PVC service masts

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arnettda

Senior Member
Can I use schedule 40 PVC for my service mast? Or does it need to be schedule 80? All i see is 230.28 which talks about service masts used as support. My mast will not be used for support. Is my TA screwed into the top of the meter hub allowed as well? I am questioning the glued portion where the pipe goes into the T.A. Thanks
 

infinity

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The PVC into the TA is not an issue but technically the TA into the hub is not permitted. SCH40 can be used if not subject to damage. I would call this a service riser not a mast.
 

augie47

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You might make note to strap it in a manner that allows for expansion per 352.30
 

infinity

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You might make note to strap it in a manner that allows for expansion per 352.30
Some inspectors around here do not allow metal straps for this reason. We had one POCO that said if you go underground they require metal straps on the pole but the EI wouldn't allow them on the building. :rolleyes:
 

Little Bill

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This would be a POCO rule. Here, if we use PVC, it can't penetrate the roof or soffit. The point of attachment has to be solidly attached to the framing. Most want eyebolts with nuts & washers on both sides. Some will allow strong lag bolts if there is enough "meat" to screw into.
Sch 40 or 80 depends on POCO requirements. We have some that require 80 and others don't care.
 

arnettda

Senior Member
The PVC into the TA is not an issue but technically the TA into the hub is not permitted. SCH40 can be used if not subject to damage. I would call this a service riser not a mast.
What is the issue qith the TA into the Hub? is it a type of thread thing?
 

infinity

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What is the issue qith the TA into the Hub? is it a type of thread thing?
That's correct. UL has stated that the hub is only listed for RMC and IMC. IMO it's ridiculous because 95% of all services around here are either PVC or SE cable into the hub. Around here no one enforces that.
 
That's correct. UL has stated that the hub is only listed for RMC and IMC. IMO it's ridiculous because 95% of all services around here are either PVC or SE cable into the hub. Around here no one enforces that.
So I believe the work around is a RGS nipple into the hub and a PVC female adapter (theoretically, I also just thread the TA into the hub and have never been questioned).
 

infinity

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So I believe the work around is a RGS nipple into the hub and a PVC female adapter (theoretically, I also just thread the TA into the hub and have never been questioned).
That is one way of doing it to get around the bonehead UL thingy. Completely stupid in my book for someone to require you to do that instead of screwing the TA directly into the hub.
 

wwhitney

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That is one way of doing it to get around the bonehead UL thingy.
Is the bonehead UL thingy just about grounding and bonding? In that case it wouldn't matter for a PVC TA, vs say an EMT connector.

Or is it also a mechanical integrity thing? I.e. the combination is required to understand some mechanical testing, but nobody has done the testing for that combination?

Cheers, Wayne
 

arnettda

Senior Member
That's correct. UL has stated that the hub is only listed for RMC and IMC. IMO it's ridiculous because 95% of all services around here are either PVC or SE cable into the hub. Around here no one enforces that.
My Package for my Milbank Hub says threaded rigid conduit. Could this be Rigid Polyvinyl chloride Conduit PVC?
The cut sheets say NPT thread type 8 threads per inch. PVC T.A. have what type pf thread?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
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Henrico County, VA
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I'm 99% sure they mean metal conduit. I've never seen PVC conduit threaded.

(Yes, I know you mean a male adapter, which normally has a straight thread.)
 

arnettda

Senior Member
I'm 99% sure they mean metal conduit. I've never seen PVC conduit threaded.

(Yes, I know you mean a male adapter, which normally has a straight thread.)
I would agree that the male adapter is not threaded rigid conduit. And thanks for the info on straight threads.
 
I'm 99% sure they mean metal conduit. I've never seen PVC conduit threaded.

(Yes, I know you mean a male adapter, which normally has a straight thread.)
Actually they are not straight threads on a TA. This came up in a recent thread. Can't remember who it was who said they were tapered, but I was skeptical so I got the dial calipers and they were indeed (although according to my measurements somewhat less than standard pipe taper).
 

tom baker

First Chief Moderator
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This would be a POCO rule. Here, if we use PVC, it can't penetrate the roof or soffit. The point of attachment has to be solidly attached to the framing. Most want eyebolts with nuts & washers on both sides. Some will allow strong lag bolts if there is enough "meat" to screw into.
Sch 40 or 80 depends on POCO requirements. We have some that require 80 and others don't care.
We use a snuggle plate, a metal plate with holes for 6 lag bolts and a insulated thimble for the drop.
 

wwhitney

Senior Member
Location
Berkeley, CA
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Retired
Actually they are not straight threads on a TA. This came up in a recent thread. Can't remember who it was who said they were tapered, but I was skeptical so I got the dial calipers and they were indeed (although according to my measurements somewhat less than standard pipe taper).
The one time I looked it up, it varied by diameter, 1" and under are tapered but over 1" was non-tapered. Or vice versa. Assuming I remembered the break point correctly. I checked a couple common manufacturers, not hard to find the info.

Cheers, Wayne
 

goldstar

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Location
New Jersey
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Electrical Contractor
You might make note to strap it in a manner that allows for expansion per 352.30
I once had 2-hole PVC straps on a 2" PVC riser for a 200A service. It was in direct sunlight and after 1 year most of the straps snapped off. Fortunately, the one at the top near the weather-head didn't. I went back and replaced them with 2-hole metal straps. I know it's not Code compliant but the CMP's making these rules are not out here in the field installing these services (maybe they did at one time and forgot what it's like). I don't know if they realize that we're not installing T-stat wire inside these conduits. :) For the record, I also use 2" cowboys for a 2" PVC riser. I haven't failed an inspection but that doesn't mean I'm right in doing so.
 

jap

Senior Member
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Electrician
I once had 2-hole PVC straps on a 2" PVC riser for a 200A service. It was in direct sunlight and after 1 year most of the straps snapped off. Fortunately, the one at the top near the weather-head didn't. I went back and replaced them with 2-hole metal straps. I know it's not Code compliant but the CMP's making these rules are not out here in the field installing these services (maybe they did at one time and forgot what it's like). I don't know if they realize that we're not installing T-stat wire inside these conduits. :) For the record, I also use 2" cowboys for a 2" PVC riser. I haven't failed an inspection but that doesn't mean I'm right in doing so.
What's a 2" cowboy?

JAP>
 
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