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Joined: Jul 2002
Posts: 241
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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.
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Joined: Oct 2001
Posts: 597
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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.
Al Hildenbrand
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Joined: Dec 2001
Posts: 444
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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.
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Joined: Mar 2002
Posts: 53
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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.
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Joined: Sep 2002
Posts: 11
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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...
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Joined: Dec 2000
Posts: 4,294
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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.
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Joined: Jun 2001
Posts: 196
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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]?
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Joined: Jun 2001
Posts: 642
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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.
ed
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Joined: Oct 2000
Posts: 5,392
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I'm surprised there has not been a marketed panel 'backboard' .....
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Joined: Oct 2000
Posts: 4,116 Likes: 4
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I don't think I have ever seen a rotted Backboard. We always used 3/4 Plywood with Remington power fasteners.
Bill
Bill
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Posts: 264
Joined: February 2013
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