Panelboard Mounting on Gypsum - Allowed?
Panelboard Mounting on Gypsum - Allowed?
(OP)
I have a project where the contractor is attaching panelboards (42ckts) to gypsum board walls using toggle bolts. For reinforcing purposes they are placing blocks of wood between the panelboard and gypsum wall. Is there any code that disallows this? The project is located in Delaware.
NEC 110.13 and ANSI/NEMA PB1.1-2007 only state that they shall be "firmly secured" and "reliably secured" to the mounting surface. I have also talked to Siemens and nothing in their packaged installation instructions talk about how the panels should be mounted.
Thanks in advance!
NEC 110.13 and ANSI/NEMA PB1.1-2007 only state that they shall be "firmly secured" and "reliably secured" to the mounting surface. I have also talked to Siemens and nothing in their packaged installation instructions talk about how the panels should be mounted.
Thanks in advance!






RE: Panelboard Mounting on Gypsum - Allowed?
It's done with old work outlet boxes all the time, but I would not be comfortable doing this for a panelboard. Is this is 20" panelboard or a smaller residential loadcenter?
I would want the box supported by the structural members in the wall. I'm not sure I see how the blocks of wood are helping much.
There must be a story behind this.
David Castor
www.cvoes.com
RE: Panelboard Mounting on Gypsum - Allowed?
ANSI/NECA 1-2006 and other ANSI-approved installation standards. Now that is as clear as mud.
But almost universal practice in the USA is to attach a fire rated plywood on the gyp board and then screw the panelboard on them. I would think anything less than that (barring recessed installation) would be considered un-workmanlike!
Rafiq Bulsara
http://www.srengineersct.com
RE: Panelboard Mounting on Gypsum - Allowed?
No known code requirement - just good practice.
RE: Panelboard Mounting on Gypsum - Allowed?
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David Castor
www.cvoes.com
RE: Panelboard Mounting on Gypsum - Allowed?
RE: Panelboard Mounting on Gypsum - Allowed?
We are most likely going to state it is not Good Workmanship but would like something more solid such as a standard. The project is new construction so there is no reason not to have structural framing for support.
I do not have access to NECA 1 either. I believe the CTR is not hitting studs because in a couple cases we have 2 or 3 panels mounted next to each other and before the gyp board went up the CTR must not have installed horizontal bracing. Using 4 toggle bolts to hold up a 200+ panel is definitely not good workmanship.
RE: Panelboard Mounting on Gypsum - Allowed?
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If it is broken, fix it. If it isn't broken, I'll soon fix that.
RE: Panelboard Mounting on Gypsum - Allowed?
RE: Panelboard Mounting on Gypsum - Allowed?
The fact that they have the wood blocks in between already shows that they know it is not sound and also means there's no problem with it being shimmed out from the gypsum by the distance necessary for some structure beind it.
RE: Panelboard Mounting on Gypsum - Allowed?
Pics: (copy and paste into your browser if necessary)
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The manufacturer installation instructions that come prepackaged with the panels refers to standards for installation such as the NEC and PB1.1. This is the case for Siemens panels. I am not sure about other manufacturers.
Thank you "ccjersey." You make a very good point that if the contractor is placing wood blocks in for support then the contractor must know that drywall is not the best support. Either that or they cracked enough drywall when inserting the toggle bolts they needed extra support. The second picture above shows a toggle bolt basically ready to fall out of the wall.
Our specs also call for surface mounted enclosures to have a 1/2" gap between the wall and the contractor is violating this also. This would be a great place to have unistrut installed. This would add structure and support and fulfill our requirement.
It looks like I am going to have to pursue "Good Workmanship" and the 1/2" gap standard we require to get this installation in order.
RE: Panelboard Mounting on Gypsum - Allowed?
BUT, with metal studs I would suggest that as well as being bolted to the studs, backing strips be installed between the studs.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Panelboard Mounting on Gypsum - Allowed?
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RE: Panelboard Mounting on Gypsum - Allowed?
NECA 1 states:
Section 10. Equipment Mounting
"a) The fasteners or supports shall be sufficient to substantially secure the equipment in place to the building structure or structural element."
Gypsum board is not a structural element (merely aesthetic) therefore should not be used as a support for equipment. Unfortunately our specifications do not reference this standard. In the end, the AHJ has the authority to make interpretations of the rules listed in the NEC and the neat and workmanlike manner sits under this approval.
We have come to an agreement with the contractor to provide unistrut framing behind the panels but I will be sure to add this standard to our specifications and plans.
Thanks again to everybody.
RE: Panelboard Mounting on Gypsum - Allowed?
Thank you for the feedback and I am glad that an amicable solution worked out for you.
Rafiq Bulsara
http://www.srengineersct.com