Galvanized Rigid Conduit

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Old 01-03-06, 10:41 PM
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Question Galvanized Rigid Conduit

I'm putting a new meter panel on the side of my house and have to install a new riser made of galvanized rigid conduit (or IMC conduit, whatever that is). The GRC comes in ten foot lengths and is threaded on both ends for the weatherhead and the adapter for the panel. Problem is the pipe only needs to be about five feet long. I looked for a weatherhead or adapter that would just clamp on thinking I could just cut the pipe but I couldn't find any. Are those kinds of items available? Or how does this work otherwise?

Thanks.

Steve
 
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Old 01-04-06, 02:54 AM
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Galvanized rigid conduit

Steve: Check HD sku 327700. It is a 2 1/2" clamp on weatherhead. Is this what you are looking for? SKU 599788 is a 2". I've got the HD Pro CD, and it allows me to download current pricing from our local store. Pretty neat. Sadly, they are phasing it out for some reason. Couldn't do estimates at this hour without it.
 
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Old 01-04-06, 03:39 AM
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Or you could try a REAL electrical supply house. This is a very common stock item, in several sizes.
 
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Old 01-04-06, 10:10 AM
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Originally Posted by Speedy Petey
Or you could try a REAL electrical supply house. This is a very common stock item, in several sizes.
Awesome. I'll do that.

Thanks

Steve
 
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Old 01-04-06, 09:38 PM
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Called several REAL electrical supply houses and they all said they don't carry that kind of stuff. When I asked them where I should go they all said Home Depot. Sorry, Petey.

Hey chandler, got a SKU for a 1-1/2" clamp on weatherhead? I'm sure it's a special order item at HD but I can deal with that.

Thanks, guys.

Steve
 
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Old 01-04-06, 11:42 PM
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I know HD's plumbing department can thread pipe. Any reason you couldn't buy the 10' piece, and have D's plumbing department cut it to length and put threads on the cut end? Or would the threads be different?
 
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Old 01-04-06, 11:51 PM
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Maybe I'm showing my age. I didn't know they made weatherheads that DIDN'T clamp on. I've cut lots of risers and always put the weatherhead on the threadless end. HDs here carry every clamp-on weatherhead from 1/2" through 2".

IMC is Intermediate Metallic Conduit, which is not quite the walll thickness of RMC (Rigid Metallic Conduit), but approved for most uses, like risers. In fact, IMC is all they sell at our HDs.
 
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Old 01-05-06, 03:28 AM
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Bob, I am not doubting you but this sounds strange. In my area clamp on weatherheads are a totally standard item. Maybe Cali is different, I can't see why though.
I don't but much material from HD or Lowes so I can't vouch for them.
Good luck in finding something.
 
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Old 01-05-06, 04:46 AM
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Steve, the SKU for the 1 1/2" is 599751. Not to offend anyone, but the reason I use HD (and I use local lumber yards and electrical houses as well) is on certain items, they are selling the same items, made by the same manufacturers at a whopping lesser price. That is why I have their pricing program on my computer, to compare before I leave the house.
 
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Old 01-05-06, 07:31 AM
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The HD pipe machine makes NPT threads ( national pipe TAPERED). I thought that electrical conduit and fittings used NPS ( national pipe STRAIGHT) threads.
 
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Old 01-05-06, 10:00 AM
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D'Oh! You know, I'm an idiot. When Petey said this is a standard item I assumed he meant the pipe in different lengths which is what I wanted, instead of the clamp on weatherhead. That's what I asked for at the elec. supplies. I'll check to see what's available for clamp-on weatherheads.

Thanks.

Steve
 
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Old 01-05-06, 02:35 PM
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Originally Posted by 594tough
The HD pipe machine makes NPT threads ( national pipe TAPERED). I thought that electrical conduit and fittings used NPS ( national pipe STRAIGHT) threads.

594,

RMC and IMC both use NPT.

NEC
IMC 342.28 Reaming and Threading.
RMC 344.28 Reaming and Threading.

All cut ends shall be reamed or otherwise finished to remove rough edges. Where conduit is threaded in the field, a standard cutting die with a 1 in 16 taper (-in. taper per foot) shall be used.
 
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Old 01-05-06, 06:23 PM
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Check with your local power company to determine the proper size for your mast. Mine will not accept anything smaller than 2" dia.
 
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Old 01-05-06, 06:26 PM
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2" is a standard in most areas.
I do remember on Long Island it was 2.5" minimum.
 
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Old 01-05-06, 06:32 PM
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2" Rigid is only required if the service drop actually attaches to the mast.
 
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Old 01-05-06, 06:43 PM
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The term "mast" is generally accepted term for a riser that goes through a roof and/or has the service drop attached to it.
If the drop were not attached it would simply be a "service riser".
 
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Old 01-05-06, 11:22 PM
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i-1/2" rigid galvanized is what the utility rep told me to use when he came to the house to site the new meter box. At first he told me 1-1/4" RGC for a drop that was a bit shorter. It's about a 40' drop from the pole to a single story house and the riser has to be 36" above where it goes through the roof so I guess it is a mast. They're going to drop 4 gauge wires and supply the insulator for attaching the strain relief. I have to provide everything else and use 2/0 wire for the service drop to the meter as well as 2/0 to the subpanel but those are local requirements. Utility guy also gave me a diagram that looks very much like the one in Wiring Simplified showing all the required supports and dimensions.

Still have to get to HD to check out the weatherheads. Good to know about the pipe threads, though.

Thanks for everything, guys.

Steve
 
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Old 01-06-06, 11:17 AM
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The 36" above the roof is a minimum. Make sure the point of attachment for the drop is high enough to provide the necessary clearances from the ground for the service drop (12' over residential property and driveways).
 
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Old 01-07-06, 12:32 AM
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Yeah, I read up on all the requirements for the drop and there aren't any issues. I'm telling you the utility rep sited the location for the box, told me what size the riser needed to be, told me how high to have it over the roof, and gave me a couple sheets with diagrams of how to install the service. I'm just doing it how he told me to.

Still haven't made it to HD. Did plumbing all day at my brother's house instead. It was a good break.

Steve
 
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Old 01-07-06, 06:17 PM
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threads

Bolted: thank you for the reference on thread specs. I was simply relating what has been my experience. And today, I went over to HD and looked at the rigid conduit and the LB etc. fittings. They are all definitely straight thread. It seems this is one of those areas where code and real-world collide! From a practical standpoint, mixing tapered and straigt threads in electrical fittings would probably not cause any disaster. But I am familiar with unfortunate results when people mixed electrical pipe and fittings in a plumbing situation. The straight threads do not seal!

Not trying to pick a fight here. Just telling what I have seen. Doesn't mean what they do out here is right!
 
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Old 01-08-06, 12:26 PM
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Went to HD and, of course, ALL the weatherheads are clamp-on. Now comes the fun part of cutting through 1.5" of galvanized pipe.

Thanks for everything, guys.

Steve
 
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