URD vs Conduit

[NTxAg]

Is there any advantage to using conduit.

I am looking to run 2-2-2 AL URD from my panel to my subpanel in my shop, the run is 100' and I will be installing a grounding rod next to the shop. I dug the trench 18" deep, there is no code where I live. Is there any advantage to using conduit? If the cable is rated for burial then it seems like a waste, but my knowledge on this subject is pretty low. I know I have to install conduit on the vertical runs from the panel into the ground and from the ground up to the subpanel.

 

[Movover]

The General consensus is the price of conduit is so little its worth the extra to put it in. That way if there is a problem you can pull out the old without the digging. Also URD I believe is not to be used indoors you would need a outdoor termination to SER or use Mobile Home Feeder "MHF" in full conduit

 

[NTxAg]

The General consensus is the price of conduit is so little its worth the extra to put it in. That way if there is a problem you can pull out the old without the digging. Also URD I believe is not to be used indoors you would need a outdoor termination to SER or use Mobile Home Feeder "MHF" in full conduit

So I would need a 1' length of SER just to go from the URD through the wall and into the panel?

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[brewchief]

In almost every case now you will need to run a ground wire as well, 2-2-2-4 MHF would be a better choice as long as it carries the proper rating to be used indoors, you will need conduit at the ends of either urd or mhf.
Running conduit the whole way gives added protection and should allow you to replace the wire in the future if it became damaged.

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[NTxAg]

In almost every case now you will need to run a ground wire as well, 2-2-2-4 MHF would be a better choice as long as it carries the proper rating to be used indoors, you will need conduit at the ends of either urd or mhf.
Running conduit the whole way gives added protection and should allow you to replace the wire in the future if it became damaged.

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Okay, if I am grounding the sub panel at the shop via grounding rod why the additional grounding wire? I don't doubt you just looking for clarification.

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[Movover]

Sub panels are required to be bonded back to the main panel, at the sub panel you need to remove your neutral bonding screw and have a separate neutral/ground bars also your 2 ground rods 8' apart bonded back to the sub panel

 

[brewchief]

Basically the ground rods are for lightning protection and the ground wire is for clearing faults, there are a couple guys around here who will give a better explanation but if it's after the first point of disconnect it needs 4 wires.

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[NTxAg]

Gracias.

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[NTxAg]

The URD is free from a family member, can I just pull bare 4awg wire with it for my fourth strand?

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[Spudland_Dave]

The General consensus is the price of conduit is so little its worth the extra to put it in. That way if there is a problem you can pull out the old without the digging. Also URD I believe is not to be used indoors you would need a outdoor termination to SER or use Mobile Home Feeder "MHF" in full conduit

Depends on who you talk to really..
I would say that all the sparky's I talked to said the same thing...Conduit is a waste of money unless you go real big (driving up the $$) cause pulling 125' of 2-2-2-4 thru "normal sized" conduit sounds easier then it really is. And quite honestly if you properly install direct burial, it should be good for life to begin with. Some people make it sound like electric wire is a consumable that wears out.

I just put 30' of 3" conduit under my driveway so if I ever need to replace my URD, I don't need to cut my asphalt.

 

[NTxAg]

Depends on who you talk to really..
I would say that all the sparky's I talked to said the same thing...Conduit is a waste of money unless you go real big (driving up the $$) cause pulling 125' of 2-2-2-4 thru "normal sized" conduit sounds easier then it really is. And quite honestly if you properly install direct burial, it should be good for life to begin with. Some people make it sound like electric wire is a consumable that wears out.

I just put 30' of 3" conduit under my driveway so if I ever need to replace my URD, I don't need to cut my asphalt.

I am going to use conduit, decent chance that concrete gets poured over this at some point.

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[Charles (in GA)]

So I would need a 1' length of SER just to go from the URD through the wall and into the panel?

That is correct. URD insulation is not properly rated for fire resistance and the NEC simply does not address it at all. It cannot be used inside a building. It is a underground distribution cable, intended to be run from say, transformer underground to meter, or outside disconnect underground to outside shutoff. I know you said codes do not apply to you in this location, but it is always best to adhere to the minimum standard, in this case, the code, ESPECIALLY with things that cannot be easily changed later.

Charles

 

[Charles (in GA)]

If the soil is rocky, then conduit is a good idea. If the soil is sandy or clay with few rocks, then direct burial is OK. Rocks will get up against a wire and rub thru the insulation, allowing water inside and then corrosion sets in and the wire burns thru. I had this happen on the underground feed from the transformer to my meter. POCO actually found three bad spots, two burned thru, the third wasn't simply because the others gave way first.

Charles

 

[NTxAg]

Thanks Charles, that is why I was asking. I realize that there is usually some things you can fudge on and some things you absolutely can't. As I mentioned the URD is available for free so it is hard to pass up even if it requires another step or two.

 

[walrus]

Thanks Charles, that is why I was asking. I realize that there is usually some things you can fudge on and some things you absolutely can't. As I mentioned the URD is available for free so it is hard to pass up even if it requires another step or two.

Dig the trench deeper, bed of sand, urd, sand to cover. 6 inches under and 6 inches over should do it. I wouldnt bury conduit without bedding it either.

 

[914wilhelm]

My neighbor wished he had conduit. It was either the gophers or the rocks. He lost his neutral followed by his appliances.

 

[NTxAg]

As I previously mentioned, the URD was free, can I just pull a 4awg with it for my ground?

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[brewchief]

Yes you can add a wire for your ground, if you have the urd post up the markings as some carries the ratings needed to go indoors.

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[NTxAg]

2 AWG AL TYPE USE-2 600V SUN-RES XLPE UL COREAL 15/12/29 NUETRAL H.O.

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[Two Sheds]

Per table 300.5, in conduit it can be 18 inches minimum depth, direct bury needs to be 24 inches minimum depth. So you will need to dig a deeper trench if you don't use conduit.

 

[NTxAg]

Talked to the electrician that is going to do the hook-up and we are good. I pulled a 4th wire with the URD through conduit. I went with 2" after the mention of gophers and how it would be easier to fix later once concrete is over it.

Thanks everyone for the help, no way I could have tackled all the stuff I have done lately without the help for the members of this site.

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