The salts found in concrete, and its ability to wick moisture will corrode the panel. I recall a discussion about this issue in 2nd-year school. I can't find anything in the CEC book though.
The 'fireproof' requirement may be referenced better in the Building Code. I have seen fire-resistant and painted regular plywood used for the purpose (perhaps fire rated paint satisfies the requirement?)
#102283 - 12/27/0510:45 AMRe: Why switches,panel should be mounted on wood?
We use plain plywood when mounting our stuff to concrete. No special treatments required. A few years ago, they required drywall in between the panel/switch and plywood, but last few years they eliminated that rule as the panels and switches are "enclosed" and supposed to suppress any fire. Hey, I don't write the codes, good enough for me.
#102284 - 12/27/0502:43 PMRe: Why switches,panel should be mounted on wood?
Interesting,we never use anything in industry.Bolt everything directly to concrete or block.To be honest Ive never looked for it in the code.Is it a damp location issue.The only time Ive seen wood is to have something to screw to for phone equipment etc.In not saying you don't need it.i just want to know the circumstances and where its applicable.Code rule # anyone cheers
#102285 - 12/27/0507:49 PMRe: Why switches,panel should be mounted on wood?
Frank...yes, to clarify, for individual switches, we bolt directly to concrete/block. But typically, when we do a service from scratch, with main switches, mb, splitter, panels, etc. I like to use 1 or several 4x8 sheets of plywood. So much easier/faster screwing into wood.
#102286 - 12/28/0503:13 PMRe: Why switches,panel should be mounted on wood?
I have always used plywood to mount equipment wherever I am also using loomex to wire (resi mostly). I work industrial now and it is the same as what Frank stated,everything straight on to the concrete or block.I have never taken fireproofing into consideration and have never had a violation for doing it this way. Who knows maybe I have been missing something but I can't check for code rules as I am in a hotel in Winnipeg with no code book.(What was I thinking..lol)
#102287 - 12/28/0505:46 PMRe: Why switches,panel should be mounted on wood?