Here on Long Island, on a residential service there is normally a plywood(3/4") backboard secured to the foundation wall. What I have done in the past would be to paint the plywood first with 2 coats of weather proof paint, and then power nail it to the wall. Does any one have another method or style to put a service panel on a foundation wall?

Use TAPCON masonry screws to secure the panel directly to the foundation wall.

Chris

My complements on putting in the extra work to paint the board.

Ditto on the Tapcon suggestion.

There are a lot of unpainted backboards used throughout this 7 country metro area of ~3 Mil souls. Only occasionally do I see a painted one. Ironic. Your thread happens just after I put the first coat on a 4 x 4 sheet that I'll use on a custom job, a job that is paying extra for the quality.

Al

Well, once upon a time, I was told that the backboard had to be "black",. (Fireproof paint) Well it was flat black latex! So he lied.
Now, we use wood stain. Black or dark gray.
For the "cusom" jobs, we have used epoxy paint. We also found a nice "edge guard", to cover the edges. It's a plastic "U" that slips over the edges of 3/4" plywood. Miter cut the corners, and you can do it in 1 piece. Mess up, and you can do it in 2 pieces. Mess up real bad, 4 pcs, and a few ss screws.

Anyone else ever heard of the "fireproof paint???
John

We're supposed to use fire-treated 3/4" plywood(rarely happens). But I usually make one of the GC's laborers at least paint it grey, I thought that was the norm. We use the smash-in anchors now from Hilti to hold it up.

[This message has been edited by CanadianSparky (edited 10-07-2002).]

We use masonary anchors directly to the concrete or block. In this area only the meter is outside. The main is in the panel directly inside (10') of metal conduit is max length between meter and panel.
Why put wood on concrete or block if the rest of that wall is bare? the wood will rot out before the masonary.

[This message has been edited by nesparky (edited 10-08-2002).]

I use pressure treated 2X4's mounted to basement wall with plywood on that. Not much chance of anything rotting out.

NESparky,

In my experience, the fasteners fail before the wood. I'll find 60 year old services on "one bys" that are held in position by the mounting screws of the panel, with, maybe, one or two of the original masonry nails left in service. The masonry gives way. The wood and the box are OK. Panel and sub panels are held in position by the wood, not stressing the panel-conduit-panel bonds as badly as if they were hanging only by their raceways and cables.

Another value of the backboard is as a thermal break to help minimize condensation; and as a moisture barrier to prevent corrosion. Most older dwellings around here have basements, and the below grade masonry will dampen when covered even when the basement is experienced as "dry".

Lastly, if there is enough moisture to take out the wood, it'll take out the panel anyway.

Al

How about mounting panel on 1 5/8 unistrut. Fasten unistrut to wall with tapcons and use spring bolts and 3/8 bolts w/washers to hold panel. That's the way I have done it. Also allows you space behind panel to run conduit if need be.

The unistrut idea sounds good and strong. My friend paints both the front and back of the plywood 3/4" backboard, and I thought I got into it with just painting the front of the board.

I'm partial to 3/4" ply sandwiching 2" rigid insulation and held in place with countersunk 4" phillips concrete screws. I'll put nine in a 4' x 4' sheet. The oversize backboard helps to hold the place for the required workspace as well as being convenient for other use.

For a few years now, the Canadian E.C. required us to use min. 1/2" drywall between the panelboard and the plywood, but for 2002, that code requirement was dropped.

We have never painted any substrates we have used. The backboard is used primarily as a spacer for our pipe to enter panel straight.

A lot of times it ends up being one or a combo of the following: plywood-1/2, 3/4, one 2x4, two 2x4.

A 2" 90 7" center over a foundation usually ends up being a 3" spacer for the panel to get pipe in straight.

We always cut our backboards/spacers so that it will end up a 1/2" short on all sides, that way you really don't see any of it.

On residential sites wood is usually available. For any commercial jobs, typically a unistrut set-up has all the advantages of setting up a clean, and or multi-layered conduit layout.

SJT
I have found that fire rated plywood is just fine and the inspectors love it. Although it costs a touch more if you buy a full sheet you should be able to get 7 panels out of it. I am also a Long Island contractor...

Here in SoCA, fire rated plywood is the thing for backboards, whether they be for electrical, phone, or data.
A 4X8 sheet of 3/4" runs about $55.
I've run into some problems in the past with painters very professionally covering the rating label. Now I just screw a couple of 4S blank covers to cover the label, and let them paint away, removing the blanks when they're done.

what code section is used to require the fireproof backboard? or is it just good practice? and if it's cut into pieces, then how do they know it's fireproof? is the labeling every few inches[oops, millimeters]?

I have had about 5 service change outs that had the old panel on wood backboards. All had rotted wood. Have yet to have masonary/ concrete rot out. Not all the block walls were as good as new but have not had any trouble mounting the new panel on the walls. Usually use lead set type anchors to mount the panel Sometimes am able to re use those type of anchors if the screws have not rusted.
Of course differenr areas have different work practices depending on local factors.
Almost all resi panels are in the house here only the meter socket is outside.

I'm surprised there has not been a marketed panel 'backboard' .....

I don't think I have ever seen a rotted Backboard. We always used 3/4 Plywood with Remington power fasteners.

Bill

sparky
I saw an ad for a backboard for meter cans to be installed on before the siding is installed.The same co.may have something for panels,but I don't remember the name.Anyone else?

Arlington?

[This message has been edited by Bill Addiss (edited 10-13-2002).]

Bill ,that sounds right. My Alzheimers was kicking in again

Yes, Arlington makes the meter mounting board. It's the MM series.
BTW,

They make a larger unit (MM 35?) that my local suppliers didn't carry. I would have needed to order a minimum quantity. I called Arlington and they sent me one free of charge!

I'll have to try treated 2x4's secured to the concrete first, then the painted plywood (3/4") over that. It sounds like a real nice job.

If the areas you are mentioning are in a wet or damp location, and I would consider a basement in some cases to be wet and damp, then Art 384-17 (1999 Code) refers you to Art 373-2(a). That requires a 1/4" airspace between the enclosure and the wall.
Our company specs require a unistrut channels run vertical behind the panel. This allows busbar cooling by venting the air upward as in the chimney effect. It also eliminates the possibility of moisture buildup on the back side of the enclosure.

Hello Warren,
What area is that? Sounds like a good rule.
Stay safe

Most older service cutouts and meters in England are also mounted on ply, although not normally painted.

The older ones were fitted to the wall with four porcelain standoffs giving about 5/8" clearance behind.

The new outside plastic cabinets have particle board secured in the back.

I'm surprised there has not been a marketed panel 'backboard' .....


A local company is making backboards up here in Maine. Consists of plywood and 2 by 4's painted black. I forget the price and sizes?. They used to have a display in the supply house I frequent the most.

I use PT 2x4s on the flat with concrete nails and then secure the 4 x 4 sheet of 3/4" AC Ply to the 2x4s.