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Thread: Conduit on ground
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10-19-2009, 02:39 PM #1
Conduit on ground
I encountered this today at a commercial building. The service was upgraded to 400A recently. The conduit was run down and along the asphalt/building line. On the other end it is run up then through the wall where it enters at about the 9' level then down again to the service panel. There is access to the flat roof which is where I would have expected the conduit to run. Is there anything wrong with this installation? It passed county inspection but that means little here. Astetically it is unsightly and by the time I left the site the conduit had collected/trapped leaves. This is also an area that may or may not be plowed. It will definately be an area that will be shoveled (snow) during the winter months. Will you share your thoughts/comments?
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10-19-2009, 06:15 PM #2
Re: Conduit on ground
This a bad install with no common sense. It leaves itself open to corrosion and damage especially if a snow plow comes along. Seems like he ran out of fasteners so desided to put it on the ground. Who knows? Please somebody help me understand!
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10-19-2009, 06:23 PM #3
Re: Conduit on ground
This looks like rigid conduit (GRC) and if so it is approved to be run in areas subject to damage, as is the case here. Looks to me like a good install for the most part.
The issue I have with it is that the conduit needs to be set so it doesn't sit in water and I can't tell from the picture if the conduit actually rests on the asphalt or if there is a small space under it.
As to running conduit across a roof, that's the last place I'd put any wiring if I had any choice in the matter. Too many issues.
A second look under a bit of magnification shows what appears to be single hole straps mounted on the top, so while the conduit is sitting on the strap and not the asphalt the strap is probably is on the asphat.
Last edited by Bill Kriegh; 10-19-2009 at 06:38 PM.
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10-19-2009, 06:47 PM #4
Re: Conduit on ground
Conduit/strap is resting on asphalt. Either one on ground is subject to remaining in water. Another issue is regarding a possible future egress being installed. Running the conduit above on the wall surface is not an option due to the water runoff system (downspouts). It must be run behind the roof lip (set on pressure treated lumber) then back down entering building in same fashion as it currently enters.
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10-19-2009, 06:50 PM #5
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10-19-2009, 07:22 PM #6
Re: Conduit on ground
Bill,
You mean RMC?
Those adapters and couplings look more like EMT ones, they look like compression fittings.
If it is EMT, then it is not rated for protection from "severe physical damage" (note that there is no definition for "severe physical damage" as compared to "physical damage").
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10-20-2009, 02:17 AM #7
Re: Conduit on ground
Yeah, GRC is local supply house speak for RMC. I forget sometimes.
I'd think that the hex shaped ends of a compression fitting would show up better if present, but if the conduit is EMT it doesn't belong there. Most AHJs I'm used to dealing with have a rule of thumb that conduit from ground level to around 8 feet above ground is subject to excessive damage and want RMC or Sch 80 PVC and I think that's pretty reasonable.
I still see the straps on the asphalt as the only issue here.
Mounting the conduit on lumber isn't an option - that''s hack work and unnecessary. As to accounting for a future egress, my experience in commercial work is that you deal with the existing conditions. You deal with door issues if and when somebody wants one. I'm sure that whoever bid this job got it because they were low bid and nobody else considered building a trapeeze to run the material around downspouts in a bid. "Course if you want to toss in the extra bucks all bets are off. I'm certain somebody could build strut brackets and hang the stuff far enough off the side of the building to get around the downspouts while providing ample nesting opportunities as a bounus, Hell, the downspout guys didn't consider the possible future electrical work here. Maybe the asphalt shouldn't be so close to the building so the stuff could have been buried.
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10-20-2009, 07:39 AM #8
Re: Conduit on ground
You mean like this zoomed in shows?
Most AHJs I'm used to dealing with have a rule of thumb that conduit from ground level to around 8 feet above ground is subject to excessive damage and want RMC or Sch 80 PVC and I think that's pretty reasonable.
That comes from 300.4, 300.5(D)(1) and 300.5(D)(4) (which addresses "subject to physical damage" and not even "severe physical damage").
Last edited by Jerry Peck; 10-20-2009 at 07:46 AM. Reason: uummmmm ... forgot to add the photo ... duh!
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10-20-2009, 10:51 AM #9
Re: Conduit on ground
I was looking at the stuff on the ground. The picture shown enlarged could be either - they do make compression fittings for RMC.
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10-23-2009, 06:10 AM #10
Re: Conduit on ground
I like it - it's a clean instal, and placed well out of harm's way. "Out of sight" as well - it's barely noticeable, and I'm sure cosmetic considerations influenced the placement. (Hang it on the wall, and it's as obvious and ugly as can be). We'll get back to the issue of anchoring it in a bit ....
First, I'd lay odds that it's EMT, though, as already noted, there are compression connectors for RMC. (And, yes, the supply chain calls it GRC, for 'galvanized rigid conduit). I think it's bent EMT; the joints don't seem to line up with factory 'sweeps,' and bendidng rigid that size is out of the range of most shops.
As for the likelihood of damage, right there at the meeting of wall and grade is a little 'bubble,' an area that's pretty much out of harms' way. To use the snow-plowing example, it's more likely to have a plow further protect it with a berm of ice, than it is for the blade to strike it.
Moisture and such pooling under it? That's where the idea of placing the pipe down there runs into some issues, but not the ones you might expect. The ground is almost never smoth and flat, leaving plenty of places for water to drain. There's also a seam at the building face that will drain. The issue arises when the ground is uneven and not perfectly level; then the pipe won't lay right. There's also the issue of strapping the pipe.
Strapping the pipe is a real challenge; you don't really have the space you need to work, and most strapping methods also provide places that will stick out - catching on things. You have to decide whether to attach it to the wall or the pavement, not both.
I am a bit concerned about the open meter faces. Those cardboard pieces just won't do for any lenght of time, once the bases are energized. That looks like a new transformer as well; there's some work going on.
If I were checking this instal, there are easily a half-dozen thing's I'd worry about before I got around to looking at the route the pipe takes. Thats WAY down my list of priorities here.
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10-23-2009, 11:02 AM #11
Re: Conduit on ground
I would much rather see it where it is then on the roof.
Running conduit on a roof is a last resort if you ask me.
On the roof you need to deal with; temperatures, expansion/contraction, how to secure it, and the added expense of moving it for roof replacement.
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10-23-2009, 12:03 PM #12
Re: Conduit on ground
John, great post, and I totally agree.
I would not worry about the cardboard. That is typical around here. In fact the meters I buy have a kind of waxed cardboard cover like that. The meter will NEVER see power with just the cardboard there. The POCO will see to that.
The cardboard is there just to keep dirt and junk out until the meter is set.
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