAS!OBS-GYNAEDr. Deepti Bahl's TND / regular batch notesUptodate summaryImagesPEDIATRICSDr Meenakshi Bothra's reviewNeonatal resuscitationI was told to read "AIIMS standard treatment protocol" (they are treatment protocol for all diseases which are published by AIIMS faculty, available on google for free download and also as a book), I didn't get time for it(New Born Baby )AIIMS pediatrics youtube channel ( you will find the video of Silverman score that was asked in November 2018 there)OPHTHALMOLOGYDr. Utsav bansal 's class(for the first time in MBBS i understood what was going on in that subject)IMAGES from GoogleORTHOPEDICSDr Apurv Mehra' s class /review bookImages of tests and x rays from GoogleENTRead the chapter on hearing assessment from Dr. Sakshi Arora's bookThe multiple versions of the image of mastoidectomyANESTHESIADr. Ajay Yadav 's book from dbmiMedscape ( Today on Medscape ) for reading how to do procedures - I read how to take bp, insert foley, ryles, rapid sequence intubation and arterial sampling.RADIOLOGYDr Sumer Sethi' s TND classImages from GooglePSYCHIATRYDr Praveen Tripathi 's reviewFirst aid to step oneDAMS DVTUptodateDERMATOLOGYDr Saurabh Jindal' s review bookDAMS DVTImages from GoogleMISCELLANEOUS STUFF/MUST DO1.PEP & Blood spill guidelines ( just Google "AIIMS blood spill protocol"... A pdf from AIIMS Jodhpur will appear... Read these 2 topics from it)(https://www.aiimsjodhpur.edu.in/quick%20docs/HIC%20FINAL%20MANUAL%20AIIMS%20JDH%202-1-2018.pdf )2.DAMS DVT slides (will cover most images, instruments, clinical stuff and updates )3. IF IT HAS BEEN ASKED IN AIIMS EXAM PREVIOUSLY THEN YOU MUST KNOW IT4. Keep your eyes and ears open during your postings and grab as much information as you can. Examining a patient is the best way of understanding a disease. With the recent trend in the exam of more clinical knowledge and procedures based questions attending postings sincerely will surely give you an advantage.Question practice :1. MUST SOLVE PREVIOUS YEAR AIIMS QUESTION PAPERS (I have done them 5 times till now and revise all the topics from it)2. Give 3 hour grand tests / CBT/CLT (whatever you would like to call it)... Make a strategy on how to attempt questions... Knowledge and information doesn't matter... Just know how to solve questions... Learn how to find answers by logic even when you have no idea about the question. To get knowledge use your books, don't rely on any question bank for that.(read FAQ section below for more on this)3.Know your weakness4. I have given a detailed plan on how to manage time during the exam in the article that I have mentioned above. Give it a try on one of the grand test.In conclusion,Take advice from everyone, but do only what you find Useful/doableDon't go crazy due to FOMOAvailable knowledge in endless but you have a limit to your efforts so be selectiveAll the best.(EDIT!)So I decided to add a FAQ section based on comments I received here and in Facebook messages and to continue updating it frequently . Hope it solves any further doubts you have.FREQUENTLY ASKED QUESTIONSQUESTION : Is DAMS notes (or any other notes that you studied from) enough?ANSWER: I cross checked DAMS notes / DAMS books / review books/ notes from some subject faculties.I felt all these have almost the same content.So I decided to go ahead and read review books ( I am more comfortable reading from a book rather than reading hand written notes…probably because I have a very bad hand writing… so choose one of these sources (or whatever other notes you have) based on what you find most comfortable)I had used my foundation notes from DAMS a lot during my prefinal year when I was reading my final year textbooks for the first time . After that during my final year I felt a lot of topics were updated (like there was a new Parks PSM that year so foundation notes of PSM felt useless) so I read only my standard textbooks . During my internship I read from only the latest review books ( reading 2 year old notes at that time didn't make sense to me) and TND notes of the classes I liked of DAMS/DBMCI.Whatever you choose…just stick to one source…trust them with your heart and soul…don't waste time because of FOMO.QUESTION : How to manage time along with internship /whatever other work post you have.ANSWER :I was very irregular with my studies during my internship (it wasn't because I could not get sufficient time off from postings, it was because I wanted to take some time off from studies for a while)I studied regularly during January 2019 - April 2019 period.I was doing Non Academic Junior Residency in Department of Cardiac Radiology and Endo vascular Intervention at AIIMS NEW DELHI during that time.It helped a lot because :It was only few hours of work in the morning. I used to always get free before 1 pm and I could study in afternoon then.It provided me with a structured day…work every day in morning…study in afternoon… I needed that kind of structure for myself a lot at that time. For the first time during my MBBS I was sleeping on a fixed time and waking up on a fixed timeI have a tendency of binge watching TV series for days but going for work in the morning would break that cycle of endless binge and I would get to study after work so I wasn't binging anything for more than half day.I changed my perspective…I need 8 hours of sleep…at maximum on any day I can study only for 8 hours ( even 8 hours feel like torture to me…4-6 hours is my comfort level)…so even if I have to work for upto 8 hours my schedule should be OK. We worry so much about the time we are working that we ignore that during the time when we are not working we are actually wasting it away on youtube /facebook etc or wasting it on complaining about work. My focus was that non work time and how to utilize it most effectively.I feel I am addicted to my phone (aren't we all these days!)…so I used apps which would block me out of whatsapp/facebook/Instagram /youtube (there are literally endless number of such apps on play store) (also as we say poison kills poison…so using apps for my phone addiction! )…I would adjust block time in such a way to give me 1 hour slots of study and 10 min break after each slot.QUESTION : Which book you used for AIIMS previous year question papers and did you read the explanation?ANSWER : I had used Dr. Pritesh Singh AIIMS essence review and also Aim4AIIMS question papers (for the latest question papers which were not there in my AIIMS essence) … They both need corrections to be made to their answers…when in doubt search that topic (just type the key word in the search option ) in DAMS exclusive facebook page/any other subject faculty facebook page you follow…you will surely find that question already asked by someone and answered by faculty. Stick to that answer instead of what is given in the question paper.Use these books only for seeing the question…then go ahead and read the explanation from your notes /review book that you usually use.QUESTION : Is Harrison a must??!??!??ANSWER : It is not, but reading any good medicine book for building your concepts is.I didn't read Harrison.I gave it a try during my pre final year( read CNS, CVS, leukemia from it) . It was TOO much for me. I could not finish chapters. Those chapters which I could finish didn't make any sense in my head at the end.The best test for knowing whether you understand your topic well is by teaching it to others or trying to write it down for yourself in a single sheet of paper without referring to the book.You will be able to write a flow chart for it if you understand it…there will be deficits of factual values which you can always look up in books/latest guidelines …for example…symptoms /signs of stroke…do NCCT head…it's either hemorrhagic stroke…then do nothing just manage the blood pressure if it is more than *insert the latest BP cutoff for hemorrhagic stroke here*…or it could be ischemic stroke…then check for *latest* contraindications of thrombolysis…if it not contraindicated then check BP…too high BP becomes a contraindication *insert the latest BP cutoff for thrombolysis here*…then do thrombolysis…post thrombolysis management. Hope i made some sense here!I failed both those tests with Harrison. I was trying to read Harrison only because everyone around me was doing it and i had FOMO.I read CMDT + “choti harri” instead.CMDT (CURRENT MEDICAL DIAGNOSIS AND TREATMENT by McGraw-Hill publications) :It's a book which gets updated every year and a new edition is released every year. It has investigations and treatment explained very beautifully…it uses the words like “drug of choice is” (and all everyone cares about is what to answer…I don't want to read 2 huge pages in any book where I am left on my own to decide what should be the drug of choice!)…it doesn't have Pathology part in much detail (I was okay with that because Robbins is the best source to read Pathology from…not Harrison!)…. DR. THAMEEM TEACHES FROM IT DURING HIS LECTURE (I know i could have written just that last line and it would have been sufficient)“choti harri / baby harry (!)” (Harrison MANUAL of medicine):This book is the short version of Harrison PRINCIPLES of internal medicine (badi harri /papa harry) from the same authors. It has ALL the algorithms, flow charts, tables and a summary of everything from badi harri. So you don't have to carry around the burden of badi harri and still you get all the needed information. Highly recommend it.( on a side note, choti harri is usually released 1 year after that edition of badi harri…so 20th edition of choti harri is yet to be released as of June 2019).I didn't read any other textbook like Davidson /Matthew's. So I don't know how they are and i dont like to give a judgement about a book without actually reading it. So I will suggest you to ask someone who has read it themselves.OrJudge a book for yourself. Take an important topic…say asthma…read it from every source available…Harrison/CMDT/Davidson /whatever book you want to give a try…record how much time it took for you to complete each source, the amount of information given and how understandable it is/ease of reading. Then stick to what you like the most. All 3 factors are equally important.QUESTION :How to memorize so much content available?ANSWER: I feel if you can understand the logic behind something then you can avoid adding it to your things to remember list. And logic stays in your head for much longer. While what you try to memorize, you will eventually forget.I also analysed AIIMS previous year question papers well and felt that they very very rarely ask factual information so I was able to skip those.So I just used a small notebook in which I would write down all that i wanted to memorize for example all the formulas, cutoff for BP in strokes, and other such key information which is relevant clinically . I don't have a good memory for factual stuff so I didn't try to force myself in memorizing stuff which is not asked in AIIMS exam and is not relevant clinically like diameter of eye, length of some nerve etc. If you can look it up in your book then why should we memorize it and thus should not be asked in a good quality exam. The notebook which I mentioned here I used to carry with me all the time, I used to read it if i would get free time during postings and because it had clinically relevant stuff only so I used it few times to look up something for patient management too.QUESTION : I couldn't find the mock test on AIIMS website which you had mentioned in your previous post.ANSWER : It is available on your registration page from where you download your admit card. It will be available 1-2 week before your exam.(I wanted to add screenshots of that page here to give you idea about it in advance but it has already been removed from my page…may be one of you can send those to me when you get to access the mock test in November 2019 session)QUESTION : How much MARROW question bank you used and is it worth buying?ANSWER : I was a MARROW PRO plan B user from July 2018 - May 2019. Plan B contain test series and question bank, it doesn't include lecture videos. I didn't use MARROW much, I had solved only few modules in it. Also as I didn't have access to the videos i dont know how they are. I don't like giving judgement about a source without using it myself. MARROW test series had previous year question papers given in the form of tests which I thought was a great initiative from their side.My view point on the amount of question practice one needs is a little different.What is the logic behind question solving :To know how to apply your knowledge into the questions ( if you can't use your knowledge in getting marks by answering questions correctly then you need to do more practice…no excuses allowed!)Solve 3 hour grand tests /CBT /CLT/whatever your coaching calls it : start around mid year…don't leave it for the end…don't wait till you have “sufficient” knowledge to start solving it…YOU WILL NEVER FEEL YOU HAVE SUFFICIENT KNOWLEDGE…so start today…test takes around 3 hours or 3.5 hours based on the pattern…doing an analysis of the test takes another 5-6 hours (without the analysis part the 3.5 hours that you spent giving the test is almost useless). I used to watch discussion videos of the test at 1.5* times speed and add the new information to my notes…I used to try and see the entire explanation video because even when I knew a topic very well there was always something new that faculty could add and it makes a great revision source as the most important topics get repeated in every test and listening to it again and again just works as revision. ( you have no idea how many times till now I have heard Dr. Deepti Bahl explain the most common and 2nd most common uterine anomaly in a video discussion and I dont think I can ever forget it).Don't leave grand tests for the month just before your exam as I mentioned above each test takes around 9-10 hour (3 hour for the test and 5-6 hours for the explanation)…that's atleast one entire day worth of studying!!…you should be doing revision of your notes during the last month instead.Try to solve every question, especially those that you have no idea about. You learn how to apply logic in question solving by those questions. You will never know all the answers accurately. But you can learn how to rule out options, how to identify keywords, how to increase speed of question solving. Initially you will apply faulty logic, eventually you will learn and get better at it and finally you will have the confidence to take those risks in your main exam. (also if you can solve 150 questions when you have knowledge about just 100 questions sounds like a good deal to me)Make your own exam strategy. (I have mentioned my exam strategy in the post whose link i have mentioned above, feel free to take inspiration from it)Having said all this, don't use question banks as your source of learning a subject (you need notes or textbook for it) and don't do stuff because of FOMO. I feel DAMS /DBMI content in itself is sufficient but you should decide it for yourself.QUESTION : I just have * insert any time duration in months * before exam left, is it sufficient?ANSWER : I think 4-6 months of dedicated studying is sufficient if you already have good understanding of your subjects. If you are weak in any subject then you will need to give it extra timeOf these 4-6 months keep last 2 months for revision and 1 week before the exam for quick revision.QUESTION : How many revisions you did?ANSWER : I did 2 structured revisions before the exam as I mentioned above. Having said that everytime you hear or talk about a topic with your friend is a revision and everytime you solve a question in a grand test and listen to the discussion video is a revision.

1. The pilot who got stuck outside the aircraft at 17,000 ft​This is one of the most fascinating flying stories of all time. I am going to explain this incident by combining, editing and modifying the text from various online sources. I will also be using the screenshots from National Geographic's "Air Crash Investigation."British Airways Flight 5390 left Birmingham Airport at 7.20am on a fine morning in 1990, heading for Malaga in Spain. At the controls were Captain Tim Lancaster, 42, and his co-pilot, 39-year-old Alastair Atchison, both experienced flyers, and their take-off was routine.Co-pilot Atchison handled a routine take-off, and relinquished control to Lancaster as the plane established itself in its climb. Both pilots subsequently released their shoulder harnesses, while Lancaster loosened his lap belt as well.About 15 minutes into the flight, the cabin crew had begun to prepare for meal service. The plane had climbed to 17,300 feet (5,270 m) over Didcot, Oxfordshire. Suddenly, there was a loud bang, and the fuselage quickly filled with condensation. The left windscreen, on the captain's side of the cockpit, had separated from the forward fuselage. Lancaster was jerked out of his seat by the rushing air and forced head first out of the cockpit, his knees snagging onto the flight controls. This left him with his whole upper torso out of the aircraft, and only his legs inside. The door to the flight deck was blown out onto the radio and navigation console, blocking the throttle control which caused the plane to continue gaining speed as they descended, while papers and other debris in the passenger cabin began blowing towards the cockpit.On the flight deck at the time, flight attendant Nigel Ogden quickly latched his hands onto the captain's belt. Susan Price and another flight attendant began to reassure passengers, secure loose objects, and take up emergency positions. Meanwhile, Lancaster was being battered and frozen in the 550+ KMH wind, and was losing consciousness due to the thin air.​Atchison began an emergency descent, re-engaged the temporarily disabled autopilot, and broadcast a distress call. Due to rushing air on the flight deck, he was unable to hear the response from air traffic control. The difficulty in establishing two-way communication led to a delay in British Airways being informed of the emergency and consequently delayed the implementation of the British Airways Emergency Procedure Information Centre plan.Ogden, still latched onto Lancaster, had begun to suffer from frostbite, bruising and exhaustion. He was relieved by the remaining two flight attendants. By this time Lancaster had already shifted an additional six to eight inches out the window. From the flight deck, the flight and cabin crew were able to view his head and torso through the left direct vision window. Lancaster's face was continuously hitting the direct vision window; when cabin crew saw this and noticed that Lancaster's eyes were opened but not blinking despite the force against the window, they assumed that Lancaster was dead. Atchison ordered the cabin crew to not release Lancaster's body despite the assumption of his death because he knew that releasing the body might cause it to fly into the left engine and cause an engine fire or failure which would cause further problems for Atchison in an already highly stressful environment.​Atchison eventually received clearance from air traffic control to land at Southampton, while the flight attendants managed in extreme conditions to free Lancaster's ankles from the flight controls and hold on to him for the remainder of the flight. By 07:55 the aircraft had landed safely on Runway 02 at Southampton. Passengers immediately disembarked from the front and rear stairs, and emergency crews retrieved Lancaster.The captains body had suffered tremendous physical trauma, getting sucked out of the cockpit and getting pinned down by 600 kmph winds on the cockpit window at -17 degree Celsius. He would have also suffered oxygen deprevition for more than 22 minutes.Despite the trauma captain Lancaster suffered, there is a small twist to his story. He somehow survived this horrific ordeal with two bone fractures, bruising ,shock frostbite and a broken finger.There were no casualties on this flight.Less than five months after the accident Lancaster was working again. He later retired from British Airways when he reached the company's mandatory retirement age of 55 at the time. In 2005 Lancaster was reported flying for EasyJet.​Actual photo of the WindshieldBy flying alone, battling 600+KMPH of winds at -17 degree Celsius and oxygen deprivation, Co-Pilot Alastair Atchison's achievement in saving this plane is truly outstanding.First Officer Alastair Stuart Atchison and cabin crew member Susan Gibbins were awarded the Queen's Commendation for Valuable Service in the Air award in recognition of their extraordinary flying under extreme conditions.Accident investigators later discovered that when the windscreen had been refitted to the plane the night before, the wrong bolts had been used to secure it; they were little more than half a millimeter too small, and had failed under intense air pressure. Surprisingly the old bolts were also incorrect ones; the engineer, working under pressure and without reference to manuals, had simply replaced the old bolts with new ones on a like-for-like basis.As a result of the incident, windscreens on British Airways planes are now secured by bolts on the inside of the plane, rather than the outside, putting them under even less pressure.It is highly recommended that you watch the documentary "Aircrash Investigation : Ripped out of the cockpit"Sources:1. Wikipedia: British Airways Flight 53902. June 10, 1990: Miracle of BA Flight 5390 as captain is sucked out of the cockpit – and survives2. Ghost Plane!​SituationA Helios Airways Boeing 737 is circling the city of Athens for more than two hours in a holding pattern. There is no communications from the plane even after multiple attempts. The Greek air force sends two of its fighter jets to investigate the situation. One of them is in a shooting position behind the 737 while the other one is trying to visually access the situation. The fighter pilot can see passengers on their seats but none of them are moving or reacting to the presence of a fighter jet. There is one non responsive person on the pilots seats slumped over the controls.​Then the fighter pilot radios that there is one person moving in the cockpit! But this person is not communicating with the fighter pilot.​Sounds like a movie?This true story is as suspenseful as a good thriller movie. I strongly suggest that you watch this episode of Air Crash Investigation. It is highly dramatized and made nearly like a movie itself.Air Crash Investigation - Ghost Plane - Helios Flight 5223. AirCraft roof ripped off​\\​Aloha Airlines Flight 243 was a scheduled Aloha Airlines flight between Hilo and Honolulu in Hawaii. On April 28, 1988, a Boeing 737-297 serving the flight suffered extensive damage after an explosive decompression in flight. Earlier, in the first incident, we saw the captain enduring a huge physical stress, in this case, the passengers are sitting on an airplane seat with no roof.I suggest you to watch "Air Crash Investigation: Hanging by a thread":Per Page on youtube.com:The flight departed Hilo at 13:25 HST on 28 April 1988 with six crew members and 89 passengers, bound for Honolulu. No unusual occurrences were noticed during the pre-departure inspection of the aircraft. The aircraft had previously completed 3 round-trip flights from Honolulu to Hilo, Maui, and Kauai that day, all uneventful. Meteorological conditions were checked but no advisories for weather phenomenon occurred along the air route, per Airman’s meteorological information (AIRMET) or significant meteorological information (SIGMET). The captain was 44-year-old Robert Schornstheimer. He was an experienced pilot with 8,500 flight hours; 6,700 of those were in Boeing 737s. The first officer was 36-year-old Madeline "Mimi" Tompkins. She also had significant experience flying 737s, having logged 3,500 of her total 8,000 flight hours in them.No unusual occurrences were reported during the take-off and ascent. Around 13:48, as the aircraft reached its normal flight altitude of 24,000 feet (7,300 m) about 23 nautical miles (43 km) south-southeast of Kahului, Maui, a small section on the left side of the roof ruptured with a "whooshing" sound. The captain felt the aircraft roll left and right, and the controls went loose. The first officer noticed pieces of grey insulation floating over the cabin. The door to the cockpit was gone so the captain could look behind him and see blue sky. The resulting explosive decompression tore off a large section of the roof, consisting of the entire top half of the aircraft skin extending from just behind the cockpit to the fore-wing area.​First officer Madeline "Mimi" Tompkins was flying the plane at the time of the incident. After discovering the damage, the captain took over and steered the plane to the closest airport, on Maui island. Thirteen minutes later, the crew performed an emergency landing on Kahului Airport's Runway 2. Upon landing, the crew deployed the aircraft's emergency evacuation slides and evacuated passengers from the aircraft quickly. Tompkins assisted passengers down the evacuation all, 65 people were reported injured, eight seriously. At the time, Maui had no plan for a disaster of this type. The injured were taken to the hospital by the tour vans from Akamai Tours (now defunct) driven by office personnel and mechanics, since the island only had a couple of ambulances. Air traffic control radioed Akamai and requested as many of their 15-passenger vans as they could spare to go to the airport (three miles away) to transport the injured. Two of the Akamai drivers were former medics and established a triage on the runway. The aircraft was a write-off.58 year old Flight Attendant Clarabelle Lansing was the only fatality; she was swept overboard while standing near the fifth row seats. Despite an extensive search her body was never found. She was a veteran flight attendant of 37 years at the time of the accident.​Real photo of the planeSource: Wikipedia Aloha Airlines Flight 2434. Strange Lights around the plane + all four engines fail​British Airways Flight 9, was a scheduled flight from London Heathrow to Auckland, with stops in Bombay, Madras, Kuala Lumpur, Perth, and Melbourne. It is a Boeing 747 Jumbo Jet with 263 people on board.​The plane was flying above Indian ocean near Java at night. After few hours, strange bright lights started appearing all around the aircraft. Despite the weather radar showing clear skies, the crew switched on engine anti-ice and the passenger seat belt signs as a precaution.I strongly suggest to watch this dramatized documentary " Aircrash Investigation: Falling from the sky" here --> youtube.com.This incident is better watched than read. Even a book was written about this incident named All Four Engines Have Failed: The True and Triumphant Story of Flight BA 009 and the Jakarta Incident: Betty TootellBut if you choose to read then continue (otherwise skip to the next incident):As the flight progressed, smoke began to accumulate in the passenger cabin of the aircraft; it was first assumed to be cigarette smoke. However, it soon began to grow thicker and had an ominous odour of sulphur. Passengers who had a view out the aircraft windows noted that the engines were unusually bright, with light shining forward through the fan blades and producing a stroboscopic effect.At approximately 13:42 UTC (20:42 Jakarta time), the number four Rolls-Royce RB211 engine began surging and soon flamed out. The flight crew immediately performed the engine shutdown drill, quickly cutting off fuel supply and arming the fire extinguishers. Less than a minute later, at 13:43 UTC (20:43 Jakarta time), engine two surged and flamed out. Within seconds, and almost simultaneously, engines one and three flamed out, prompting the flight engineer to exclaim, "I don't believe it — all four engines have failed!"Without engine thrust, a 747-200 has a glide ratio of approximately 15:1, meaning it can glide forward 15 kilometres for every kilometre it drops. The flight crew quickly determined that the aircraft was capable of gliding for 23 minutes and covering 91 nautical miles (169 km) from its flight level of 37,000 feet (11,000 m). At 13:44 UTC (20:44 Jakarta time), Greaves declared an emergency to the local air traffic control authority, stating that all four engines had failed. However, Jakarta Area Control misunderstood the message, interpreting the call as meaning that only engine number four had shut down. It was only after a nearby Garuda Indonesia flight relayed the message to Air Traffic Control that it was correctly understood. Despite the crew "squawking" the emergency transponder setting of 7700, the 747 could not be located by Air Traffic Control on their radar screens.Many passengers, fearing for their lives, wrote notes to relatives. One such passenger was Charles Capewell, who scrawled "Ma. In trouble. Plane going down. Will do best for boys. We love you. Sorry. Pa XXX" on the cover of his ticket wallet.Owing to the high Indonesian mountains on the south coast of the island of Java, an altitude of at least 11,500 feet (3,500 m) was required to cross the coast safely. The crew decided that if the aircraft was unable to maintain altitude by the time they reached 12,000 feet (3,700 m) they would turn back out to sea and attempt to ditch into the Indian Ocean. The crew began engine restart drills, despite being well outside the recommended maximum engine in-flight start envelope altitude of 28,000 feet (8,500 m). The restart attempts failed.Despite the lack of time, Captain Moody made an announcement to the passengers that has been described as "a masterpiece of understatement":"Ladies and gentlemen, this is your captain speaking. We have a small problem. All four engines have stopped. We are doing our damnedest to get them going again. I trust you are not in too much distress."​Without the engines noise, the planes was totally silent and the lights in the cabin went out!As pressure within the cabin fell, oxygen masks dropped from the ceiling – an automatic emergency measure to make up for the lack of air.Without the engines, most of electronic things will stop working including the public addressing system.Lead Flight attendant came to the the cabin with a megaphone and announced:"Can you hear me. There is a small problem with our public addressing system. Place your mask over your mouth and nose and breath normally"​On the flight deck, however, Greaves's mask was broken; the delivery tube had detached from the rest of the mask. Moody swiftly decided to descend at 1,800 m per minute to an altitude where there was enough pressure in the outside atmosphere to breathe almost normally.​At 13,500 feet (4,100 m), the crew was approaching the altitude at which they would have to turn over the ocean and attempt a risky ditching. Although there were guidelines for the water landing procedure, no one had ever tried it in a Boeing 747, nor has anyone since. As they performed the engine restart procedure, engine number four finally started, and at 13:56 UTC (20:56 Jakarta time), Moody used its power to reduce the rate of descent. Shortly thereafter, engine three restarted, allowing him to climb slowly. Shortly after that, engines one and two successfully restarted as well. The crew subsequently requested and expedited an increase in altitude to clear the high mountains of Indonesia.As the aircraft approached its target altitude, the strange lights on the windscreen returned. Moody throttled back; however, engine number two surged again and was shut down. The crew immediately descended and held 12,000 feet (3,700 m).As Flight 9 approached Jakarta, the crew found it difficult to see anything through the windscreen, and made the approach almost entirely on instruments, despite reports of good visibility. The crew decided to fly the Instrument Landing System (ILS); however, the vertical guidance system was inoperative, so they were forced to fly with only the lateral guidance as the first officer monitored the airport's Distance Measuring Equipment (DME). He then called out how high they should be at each DME step along the final approach to the runway, creating a virtual glide slope for them to follow. It was, in Moody's words, "a bit like negotiating one's way up a badger's arse." Although the runway lights could be made out through a small strip of the windscreen, the landing lights on the aircraft seemed to be inoperable. After landing, the flight crew found it impossible to taxi, due to glare from apron floodlights which made the already sandblasted windscreen opaque.They had landed the jumbo jet blind as their windscreen had nearly became opaque due to scratches caused by the strange lights!The crew received various awards, including the Queen's Commendation for Valuable Service in the Air and medals from the British Air Line Pilots Association. Following the accident, the crew and passengers formed the Galunggung Gliding Club as a means to keep in contact. G-BDXH's engineless flight entered the Guinness Book of Records as the longest glide in a non-purpose-built aircraft (this record was later broken by Air Canada Flight 143 and Air Transat Flight 236).One of the passengers, Betty Tootell, wrote a book about the accident, All Four Engines Have Failed. She managed to trace some 200 of the 247 passengers on the flight, and went on to marry a fellow passenger, James Ferguson, who had been seated in the row in front of her. She notes: "The 28th December 2006 marks the start of our 14th year of honeymoon, and on the 24th June 2007 many passengers and crew will no doubt gather to celebrate the 25th anniversary of our mid-air adventure."​Post-flight investigation revealed that this flights problems had been caused by flying through a cloud of volcanic ash from the eruption of Mount Galunggung. Because the ash cloud was dry, it did not appear on the weather radar, which was designed to detect the moisture in clouds. The cloud sandblasted the windscreen and landing light covers and clogged the engines. As the ash entered the engines, it melted in the combustion chambers and adhered to the inside of the power-plant. As the engine cooled from inactivity, and as the aircraft descended out of the ash cloud, the molten ash solidified and enough of it broke off for air to again flow smoothly through the engine, allowing a successful restart. The engines had enough electrical power to restart because one generator and the on-board batteries were still operating; electrical power was required for ignition of the engines.The strange lights were initially called St Elmo's fire, but later it was found that the glow experienced was from the impact of ash particles on the leading edges of the aircraft, similar to that seen by operators of sandblasting equipment.5. Gimli Glider - Ran Out of FuelOn July 23, 1983, Captain Robert Pearson, 48, and First Officer Maurice Quintal are at the controls of a brand new Air Canada's Boeing 767.At 41,000 feet (12 497 m) over Red Lake, Ontario, the cockpit warning system chimed four times and indicated a fuel pressure problem on the left side. Thinking the fuel pump had failed the pilots turned it off; the tanks are above the engines so gravity will take over and feed the engines. The computer said that there was still plenty of fuel, but this was based on the wrong calculations. A few moments later a second fuel pressure alarm sounded, and the pilots decided to divert to Winnipeg. Within seconds the left engine failed and preparations were made for a one-engine landing.While they attempted to restart the engine and communicate with controllers in Winnipeg for an emergency landing, the warning system sounded again, this time with a long "bong". The sound was the "all engines out" sound, an event that was never simulated during training. Seconds later the right side engine stopped and the 767 lost all power leaving the cockpit suddenly silent and allowing the cockpit voice recorder to easily pick out the words "Oh, f%$#!".The 767 is based on a "glass cockpit" concept in which mechanical instruments are replaced with display screen monitors. The jet engines also delivered electrical power to the aircraft, so most of the instrumentation suddenly went dead. One of the lost instruments was the vertical-rate indicator, which would let the pilots know how fast they were sinking and therefore how far they could glide.The engines also supplied power to the hydraulic systems, without which a plane the size of the 767 could not be controlled.However, Boeing actually planned for this possible failure and included a device known as a ram air turbine that automatically popped open on the side of the plane, using some of the plane's residual velocity to spin a propeller-driven generator and provide enough power to the hydraulics to make it controllable.​RAM Air TurbineWith nothing in the emergency guide on flying the aircraft with both engines out, Pearson glided the plane at 220 knots (407 km/h), his best guess as to the optimum airspeed. Copilot Maurice Quintal began making calculations to see if they would reach Winnipeg. He used the altitude from one of the mechanical backup instruments, while the distance travelled was supplied by the air traffic controllers in Winnipeg, who measured the distance the plane's echo moved on their radar screens. The controllers and Quintal both calculated that Flight 143 would not make Winnipeg, as the plane had lost 5,000 ft in 10 nautical miles (1.5 km in 19 km) giving a glide ratio of approximately 12:1.Stationed at the former Royal Canadian Air Force Base, Quintal selected Gimli to be the attempted place of landing. Since his time in the service, Quintal did not know the Gimli airport had become a drag racing ground. Also not knowing one of its parallel runways was now being used for auto racing. To further complicate the situation, there were many cars, campers and families close to the former runway as it was "Family Day" for the Winnipeg Sports Car Club.As they approached Quintal did a power-off "gravity drop" of the main landing gear, but the nose wheel, despite being built to open by swinging backwards with the force of the wind, would not lock. The ever-reducing speed of the plane also reduced the effectiveness of The "RAT" (Ram Air Turbine, a propeller driven hydraulic pump tucked under the belly of the 767. The RAT can supply just enough hydraulic pressure to move the control surfaces and enable a dead-stick landing) and the plane became increasingly difficult to control. As they grew nearer it became apparent that they were too high, and Pearson executed a manoeuvre known as a "forward slip" to increase their drag and reduce their altitude. This gave passengers on one side of the aircraft a view of the ground while passengers on the other side of the plane seen blue skies. With the reduction of speed and altitude the 767 silently leveled off and the main gear touched down. Pearson "stood on the brakes" the instant the plane touched the runway, blowing out several of the plane's tires.Two kids were cycling at the end of the runway. They looked back and saw a big jet approaching them. The terrified kids tried to outrun the plane.​The plane came to a stop at the end of the runway in a nose-down position due to the unlocked nose gear, only a few hundred feet from spectators of Family Day and the kids at the end of the runway.None of the 61 passengers were hurt during the landing, the only injuries that resulted from the landing of Flight 143 came from passengers exiting the rear emergency slide, a near vertical angle because of the nose down position of the plane. A minor fire in the nose area was quickly put out by course workers, who rushed over with fire extinguishers.​Real photoWithin two days the aircraft was repaired and flown out of Gimli, after approximately one million dollars worth of repairs, Aircraft #604 the Boeing 767 known as "The Gimli Glider", is to this day still in the Air Canada fleet.Note: The mechanics sent from Winnipeg Airport to repair the aircraft, also ran out of fuel in their van on their way to Gimli.​Why this plane crashed?At the time of the incident, Canada was converting to the metric system. As part of this process, the new 767s being acquired by Air Canada were the first to be calibrated for metric units (litres and kilograms) instead of customary units (gallons and pounds). All other aircraft were still operating with Imperial units (gallons and pounds). The pilots miscalculated the fuel required for the trip in pounds instead of kilograms.Instead of 22,300 kg of fuel, they had 22,300 pounds on board — 10,100 kg, about half the amount required to reach their destination. This simple problem with the units had caused this crash.Sources:- Gimli Community Web, Gimli GliderIf you would like to watch it, then search for "Air Crash Investigation: Gimli Glider"6) Kids fly a commercial jet​Aeroflot Flight 593, an A310 was en route from Sheremetyevo International Airport to Hong Kong Kai Tak International Airport with 75 occupants aboard, of whom 63 were passengers. Most of the passengers were businessmen from Hong Kong and Taiwan who were looking for economic opportunities in Russia.The relief pilot, Yaroslav Kudrinsky, was taking his two children on their first international flight, and they were brought to the cockpit while he was on duty. Aeroflot allowed families of pilots to travel at a discounted rate once per year. Five people were in the cockpit: Kudrinsky, copilot Igor Piskaryov, Kudrinsky's son Eldar , his daughter Yana, and another pilot, V. Makarov, who was flying as a passenger.With the autopilot active, Kudrinsky, against regulations, let the children sit at the controls. First his daughter Yana took the pilot's left front seat. Kudrinsky adjusted the autopilot's heading to give her the impression that she was turning the plane, though she actually had no control of the aircraft. Shortly thereafter Eldar occupied the pilot's seat. Unlike his sister, Eldar applied enough force to the control column to contradict the autopilot for 30 seconds. This caused the flight computer to switch the plane's ailerons to manual control while maintaining control over the other flight systems. A silent indicator light came on to alert the pilots to this partial disengagement. The pilots, who had previously flown Russian-designed planes which had audible warning signals, apparently failed to notice it.The first to notice a problem was Eldar, who observed that the plane was banking right. Shortly after, the flight path indicator changed to show the new flight path of the aircraft as it turned. Since the turn was continuous, the resulting predicted flight path drawn on screen was a 180-degree turn. This indication is similar to the indications shown when in a holding pattern, where a 180-degree turn is intentional to remain in one place. This confused the pilots for nine seconds. During this confusion, the plane banked past a 45-degree angle (steeper than it was designed for). This increased the g-force on the pilots and crew, making it impossible for them to regain control. After the plane banked to 90 degrees, the remaining functions of the autopilot tried to correct its plummeting altitude by putting the plane in an almost vertical ascent, nearly stalling the plane. The co-pilot and Eldar managed to get the plane into a nosedive, which reduced the g-forces and enabled the captain to take the controls. Though he and his co-pilot did regain control and level out the wings, their altitude by then was too low to recover, and the plane crashed at high vertical speed, estimated at 70 m/s (14,000 ft/min). All 75 aboard were killed.The aircraft crashed with its landing gear up, and all passengers had been prepared for an emergency, as they were strapped into their seats. No distress calls were made prior to the crash. Despite the struggles of both pilots to save the aircraft, it was later concluded that if they had just let go of the control column, the autopilot would have automatically taken action to prevent stalling, thus avoiding the accident.The wreckage was located on a remote hillside approximately 20 kilometres (12 mi) east of Mezhdurechensk, Kemerovo Oblast, Russia; the flight data recorders were found on the second day of searching.If you would like to watch it, then search for "Air Crash Investigation: Kids in the cockpit"Source: Aeroflot Flight 593I will add more details and more incidents soon.7. TACA Flight 110 [Remarkable landing]8. Hudson River Ditching9. Air Transat flight 236 [Flying with empty fuel tank]10. Malaysian Airlines MH370 (But I have only theories and assumptions, so I am going to leave it.)by - Kshitij SalgunanPS:- Due to readers demand for explanation of the Ghost plane story, I have written a fully fledged answer here : What happened to Helios flight 522-the ghost plane?

AFCIsAFCIs (arc fault circuit interrupters) were included in much earlier editions of the NEC - it’s just that the 2017 Edition expanded on where they are required.So it would be incorrect to say that the 2017 NEC corrected a substantial problem by the inclusion of AFCIs in the 2017 Edition of the NEC.AFCIs and Their DesignThe NEC is not responsible for the design of electrical equipment, it deals with the installation of that equipment - more specifically to safety related to the installation.Organizations such as Underwriters Laboratories (UL), along with the manufacturers and other interested industry organizations, write safety standards for electrical equipment, including AFCIs. The manufacturers ultimately are responsible for the design, manufacturer and safety of electrical devices such as AFCIs. Part of the way that the manufacturers work meet that responsibility is to design, manufacturer and test their devices to recognized safety standards such as UL Standards. The manufacturers also enlist independent testing labs such as UL and others to test their devices to these recognized safety standards. (That is why you see the UL mark and other such marks on many electrical devices.) Beyond that many electrical equipment manufacturers have their own internal safety standards that exceed those required by safety standards.NECThe NEC (National Electrical Code) is the electrical installation code for all of the 50 states and all US territories. It is revised every three years.Before too long the 2020 edition will be available.Access to the NECAccess to the 2017 NEC is available by registering for the free access to the NFPA (National Fire Protection Association) web site. Many larger local libraries have a copy, or are able to order one through the interlibrary loan program.The NEC clearly identifies additions and changes by highlighting the text associated with it.NEC As LawThe NEC by itself is not a law in the US - it must be enacted (promulgated) into law by a governing body. For places covered by the Occupational Safety and Health Act - OSHA (most businesses) the NEC is a Federal law.For residences the NEC is promulgated into law by states laws or local ordinances. Below is a map of which states are currently following which version of the NEC: NEC® adoption maps - NFPALocal jurisdictions within a state may follow a more recent edition of the NEC, but not an earlier one. If you are in a state that follows an edition of the NEC earlier than the 2017 Edition contact the local organization responsible for enforcement of electrical codes in your area to find out what version of the NEC they are currently following.Background on the 2017 NEC RevisionsThere were 4,012 public inputs submitted to NFPA recommending changes for the 2017 NEC and 1,235 First Revisions resulted. Then 1513 Public Comments were submitted and 559 Second Revisions were produced. There were 9 articles proposed and 5 new articles that appear in the 2017 NEC.The list of major (technical) code changes (not including purely editorial and formatting changes) from the 2014 to the 2017 edition is 45 pages long.New Articles in the 2017 NEC• Article 425 - Fixed Resistance and Electrode Industrial Process Heating Equipment• Article 691 - Large-Scale Photovoltaic (PV) Electric Supply Stations• Article 706 - Energy Storage Systems (ESS)• Article 710 - Stand Alone Systems• Article 712 - Direct Current MicrogridsSummary of Significant Changes to the 2017 NECIt should be obvious by now to the reader that there are way too many changes that have been made to the 2017 NEC to possibly be listed here. In addition to that, what might be “substantial” to one person might be of no interest to another.However several organizations have done an excellent job of summarizing the changes. I will leave it up to you to decide which ones are significant to you. The summary below is a 42 page long Power Point presentation.https://www.necanet.org/docs/default-source/17presentations/e-29_a-look-at-the-2017-nec-significant-changes_johnston_dollard_0800-0850_101017.pdf?sfvrsn=2There is a danger in solely counting on the words contained in any summaries like this. Because of limited space these summaries may leave out wording that appears in the NEC that is important to the issue at hand. The reader is therefore cautioned to always refer to the NEC itself to obtain the complete wording.A More Complete List of Significant Changes to the 2017 NECArticle 90—IntroductionSection 90.2(A) CoveredThe words “and removal” have been added in the first sentence of 90.2(A). This addition expands the NEC’s scope beyond installation requirements to include requirements addressing equipment removal. Current NEC rules require removal of equipment such as those for temporary power wiring removal and those for abandoned communications cables removal.Section 90.3 Arrangement 
and Figure 90.3Section 90.3 and associated Figure 90.3 have been revised. The revision clarifies that chapters 5–7 may modify or supplement requirements in chapters 1 through 7. The rules in chapters 5–7 can supplement or modify each other in addition to the provisions in chapters 1–4.For example, Article 770 contains requirements for optical fiber cables, and Section 770.3(A) indicates listed optical fiber cables shall be permitted in hazardous (classified) locations, and the cables shall be sealed in accordance with the requirements of 501.15, 502.15, 505.16 or 506.16, as applicable.Article 100­—DefinitionsMultiple definitions of words and terms pertaining to hazardous (classified) locations previously located in 500.2 have been relocated to Article 100. The words “as applied to Hazardous (Classified) Locations” have been added in brackets following each relocated term.Article 100—Readily AccessibleThe definition of “readily accessible” has been revised. The definition maintains most of its existing text and now includes “other than keys.” A new informational note addresses the common practice and use of keys in gaining accessibility under controlled conditions.Article 100—Field Evaluation Body and Field LabeledNew definitions of “field evaluation body” and “field labeled” have been incorporated into Article 100. These definitions have been developed from concepts derived from terms in NFPA 790, Standard for Competency of Third-Party Field Evaluation Bodies.Article 100—StructureThe definition of “structure” has been revised by adding “other than equipment.” The revision provides a clear differentiation between what constitutes electrical equipment as compared to structures.Article 110—Requirements for Electrical Installations110.3(A) ExaminationA new informational note No. 1 has been added to 110.3(A)(1). Previous Informational Note No. 1 has been renumbered as Informational Note No. 2. The new note clarifies that the term “equipment” used in this section can apply to new, reconditioned, refurbished or remanufactured equipment.110.3(C) ListingThe title of 110.3 has been revised to include the words “(product certification).” A new Subdivision (C) and associated informational note have been added to Section 110.3.The revision clarifies that listing (product certification) must be performed by recognized, qualified electrical testing laboratories, and the new informational note indicates that the Occupational Safety and Health Administration (OSHA) provides a list of such qualified laboratories.110.14(D) InstallationA new subdivision (D), “Installation,” has been added following 110.14(C). This subdivision incorporates mandatory torque tightening requirements for electrical terminations in accordance with the manufacturer’s instructions. It also allows for alternative methods as provided in the instructions. The informational note to 110.14 has been deleted because it is no longer necessary.110.21(A) Equipment MarkingsThe title of subdivision (A) has been changed to “Equipment Markings” from “Manufacturer’s Markings.” Section 110.21(A) has been renumbered as list items (1) and a new list item (2) with a new exception and informational note. New list item (2) provides marking requirements for reconditioned equipment including the responsible organization and date of reconditioning.110.24(A) Field MarkingA new last sentence has been added to 110.24(A) addressing calculations. The additional requirements are intended to document the calculation and make it available to those authorized to design, install, inspect, maintain or operate the system. The maximum level of available fault current can be obtained from published utility data or by use of calculation methods.Article 210­—Branch Circuits210.8(B) GFCI Protection in Other than Dwelling UnitsSection 210.8(B) now applies to all ­single-phase receptacles rated 150 volts (V) to ground or less and 50 amperes (A) or less as well as three-phase receptacles rated 150V to ground or less and 100A or less. The list of locations is expanded to include receptacle outlets in crawl spaces and receptacles in unfinished basements in 210.8(B)(10).210.12(B) Branch Circuit Extensions or Modifications—Dwelling Units and Dormitory UnitsThe existing requirements for arc-fault circuit-interrupter (AFCI) protection of branch-circuit extensions or modifications in dwelling units have been expanded to include dormitories. The same hazards exist in dormitories. AFCI protection in dormitories is expanded to include all outlets and devices in dormitory bathrooms.210.12(C) Guest Rooms and 
Guest SuitesNew subdivision (C), Guest Rooms and Guest Suites, has been added to Section 210.12. All 120V, single-phase, 15A and 20A branch circuits supplying outlets and devices installed in guest rooms and suites of hotels and motels must be protected by any of the AFCI methods listed in 210.12(A)(1) through (6). This new AFCI requirement applies to all guest rooms and suites without regard to cooking provisions.210.52(B)(1) Receptacle 
Outlets ServedException No. 2 to 210.52(B)(1) previously permitted only refrigeration equipment to be supplied by an individual branch circuit 15A or greater. This revision eliminates the potential conflict with 210.22, which provides general permission for individual branch circuits. This expands this permissive exception to other appliances, such as dishwashers, garbage disposals and microwaves, that may be supplied from a receptacle outlet.210.71 Meeting RoomsA new Section 210.71, Meeting Rooms, has been added to Article 210. This rule provides minimum requirements for installing receptacles in meeting rooms. All meeting rooms of not more than 1,000 square feet in other than dwelling units are now required to have receptacle outlets installed. Where movable partitions exist, room size is determined with partitions resulting in the smallest size meeting room(s). A minimum number of receptacle outlets is required and location are permitted to be determined by the owner or designer.Article 240—
Overcurrent ProtectionArticle 250—Grounding 
and Bonding
250.30(A)(4) ElectrodeSection 250.30(A)(4) has been revised and simplified, and Exception No. 1 was deleted. There is no longer a hierarchy of electrodes that must be used for grounding separately derived systems. The revision clarifies that the building grounding electrode system must be used when establishing a grounding electrode for a separately derived system. If installed outdoors, the grounding electrode for the separately derived system must comply with 250.30(C).250.104(A) Metal Water PipingSection 250.104(A) has been revised by adding “if or sufficient size” to (A)(3) and (A)(4). The wording “that is interconnected to form a building frame” has been added to subdivisions (C) and (D). The minimum bonding conductor or jumper sizes must be in accordance with Table 250.102(C)(1) rather than 250.66.250.122(F)(2) Multi-conductor CablesSection 250.122(F)(2) has been revised and arranged in a list format. The revisions address minimum sizes for equipment grounding conductors (EGCs) in multiconductor cables in 
parallel arrangements. A single EGC in each cable can be connected in parallel at each end and connected to a full-size EGC sized based on the overcurrent protection device for the entire circuit.Article 300—General Requirements for Wiring 
Methods and Materials
300.5(D) Protection From DamageElectrical metallic tubing (EMT) has been added to the list of raceways permitted to provide physical protection for direct-buried conductors and cables emerging from grade EMT, and associated elbows, couplings and fittings are permitted to be installed in concrete, in direct contact with the earth, approved as suitable for the condition. Section 358.10(B) requires that, where EMT is used in this manner, it must be where protected by corrosion protection and approved as suitable for the condition.300.5(G) Raceway SealsThe general requirements of first-level subdivision 300.5(G) are now correlated with sections 225.27 and 230.8. Where necessary, spare or unused raceways shall also be sealed. The type of sealants applied must be identified for use with the cable insulation, conductor insulation, bare conductor, shield or other components.300.22(B) Ducts Specifically Fabricated for Environmental Air[SB]A new exception in 300.22(B) correlates requirements for wiring in ducts specifically fabricated for environmental air between the NEC and NFPA 90A. NFPA 90A permits cables that are “directly associated with the air distribution system” and not to “exceed four feet.” This revision correlates existing requirements within the NEC. For example, in Chapter 8, first-level subdivision 800.113(B) contains the same permission.Table 310.15(B)(3)(c)Table 310.15(B)(3)(c), containing rooftop temperature correction factors, has been deleted. Raceways or cables must be installed a minimum distance of ⅞-inch above the roof. Where installed less than ⅞-inch above the roof to the bottom of the raceway or cable, use a temperature adder of 60°F.314.27(E) Separable Attachment FittingsNew subdivision (E) permits a new product referred to as a “separable attachment fitting.” This product is a listed locking support and mounting receptacle used in combination with compatible attachment fittings designed for the support of luminaires, paddle fans and so forth. These devices are designed to facilitate quick and easy interchange of luminaires or other equipment.328.14 InstallationSection 328.14 requires type MV cable to be installed, terminated and tested by qualified people. NECA 600 2014, Standard for Installing and Maintaining Medium-Voltage Cable, has been added to the Informational Note. It provides valuable information on installation requirements, guidelines for qualified installers, cable splicing and more.336.10 Uses PermittedNew list item (9) in 336.10 permits type TC-ER cable containing both power and control conductors to be used in one- and two-family dwelling units. In these installations, type TC-ER cable must be additionally marked “JP” to identify it as suitable for pulling through structural members. An exception permits the use of TC-ER cable for generators and associated equipment without the need to apply ampacity correction factors in accordance with 334.80 or 340.80.338.10(B) Branch Circuits 
and FeedersType SE cable with ungrounded conductor sizes 10 AWG and smaller, installed in thermal insulation, is limited to ampacity rating at 60°C. Larger SE cable installed in thermal insulation is no longer limited to an ampacity in the 60°C and can be applied at 75°C rating.358.10 Uses PermittedSection 358.10 has been revised for clarity and consistency with other .10 sections covering uses permitted for raceways. Permissive applications for EMT in 358.12 are relocated in 358.10 for clarity. Section 358.10(B) now addresses stainless steel EMT for corrosive environments.366.20, 368.20, 376.20 and 378.20 Conductors Connected in ParallelNew requirements for conductors connected in parallel are added in the .20 section of articles 366, 368, 376 and 378. Alternating current (AC) circuits connected in parallel must have conductors installed in groups consisting of not more than one conductor per phase, neutral or grounded conductor. The intention is to prevent current imbalance that can create heat and subsequent failure in the paralleled conductors due to inductive reactance.392.22(A) Number of Multiconductor Cables, Rated 2000 Volts or Less, in Cable TraysEach section of cable tray containing dividers must be treated individually with respect to fill calculations. A ladder-type tray that is divided with power on one side and control on the other side may now have the fill calculated by both 392.22(A)(1) and (A)(2) permitting a 50 percent fill calculation on the signal side of the tray.Article 400—Flexible Cords 
and Cables404.2(C) Switches Controlling Lighting LoadsThe reference to “habitable room” has been deleted. Bathrooms, hallways, stairways and rooms suitable for human habitation require the grounded conductor to be installed. A reference to the applicable building code has been included. The section parent text has been modified for clarity, for multiple switch locations. New text requires connection to switch devices (where required) beginning Jan. 1, 2020. New Section 404.22 has been added and correlates with this section.404.22 Electronic Lighting 
Control SwitchesAll electronic lighting control switches are required to be listed. As of Jan. 1, 2020, electronic lighting control switches (with exceptions) will not be permitted to introduce current on the equipment-grounding conductor during normal operation. Manufacturers will only make devices that place current on the equipment-grounding conductor during normal operation for replacement/retrofit.406.2 Outlet Box HoodSection 406.2 now contains a definition for “Outlet Box Hood” that applies where the term is used within Article 406. The hood does not serve to complete the electrical enclosure; it reduces the risk of water coming in contact with electrical components. Outlet box hoods are commonly known as a “bubble cover” or “in-use cover.”406.3(F) Receptacles with 
USB ChargerNew 406.3(F), Receptacles with USB Charger, permits these devices to be installed if they are listed and constructed so the Class 2 circuitry is integral with the receptacle. These devices are listed to ANSI/UL 498.406.12 Tamper-Resistant ReceptaclesSection 406.12 now addresses all 125- and 250V, nonlocking-type, 15- and 20-ampere receptacles. New occupancies have been added to the receptacle tamper-resistant requirements: Preschools and elementary education; business offices; corridors; waiting rooms and the like in clinics, medical and dental offices and outpatient facilities; assembly occupancies described in Section 518.2; and dormitories.422.16(B)(2) Built-in Dishwashers and Trash CompactorsFlexible cords supplying trash compactors are permitted to be between 3–4 feet long. A longer, flexible cord to facilitate connection for dishwashers in an adjacent space is permitted to be between 3–6½ feet long. The receptacle for a trash compactor must be located in the space occupied by the appliance or adjacent, and the receptacle for a built-in dishwasher must be located in the space adjacent to the space occupied by the dishwasher.422.31(A) and (B) Appliance DisconnectsPermanently connected appliances rated at not over 300 volt-amperes or 1/8 horsepower (hp) and motor operated appliances over 1/8 hp now require disconnects within sight or lockable in accordance with 110.25. The provisions for locking shall remain in place with or without the lock installed. This will require an identified accessory for circuit breakers.424.99(C) Installation Under 
Floor CoveringA grounding braid or sheath is required for all heating panels and heating panel sets installed under floor covering. Ground-fault circuit interrupter (GFCI)protection is required for all heating panels and heating panel sets installed under floor covering. The combination of a grounding braid or sheath and GFCI increases protection from shock.Article 425—Industrial Process Heating EquipmentArticle 425 is added to cover fixed industrial process heating employing electric resistance or electrode heating technology. Article 425’s requirements are similar to those in existing Article 424. It does not apply to heating and room air conditioning for personnel spaces, fixed heating equipment for pipelines/vessels, 
and induction and dielectric heating equipment and other special applications.430.99 CC Available Fault Current DocumentationSection 430.99 is new and requires documentation of the amount of available short-circuit current at a motor control center and the date the calculation was made. This information must be documented and available for the authority having jurisdiction to ensure compliance with 430.98(A). While a label or marking of available short-circuit current is not required on the motor control center, it may be the most feasible method of complying with this new requirement.430.130(A)(4) Circuits Containing Power Conversion EquipmentNew Section 430.130(A)(4) replaces the previous informational note to address the type of protective device for circuits containing power conversion equipment.Where an instantaneous trip circuit breaker or semiconductor fuses are used, they must be an integral part of a single listed assembly. This revision aligns the NEC with the applicable product standard, UL 508C.440.9 Grounding and BondingSection 440.9 now requires a “wire-type” equipment grounding conductor (EGC) for outdoor portions of metallic raceway systems that use nonthreaded fittings installed on a roof. Physical damage caused by activities on a roof combined with the weather can cause nonthreaded connectors and couplings to open, eliminating the fault return path on the metal raceway.440.65 Protection Devices for Room Air ConditionersSection 440.65 was retitled “Protection Devices.” The permitted protective devices are a leakage-current detection interrupter (LCDI), an arc-fault circuit interrupter (AFCI) or a heat-detecting circuit interrupter (HDCI). An HDCI incorporates all of the protection functions of an LCDI and includes a thermal detecting function to the air conditioner’s compressor against overheating.445.13(B) Ampacity of ConductorsNew Section 445.13(B) clarifies that generator-supplied conductors on the load side of an overcurrent protective device are not required to be sized at 115 percent of the generator nameplate current. Generator-supplied conductors on the load side of an overcurrent protective device (OCPD) may be applied in accordance with 240.21(B). The 115 percent rule applies only to conductors from the generator output terminals to an OCPD.445.18 Disconnecting Means and Shutdown or Prime MoverSection 445.18 has been separated into three first-level subdivisions to provide a more logical layout. Section 445.18(A) requires one or more disconnecting means (110.25) that simultaneously open all ungrounded conductors for all generators other than cord- and plug-connected portable generators. Section 445.18(B) requires a means to shut down the prime mover, disabling all prime mover start control circuits, rendering the prime mover incapable of starting. Section 445.18(C) provides clarity for required disconnects where generators are installed in parallel.480.3 Listing of Batteries and Management EquipmentSection 480.3 is new and requires all batteries and their associated battery management equipment to be listed. The listing requirement excludes lead-acid-type batteries. Catastrophic failures in new battery technology systems mandate rigorous testing for safety.500.2 DefinitionsMultiple definitions previously located in 500.2 have been relocated to Art-
icle 100.Section 2.2.2.1 of the NEC Style Manual requires that, if a term appears in more than two articles, it shall be included in Article 100. The words “as applied to Hazardous (Classified) Locations” have been added in brackets following each relocated defined term.500.5(A) Ammonia Areas are permitted to be UnclassifiedThe title of Subdivision (A) has been changed from “Classifications of Locations” to “General.” Classification of ammonia system refrigerant machinery rooms has been revised and clarified based on provided ventilation. Ammonia areas provided with adequate, continuous mechanical ventilation or initiation by a detection system at concentrations not exceeding 150 parts per million shall be permitted to be as unclassified locations. Section 505.5(A), covering the hazardous location classification zone system, includes a similar revision.505.15(A) New Limits for Protection Techniques in Zone 0 LocationsSection 505.15(A) provides requirements for allowable wiring methods in Class I, Zone 0 locations. The previous allowance for all intrinsically safe wiring methods in accordance with Article 504 has been reduced. Type “ia” intrinsically safe circuits and type “ma” encapsulation are suitable protection techniques for installations in Zone 0 hazardous locations.511.3(D) Classification of Locations in Commercial Repair GaragesSection 511.3(D) has been revised and titled “Repair Garages, Major.” This subdivision and new associated Table 511.3(D) provide area classification for major repair garages that use lighter-than-air gaseous fuels. The new informational note provides a reference to NFPA 30A and Table 8.3.2, the origin of these area classification requirements.511.8 Underground WiringA new Section 511.8, Underground Wiring, and an exception have been added. The driving text requires either threaded rigid metal conduit or intermediate metal conduit. The exception permits nonmetallic wiring methods under restrictive conditions dealing with depth, transitions to metallic conduit methods and installing an equipment grounding conductor.514.3(B)(3) Storage Tank 
Area ClassificationsA list item (3) in Section 514.3(B) is new and addresses liquefied natural gas (LNG), compressed natural gas (CNG), and liquefied petroleum gas (LPG) storage tank areas and locations. The new requirements provide separation distances from property lines and from other gas storage tanks. Table 514.3(B)(2) is referenced from this new list item for establishing classification of areas containing CNG, LNG or LPG storage or dispensing operations.514.11 Emergency Disconnects for Motor Fuel Dispensing EquipmentSection 514.11 has been revised to align with the requirements in NFPA 30A 2015. Subdivision (A) now addresses only emergency disconnects for dispensing equipment and no longer addresses circuit maintenance disconnects and breaking all conductors of the circuit(s). Section 514.13 still provides these requirements. Subdivisions (B) and (C) address locations of disconnects for attended and unattended dispensing facilities, respectively.Article 516 RewrittenArticle 516, Spray Application, Dipping, Coating, and Printing Processes Using Flammable or Combustible Materials, has been rewritten to align more closely with NFPA 33 and 34 including extracted material. The rewrite includes organizing the previous requirements into separately titled parts of Article 516. The revisions provide a more logical layout, which enhances usability, and more consistency with NEC Style Manual requirements.517.2 Governing Body of Health Care FacilitiesThe term “governing body” appears in multiple sections in NEC Article 517. A new definition of the term has been added to Section 517.2 to meet NEC Style Manual requirements. The new definition correlates between NFPA 99, Health Care Code, and NFPA 70, National Electrical Code, as it is an extracted definition. This definition is important because it directly relates to the governing body that makes decisions about the level of patient care in all facility spaces. A critical aspect of the new definition is that this body has the overall legal responsibility for the operation of the healthcare facility.517.2 Invasive ProcedureA new definition of the term “invasive procedure” has been added to 517.2 and includes any procedure that penetrates the protective surfaces of a patient’s body (i.e., skin, mucous membrane, cornea) and that is performed with an aseptic field. Note that not included in this category are placement of peripheral intravenous needles or catheters used to administer fluids or medications, gastrointestinal endoscopies, insertion of urethral catheters and other similar procedures. This revision aligns NEC Article 517 with the term defined and used in NFPA 99, Health Care Facilities Code.517.2 Patient Care SpacesThe defined terms under the main definition of “patient care space” have been revised, and descriptive informational notes follow each term. The revisions incorporate numerical categories 
(1 through 4) following each definition, and the bracketed information contains the location of the extract. The care locations within a healthcare facility are now defined as “spaces” and are each provided with a specific category that indicates the level of care under that designation. The revision aligns Article 517 with terms defined and used within NFPA 99.517.16 Use of Isolated 
Grounding ReceptaclesThis section has been expanded into two subdivisions. Subdivision (A) provides a clear prohibition of isolated grounding (IG) receptacles within any patient-care vicinity and is extracted from NFPA 99. Subdivision (B) provides allowable installations of IG receptacles that are outside of a defined patient-care vicinity. IG receptacles must be wired to meet the requirements in 517.13(A) and (B) and include an insulated copper equipment grounding conductor for the IG receptacle in accordance with 250.146(D). The wire-type insulated equipment grounding conductors are required, and the conductor installed for the IG receptacle must be identified with green insulation that includes one or more yellow stripes.517.29 Essential Electrical Systems for Hospitals and Other Health Care FacilitiesA new Section 517.29 has been added in Part III of Article 517. This provides information relative to types of essential electrical systems (EESs) required for Category 1 and Category 2 care locations. Subdivision (B) clarifies that critical care (Category 1) spaces shall be served only by a Type 1 EES. The type designations for the essential electrical systems in healthcare facilities are new to Article 517, and they align with the “Type 1” and “Type 2” designations included in NFPA 110, Standard for Emergency and Standby Power Systems.517.30 Sources of 
Power ExpandedThe required sources of power have been relocated from Section 517.35 to 517.30 for usability. Fuel cells are now included as a source of power for the essential electrical system, and it must be listed for that use. Subdivision (C) has been revised to remove the subjective phrase “careful consideration” and now clearly includes mandatory requirements for location of EES components and services.517.40 Essential Electrical System for Nursing Homes and Limited Care FacilitiesThe words “Type 2” have been added to the title of 517.40. The revision clarifies the type of EES required for nursing homes and limited-care facilities. The informational note assigns categories to the types of care in these facilities and provides the trigger for application of 517.29 through 30.600.2 Definitions and 600.34 
PV Powered SignsPhotovoltaic (PV) powered signs are now defined in 600.2 as a complete sign powered by solar energy consisting of all components and subassemblies for installation either as an off-grid, stand-alone; on-grid, interactive; or non-grid, interactive system. New Section 600.34 provides installation requirements for PV-powered signs.625.2 DefinitionsArticle 625 covers electric vehicle supply equipment (EVSE) and specifically addresses conductive charging and inductive (wireless) charging. Eight definitions are added to support new requirements for electric vehicle charging.Multiple new definitions are added to address wireless power transfer. These definitions mirror terminology used in SAE J2954, a standard that covers wireless charging of electric and plug-in hybrid vehicles. A new Part IV of Article 625 provides rules for wireless power transfer equipment.680.2 Electrically Powered Pool LiftsAn electrically powered pool lift is now defined in 680.2 as a lift that provides accessibility to and from a pool or spa for people with disabilities. New Article 680 Part VIII provides requirements for electrically powered pool lifts. Only the requirements in Part VIII of Article 680 apply to pool lifts. This equipment is required to be listed.680.7 Grounding and 
Bonding TerminalsNew Section 680.7, Grounding and Bonding Terminals, has been added and provides specific requirements for all grounding and bonding terminals. All must be identified for use in wet and corrosive environments and listed for direct burial use. Where field-installed in a damp, wet or corrosive environment, all must be composed of copper, copper alloy or stainless steel.680.11 Location of Underground Pool WiringRequirements from 680.10 for location of underground wiring have been relocated to 680.11. The prohibition of wiring within 5 feet of the pool is removed; all permitted wiring methods are listed. Former Table 680.10 for minimum cover depths has been deleted. Now, all underground wiring cover depths in the pool area must be in accordance with Table 300.5.690.12 Rapid Shutdown of 
PV SystemsSection 690.12 was significantly revised and separated into parent text and four first-level subdivisions. An array boundary is established with requirements for circuits outside and inside the array boundary. Three rapid-shutdown methods are provided for circuits inside the array boundary with an effective date of Jan. 1, 2019. The requirements for rapid shutdown of PV systems and equipment installed on buildings are in direct response to concerns expressed by first responders. Rapid shutdown provides responders with a method to reduce the output of PV systems to 30 volts within 30 seconds to allow for safe firefighting operations.690.56(C) Marking Requirements for Buildings With PV SystemsMarking requirements for rapid shutdown were significantly revised to warn emergency responders of hazards presented by a PV system and associated conductors. Two specific types of markings now address the type of rapid shutdown of the PV system and conductors in 690.12. Two new figures provide prescriptive and consistent detail in the required markings.691 Large-Scale PV SystemsLarge-scale PV electric power production facilities are covered by new Article 691. The number of large-scale PV systems is relatively small, but they generate more power than the combined output of all residential and commercial PV. To qualify for applying Article 691, all provisions in 691.4 must be met.A system is considered large-scale PV if it has a capacity of 5,000 kilowatts and is not under exclusive utility control. Only qualified personnel are permitted to maintain and operate these systems.695.3 Power Sources for 
Electric-Driven Fire PumpsA new informational note in 695.3 provides Code users with useful guidance for determination of reliability. NFPA 20, Standard for the Installation of Stationary Pumps for Fire Protection, has purview over fire pump performance and the reliability of the power source. Shutdowns, routine loss of power and overhead service conductors are identified as factors that would cause consideration that the source as unreliable.700.2 DefinitionsA new definition of “directly controlled luminaires” was added to 700.2. Article 700.24 was added during the 2014 revision cycle. It permits directly controlled luminaires as emergency lighting, but the term was not defined. These luminaires may be dimmed but must be driven to full illumination upon loss of normal power.700.3(C) and 701.3(C) MaintenanceSections 700.3(C) and 701.3(C) have been revised to require maintenance on all emergency and legally required system equipment. Electrical equipment in these emergency and legally required standby systems must be maintained in accordance with the manufacturer’s instructions and NFPA 70B, Standard for Electrical Equipment Maintenance.700.10(A) Identification of Emergency System WiringWhere boxes or enclosures are not encountered, exposed cable or raceway systems must be marked as a component of an emergency circuit or system at intervals not to exceed 25 feet. Receptacles supplied from the emergency system must have a distinctive color or marking on the cover plates or the receptacles themselves. The NEC does not specify a color, but red is often used.702.12(C) Power Inlets Rated 100 Amperes or GreaterA new Section 702.12(C) requires power inlets rated 100 amperes (A) or greater for portable generators in optional standby systems to be listed for the intended use. Power inlets must be equipped with an interlocked disconnecting means. Exceptions are included for inlet devices that are rated as a disconnecting means and for supervised industrial installations.Article 706 Energy Storage SystemsEnergy storage is becoming essential to meeting load-leveling capabilities along with demand response as it relates to smart grid initiatives and Department of Energy mandates on energy use. Associated and emerging technology coupled with the need for energy storage systems (ESSs) is growing rapidly, and new Article 706 provides requirements for ESSs in the NEC. Article 706’s scope specifically limits application to permanently installed ESSs over 50 volts (V) AC or 60V DC to correlate with existing requirements. This article correlates multiple other energy storage requirements in the NEC.708.10(A)(2) COPS Receptacle IdentificationNonlocking-type, 125V, 15- and 20A receptacles in buildings with critical operations power systems (COPS) and other power systems must have an illuminated face or an indicator light to signal there is power to the receptacle. All COPS-supplied receptacles installed where other power systems are present must have a distinctive color or marking on the cover plates or receptacles themselves so as to be readily identifiable.Article 712 DC MicrogridsNew Article 712 provides ­installation requirements for DC microgrids. DC microgrids eliminate power conversion resulting in more efficient use of renewable energy sources. DC power sources include AC-DC converters (rectifiers), bidirectional DC-AC inverters/converters, photovoltaic systems, wind generators, ESSs (including batteries) and fuel cells.725.144 Transmission of Power Over Limited Energy CablesA new Section 725.144 was added to address requirements for Class 2 and Class 3 circuits that transmit power and data to a powered device. Table 725.144 is new and lists permitted ampacities based on conductor types, sizes, number of cables bundled and ambient temperatures. Conductors that supply power for data circuits must be copper.(Note: if you as a Quora reader have actually read this far please let me know. I would be very surprised if anyone did.)728.5(C) Fire-Resistive Cable InstallationSection 725.5(C) has been modified to mandate that raceway fill for each system comply with the listing requirements for the system and not be greater than the fill permitted in Table 1, Chapter 9.Article 840 Part VI and 840.160A new Part VI in Article 840 addresses power over ethernet (PoE). Section 840.160 requires compliance with section 725.144 for PoE installations. A new Section 840.170 provides listing requirements for PoE power sources.