Working on finishing the basment and installed eps insulation on one wall so I can start to locate the position for a ew entrance service panel (up grading the old panel to new 200 amp service).
Located and started the 2×4 wall which will hold the new panel, so my question is, is it ok for the back of the panel to be next to the eps insulation?
Do I need something in between the two for fire reasons?
Thanks!
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Replies
The back of the panel must be separated from ANY combustible material by a suitable thickness of non-combustible material. That means your panel must have a suitable thickness of drywall behind it- you cannot mount it directly on EPS insulation, plywood etc. Others may correct me but I think you need at least 5/8" or two layers of 1/2" drywall.
If you want to keep a layer EPS on the wall behind the panel, it might be best to cover the EPS with a sheet of plywood larger than the panel (to affix your wire staples), then to put the required thickness of drywall between the panel and the drywall when you install it. Make sure the plywood is solidly fastened to the framing or the wall behind.
"The back of the panel must be separated from ANY combustible material by a suitable thickness of non-combustible material. That means your panel must have a suitable thickness of drywall behind it- you cannot mount it directly on EPS insulation, plywood etc. Others may correct me but I think you need at least 5/8" or two layers of 1/2" drywall."I want to see that in the NEC. Most all of my panels touch, screw, or nail to wood. Typical flush mounting is screw panel between two studs. Studs more than 14 1/2" apart? Shim with wooden shims. Mounting a panel on a masonary wall? Lots of time I mount a 3/4" plywood panel to the wall first and then mount the panel. Makes neat running of romex, gives a stapeling surface. Also gives the panel a thermal break from the masonary wall. The only item relating to combustable surfaces and panels/boxes is that the combustable material cannot be inside the box i.e. a switch/receptacle box mounted with more than 1/8" gap behind a wood wall. Need a box extension to pass code.4Lorn, et all.... what do you do?Frank DuValYou can never make something foolproof because fools are so ingenious.
Looked through my IRC book and did some searching on the net last night and could not find specific information about contact or noncontact eps behind the panel. I did find a sight that stated to put R-10 foam board behind the panel to insulate it when in an outside wall, but I don't trust everthing I read on the net (except for you guy's that is!)
My old panel, and my father in-laws new panel(put in by the pro's and inspected) is mounted in his basement on 3/4 plywood to a inside block wall.
Right now my panel is mounted between the studs(temporary) and has a 1/4 to 3/8 air space from the eps, I will most likely move some thing around and put at least some ply between the two.
Thanks for your help
I apologize. The Canadian Electrical Code definitely requires drywall or other suitable non-combustible material behind the panel, but this rule may not be a requirement of the US NEC. There are differences between the two codes. But it does make sense to have that drywall layer beyind the panel regardless. EPS is very flammable and codes up here require it to be covered by low flamespread materials everywhere, not just behind a panel.
Edited 1/18/2006 9:21 am ET by moltenmetal
Actually, I think the latest version of the CEC removed the requirement for drywall and the like behind a panel. I installed a new panel for the house and due to the change, just mounted it to plywood. Inspector had no issues with it.
Just had a thought, since it is in the basement, dry now but still a chance for some moist. What if I used some 1/4" cement backer board behind the panel over the eps. The panel would not be in contact with the backer board since its mounted between the studs, maintaining a airspace and it would be a fire barrier to the eps and water resistant.
Hi Moltenmetal,At least in Ontario, Snipes is correct and the electrical code no longer requires drywall behind a panel.
In case you're interested, I've pasted the text below from the FAQ section of the Electrical Safety Authority website http://www.esasafe.com/consumer/esafaqs.htm
Regards,Ewan
Question
What materials are suitable for mounting an electrical panelboard on? Is drywall required behind the panel or can it be mounted on plywood?
Answer
The Code states that a panel board must be firmly secured to studs, joists, or similar fixed structural units. The Code no longer requires drywall to be installed behind the panel. Plywood or similar material such as chip board is often secured to structural units to provide a firm flat backing to which the panel can be mounted.
If the panel is mounted on a wall separated a heated area from a non-heated area, then sufficient thermal insulation and vapour barrier as required by the Ontario Building Code must be installed between the panel and the wall.
Ontario Electrical Safety Code Rule 12-3012.
Excellent. Thank you for the update- I do appreciate it! The Electrical Safety Authority's website has been very helpful- both the FAQs and the Q&A service they offer. It's unlikely I would have learned that I hadn't posted to the OP's question and you hadn't replied. That's why I come here.
Personally, I'd want something, whether that be plywood or something even less combustible, between the back of my panel and a piece of highly flammable EPS foam.
Edited 1/18/2006 1:18 pm ET by moltenmetal