Exterior panels mounted on plywood

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V

Vertex

Senior Member
In my area, it is common to find exterior surface mounted panels mounted to plywood on a stucco finished house. Sometimes the screws securing the panel pull through the plywood and the panel is hanging off the wall and only supported by the underground riser. It seems to me the best way to correct this problem is to drill a 1/2" hole through the panel and plywood and secure with a toggle bolt and fender washer. My only concern is that the NM home run cables behind the panel may be damaged by this method. What would you do?
 
J

johnwiles

Member
Vertex:

I believe that the plywood should be secured to the studs in the wall, and hopefully avoid any NM conductors running through the studs.
 
V

Vertex

Senior Member
Just to clarify, the NM home runs usually exit the panel through a 2" or 2-1/2" bushed KO on the back of the panel near the bottom. Once in the wall they immediately turn up to head for the top plate. They are subject to pass through an area where panel mounting hardware may protrude through the back of the stud-mounted plywood. For new construction not so much a problem because they can be seen. For repair, this may be a problem because the interior of the house is finished and the space between the studs where the wire races through can not be seen.
 
2

220/221

Senior Member
Location
AZ
A practice not allowed by the NEC
Click to expand...

We sometimes forget that the NEC isn't necessarily the "final answer".

Many local codes allow and disallow certain wiring methods.

For example, here, we aren't required to "attach" cables to the panel but we do have to install EGC's in conduit.

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To answer the question, drill some new holes and use short fat screws.....and tell them to start anchoring to studs or backing !!
 
V

Vertex

Senior Member
220/221 said:
We sometimes forget that the NEC isn't necessarily the "final answer".

Many local codes allow and disallow certain wiring methods.

For example, here, we aren't required to "attach" cables to the panel but we do have to install EGC's in conduit.

-----------------------------------------------------------------------

To answer the question, drill some new holes and use short fat screws.....and tell them to start anchoring to studs or backing !!
Click to expand...

Thanks for backing me up 220/221. And here's the proof.
http://phoenix.gov/DEVSERV/eleccode.pdf

BTW, get with the times. Shouldn't it be 240/241:grin:

What type of screw are you speaking of? 1/4"x1" lag bolt perhaps? That would still protrude through the other side of the plywood.

As far as telling "them" to do a better job anchoring, we are talking about the cookie cutter tract home ECs who have practiced this retarded method (sometimes using #10 screws) for decades. There is no way I could ever compete with these companies. Residential construction is so cut-throat. Also, I don't speak Spanish. At least they keep me in business cleaning up after them. Perhaps I should rename the company Janitor Electric.
 
2

220/221

Senior Member
Location
AZ
I was thinking along the lines of a #12 or #14 x 3/4" sheet metal screw. Drill holes carefully as to not drill out the plywood. Sneak some caulk or const adhesive in behind for extra holding power.
 
PetrosA

PetrosA

Senior Member
Location
Lancaster, Pennsylvania
As someone who hasn't even seen one of these outdoor mounted panels, I'm curious as to why they're mounted outdoors in the first place. What's the reasoning behind it, safety?
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
220/221 said:
We sometimes forget that the NEC isn't necessarily the "final answer".

Many local codes allow and disallow certain wiring methods.

For example, here, we aren't required to "attach" cables to the panel but we do have to install EGC's in conduit.
Click to expand...


From the looks of the pdf vertex posted your snap in bushing method is still a violation.:grin:
 
Buck Parrish

Buck Parrish

Senior Member
Location
NC & IN
PetrosA said:
As someone who hasn't even seen one of these outdoor mounted panels, I'm curious as to why they're mounted outdoors in the first place. What's the reasoning behind it, safety?
Click to expand...


If their is no place to install a panel where you would be back to back with the meter and inside panel. Or no basement to put the panel inside right under the meter .
Then it is cheaper to put it out side, and easier.
 
2

220/221

Senior Member
Location
AZ
As someone who hasn't even seen one of these outdoor mounted panels, I'm curious as to why they're mounted outdoors in the first place. What's the reasoning behind it, safety?
Click to expand...

Don't get out much? :D

1. Instalation is easier/cheaper because the all in one service is one piece of equipment and currently runs just about $120 for a 200 amp/40 space unit.

Stub your romexes out the wall, mount the panel over them and you are done. All wiring is secure and enclosed withing the structure.

2. Also, it doesn't take up valuable real estate inside.


From the looks of the pdf vertex posted your snap in bushing method is still a violation.
Click to expand...

Not necessarily. He just posted the wrong PDF. It's there, somewhere. I can guarantee it's not a 60 year old oversight. :roll:

And it's not MY snap in bushing. they are OUR snap in bushings :cool:
 
H

hillbilly

Senior Member
Any time I mount a exterior panel to a wood wall, I run the screws (or lags)
at a upward angle into the wood.

This allows the water to run off the screw instead of running into the wood, or accumulating against the hole in the wood.

That may sound kind of simple minded, but I've never had a panel fall off a house before, so there may be some benefit.:)

Just my opinion
steve
 
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