Electric Shock and Electrical Burns

The 12.5% of the test on Codes and Standards includes the NEC, National Electrical Safety Code (NESC) and Electric shocks and burns. I already went over the NEC so today it was on to shocks and burns.


Electrical shocks and burns is really the domain of NFPA 70e: Standard for Electrical Safety in the Workplace, and if you want to learn how to do Incident Energy and Flash Protection Boundary Calculations, Annex D of NFPA70E is a good resource, but if you don't feel like reading through all that and just want to familiarize yourself with the subject, Mike Holt has a short article on Electric Shock and a longer one on Electrical Burns.

I'm not really sure what kind of questions the NCEES will ask on Electric shock and burns. I could envision a question on calculating arc flash protection boundary distance question or a maximum safe shock duration.

• Calculating Arc Flash Protection boundary distances is straight out of Annex D of NFPA 70e
• To determine the maximum safe shock duration according to IEEE Std. 80, you can use the formula, T=0.116÷(E÷R), where T is duration in seconds, E is the electromotive force in volts, and R is resistance of the person, which is a constant 1,000 ohms.

Ugly's has a handbook for Electrical Safety and NFPA 70e which has some calculations in it that mirror Annex D. Google books has a preview of it which gives you a free 20 or so pages.

NEC digest also has a good article on PPE person protective equipment and burns

NEC Code Review

Yesterday I attended an all day seminar on the 2011 NEC code which was a good review of how much of the code I don't normally use and need to freshen up on. The PPI book is only a brief survey of what topics the code covers and doesn't actually prepare you to answer code related questions so I went in search of something that would force me to go through a bunch of NEC problems. Tada, Mike Holt the NEC code guru comes to the rescue. He has free online quizzes for the 2002, 2005 and 2008 NEC. It randomly quizzes you on 10 NEC code questions and then gives you the section with the right answer if you mess up. It has 1900 different questions and it reloads different questions each time you open the quiz. If you want the full quiz all at once with all 1900 questions you can buy it for $25. Mike, you rock as always.

Mike Holt Free 2008 code quiz

Other free Mike Holt goodies:

• Quick guide to conductor sizing
• Electrical formula sheet
• NEC 2008 Index - Saves time using the actual Index by cutting to the good stuff
• Wiring & Raceway Chart