Quadplex vs triplex URD w/ ground

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JoeNorm

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For most services around here its triplex URD with a separate ground, all pulled in conduit.

Our suppliers do not carry quadplex. When asked about it one told me "it's just not that popular here" and another said there is something "weird" about the quadplex. I assume he was talking about the listing.

I know this topic has been covered, I looked through older threads. But I am still unsure if there is a problem with quadplex to serve in a residential setting?

Why would nobody carry it. It is readily available for order online.
 
JoeNorm said:
Replace "services" with "feeders"
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Then you need the EGC,
I know of no problem adding one when needed. I think it just a supply-demand issue...most the installs are for "services" so the 3 wire is commonly stocked and a 4th wire added as needed.
(sidenote: "URD" as a sole listing is not a NEC recogniozed insulated conductor...most will have an added rating as USE or RHW or both)
 
None of my suppliers carry full-size quad. They have triplex and MH feeder with a half size neutral.

I needed some quad a couple weeks ago in a pinch and bought another 4/0 AL and wrapped it in the triplex. 0/10 will never do that again, they can just wait next time for me to order wire.

Edit to add…. It was in conduit , and they didn’t have enough 4/0 to cut me three separate conductors. Just had enough for one and the triplex .


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There is a difference between "4 wire URD" and MHF. For 4 wire URD, the code words are colleges and it's available with both a full size and a reduced neutral. For example "wake Forest" is three 4/0 and one 2/0 and "earlham" is 4 - 4/0. These cables are typically USE-2 and RHH-2, but that can vary by the manufacturer. MHF is essentially the same as the URD with the reduced neutral, but usually has a green conductor.
 
electrofelon said:
There is a difference between "4 wire URD" and MHF. For 4 wire URD, the code words are colleges and it's available with both a full size and a reduced neutral. For example "wake Forest" is three 4/0 and one 2/0 and "earlham" is 4 - 4/0. These cables are typically USE-2 and RHH-2, but that can vary by the manufacturer. MHF is essentially the same as the URD with the reduced neutral, but usually has a green conductor.
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You can get MH feeder with a full size neutral. My supplier just doesn’t stock it.

www.southwire.com

Mobile Home Feeder Cable with Alumaflex® Brand Conductors | Southwire

Get high-quality Mobile Home Feeder Cable with Alumaflex® Brand Conductors from Southwire. Perfect for direct burial & permanent wiring.
www.southwire.com www.southwire.com


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brantmacga said:
You can get MH feeder with a full size neutral. My supplier just doesn’t stock it.

www.southwire.com

Mobile Home Feeder Cable with Alumaflex® Brand Conductors | Southwire

Get high-quality Mobile Home Feeder Cable with Alumaflex® Brand Conductors from Southwire. Perfect for direct burial & permanent wiring.
www.southwire.com www.southwire.com


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Yeah you are correct, I looked too quickly, I'm looking at a southwire spec sheet and they have it both with a reduced neutral and without. The EGC is also smaller on the one with reduced neutral.
 
James L said:
For me, I'd much rather use 4 separate wires
4/0 - 4/0 - 2/0 - 1/0

Sometimes it's 4/0 - 4/0 - 1/0 - 2
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The Plexed stuff does have some advantages. It's a bit easier to setup and deal with only one reel, but the main thing is you can pull in conductors that would have a high jamming probability and basically not be feasible with single conductors. For example we did a 700 ft pull of 250-250-3/0 urd in 2-in PVC. Also a 500-500-1/0 about the same length in two and a half PVC. I would not have tried those with single conductors.
 
I have a EGC question that has become an interesting item. URD as a feeder run to separate buildings, local AHJ says NEC does not require an EGC because a grounding electrode system is installed at each building. I am not familiar with that exception. Have I been spending a lot of extra time effort and money for nothing? Can anyone give where to go in the NEC for this one?
 
kevin.luce@matsuk12.us said:
local AHJ says NEC does not require an EGC because a grounding electrode system is installed at each building.
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That's a somewhat old allowance that went away in the 2008 NEC maybe? Or perhaps a bit earlier.

So for an existing feeder without EGC, if there are no other metallic paths between the buildings, you can still use it. But any feeder you install today has to have an EGC.

See 250.32(B)(1) and its Exception #1.

Cheers, Wayne
 
kevin.luce@matsuk12.us said:
I have a EGC question that has become an interesting item. URD as a feeder run to separate buildings, local AHJ says NEC does not require an EGC because a grounding electrode system is installed at each building.
Click to expand...
NOT correct. Earth does not carry enough current to activate an OCPD when a ground fault occurs.
 
kevin.luce@matsuk12.us said:
I have a EGC question that has become an interesting item. URD as a feeder run to separate buildings, local AHJ says NEC does not require an EGC because a grounding electrode system is installed at each building. I am not familiar with that exception. Have I been spending a lot of extra time effort and money for nothing? Can anyone give where to go in the NEC for this one?
Click to expand...
Sounds to me like another person who totally doesnt understand grounding. Note you ALWAYS need a low impedance path back to the source. A grounding electrode is NEVER a low impedance path back to the source. The exception Wayne was referring to allowed the neutral conductor to be bonded like a service and to serve as the EGC/low impedance path back to the source. A GES was and is still required.
 
electrofelon said:
Sounds to me like another person who totally doesnt understand grounding. Note you ALWAYS need a low impedance path back to the source. A grounding electrode is NEVER a low impedance path back to the source. The exception Wayne was referring to allowed the neutral conductor to be bonded like a service and to serve as the EGC/low impedance path back to the source.
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I guess I'm giving whoever might have said that the benefit of the doubt, and they they intended to provide a low impedance fault clearing path by rebonding the neutral and EGC at the supplied building, using the feeder neutral as the fault clearing path. Which was routinely allowed in the past, so it might just be info that's 15-20 years out of date.

Cheers, Wayne
 
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