You may have seen electrical main panels that are mounted outside a home near the meter. Many of the older ones were installed here in central North Carolina during the 60s and 70s, when at least one power company was encouraging builders and owners to go “all-electric.” The main panel belongs to the power company that supplied the enclosure and breakers, gratis, as a bonus.
To remove the inside deadfront cover for inspection, the cover needs to be lifted slightly to get past obstructions, and then tilted out from the bottom to expose the panel’s interior. I always have assumed it is safe to remove and replace the cover because all electrified components would be protected by insulation or be at a distance from the cover so that one cannot contact anything live. WRONG!!
When I removed one such cover recently, the top edge was arc-burned where someone (still alive?) had shoved the cover high enough to contact the uninsulated 240-volt meter lugs. The design of this panel clearly creates a hazard for anyone handling the cover. Every exterior panel that I’ve seen since this incident has been designed to protect against this kind of short-circuiting. (Photo: Exterior Main panel, about 30 years old. Property of Duke Power Company.)
So much for my assumption that sensible people would not knowingly create an electrocution hazard. I advised my client and the homeowner of this hazard, left a sign on the panel, and recommended replacing the panel. Later, the power company repairman added tape along the top edge of the cover plate and penned this note: “Pull the meter from its socket before opening the panel.” That is an inadequate correction. Sorry, I’ll not pull the meter! (Photo: Cover plate has arc-burn damage where it contacted and short-circuited the exposed meter lugs.)
Since this happened, I look at the top of these panels with a flashlight to see what is there. If I do not see a hazard, I carefully lift the cover only slightly. I also use electrician’s insulated gloves, stand on an insulated board, and use a prop (not my hand, my head or my shoulder) to hold open the waterproof cover. It is safer to use a bungee cord or prop than for me or someone else to touch the waterproof cover. I ask observers to stand away, and I do not allow anyone to help me take the cover off or put it on. (Photo: Uninsulated meter lugs at the top of the main panel—showing arc/burn damage to lugs.)
In the book “Electrical Inspection of Existing Dwellings,” Douglas Hansen and his co-authors talk briefly about this issue, pointing out that the primary safety concern for the inspector is not electrocution, but rather the blast from the arc that could burn, blind or deafen him or her. Their advice: WEAR SAFETY GLASSES! (Photo: Duke Power "corrected" this safety/electrocution hazard by later placing insulating tape along the damaged edge of the cover plate.)
All photos courtesy of the author.