Insulation behind panel.

Yes but a good practice is to leave it 3" away to allow heat to escape the panel.

It seems that if the panel is getting so hot that insulation is a problem, then something is so seriously wrong within the panel that lack of insulation won't help.

Heat is a natural byproduct of electricity. Having a panel warm up is not uncommon nor is it an absolute indication of a problem.

No it is not. Heat is the "byproduct" of power. There shouldn't be any significant power dissipated by the panel (and contents). Don is correct; if the panel is hot it's not because there is insulation around it.

Then I'm guessing you've never walked into an electrical vault, seen all of the exhaust fans running and still sweated your tail off?

No, my "electrical vault" is too small to walk in. What a maroon!

There are always some losses across breakers etc. This relates to generating warmth, the bigger the current the more heat. I would not expect much heating in domestic equipment, I suspect Rich is talking about industrial or large building installations and he is right about the warmth generated in those installations, it is a normal situation.

Rheilly P

It appears that the vault in question contained transformers which are the source of heat, rather than the switchgear which really should produce negligable heat. A far cry from a household distribution panel.

The closest thing to an electrical vault I've been in was in an office building, and it was indeed hot in there and had a fan, but there was a huge (by my standards) transformer in there humming away which was the obvious source of most of that heat.

I've felt circuit breakers in a residential panel that were warm to the touch, but if anything struck me as *hot*, I'd be very concerned.