I was recently asked by a InterNACHI HI about what a thermographer who is conducting electrical infrared inspections in commercial facilities needs to be aware of with regard to safe work practices. I realize this may not be “on target” for all HI reading this board, but he asked that I post the information.
The relevant document is National Fire Protection Association (NFPA) 70E, Standard for Electrical Safety Requirements for Employee Workplaces, available from www.nfpa.org. The present version is a rather dry and ofttimes cryptic document but it does carry the weight of law in the US for anyone involved with electrical work, including thermographers. (I’m hopeful the next version in Q1-09 will be dramatically improved.)
The primary danger to thermographers is arc-flash rather than electrocution and the risk is not insubstantial as we are often standing right in front of energized equipment just after the enclosure has been opened. Arc-flash, which can happen on anything at 220V and up, occurs when current flows through air between phases or to ground; the result is an instantaneous explosion lasting a split second and producing temperatures in excess of 20,000C. If the energy involved is great, damage can be considerable including flash burns and blast damage—not pretty!
Essentially 70E says an employer is responsible, among other things, for (1) determining the potential hazards, especially with regard to arc-flash, (2) providing appropriate safety training, (3) creating safe written work practices, and (4) providing appropriate Personal Protective Equipment (PPE). The attached shows PPE typical for this kind of work but the exact PPE varies based on energy levels and needs.
If you are considering conducting these sorts of inspections (and many would argue that even the high side of a home panel presents these risks), I would urge you to get a copy of 70E and become familiar with it. There are also many good training courses available, typically 1-2 days, to round out your knowledge. To ignore 70E and arc-flash hazards is both dangerous and legally very shaky, especially if there is an accident.
All this may make home inspections look better than ever! Be safe—whatever you are doing today with your IR camera.
ASNT NDT Thermal/Infrared Level III #48166