Conductor type for Service mast

skid330

New member
Location
Michigan
I am a little embarrassed to be asking this question, but my experience is in industrial settings, factories, power plants etc... I am a licensed journeyman electrician in the State of Michigan, but I don't really do much residential or construction type work, so here goes. I am helping a friend do a service upgrade, and I am not sure what type of conductor to use from the weather-head to the meter. It will be a 200 Amp overhead service, with a RMC mast. I believe I can use 4/0 XHHW in 2 in RMC. I believe XHHW is sunlight resistant, and rated for wet location, and high heat.

If I understand correctly I can't use SER cable. I am curious as to whether or not I can use URD wire like they sell at the Big Box stores, I don't believe I can, but I would just like to make sure.

Thanks
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
True URD cannot be used above ground but you can use 4/0 alum xhhw in 2" rmc. SER cable is 4 wire so you wouldn't use that but you could put ser inside the conduit but why would you do that.
 
I am a little embarrassed to be asking this question, but my experience is in industrial settings, factories, power plants etc... I am a licensed journeyman electrician in the State of Michigan, but I don't really do much residential or construction type work, so here goes. I am helping a friend do a service upgrade, and I am not sure what type of conductor to use from the weather-head to the meter. It will be a 200 Amp overhead service, with a RMC mast. I believe I can use 4/0 XHHW in 2 in RMC. I believe XHHW is sunlight resistant, and rated for wet location, and high heat.

If I understand correctly I can't use SER cable. I am curious as to whether or not I can use URD wire like they sell at the Big Box stores, I don't believe I can, but I would just like to make sure.

Thanks
In practice, you can probably use whatever conductor type you want. There are several situations where this might not be true, but I think theses are mostly academic most places due to multiple conductor ratings: 1) as mentioned, URD that is not an NEC wire type 2) THHN that is not also listed THWN 3) USE used above ground that is not also rated RHH. I think #3 is the only one I have seen but only a couple times. Perhaps these issues are common in some areas, but not here.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Since you have a 2" RMC just use XHHW or THWN and make sure that it's rated sunlight resistant. For some manufacturer's sunlight resistant conductors only come in black. You can use #4/0 aluminum or #2/0 copper.
 

kwired

Electron manager
Location
NE Nebraska
The URD sold at big box stores is probably dual marked as type USE as well as RHW. Sunlight resistant may be one thing to watch out for though it likely has that rating as well.

SER cable would be fine, but has one more conductor then you need, SEU cable would have the right number of conductors. Individual conductors likely cost less and would usually be easier to work with if pulling through a raceway anyhow.
 

iwire

Moderator
Staff member
Location
Massachusetts

kwired

Electron manager
Location
NE Nebraska
Don't think so, the big box stores are all about sales, not code compliance

Here is URD from HD, http://www.homedepot.com/p/Southwir...briar-URD-Wire-By-the-Foot-55418499/205001902 it is not sunlight resistant and no mention of dual ratings.
Do you trust that what is on the shelf is always going to be what is in that link?

HD is 100 miles from me so I don't get to see what they typically have for that type of thing.

I'm pretty sure Menards (midwest regional big box similar to HD) is closest big box to me and for items like this they seem to only stock stuff that is dual rated, though I almost never buy any wire/cable from them except NM cable, my supply house is better priced on almost everything else most of the time.
 

iwire

Moderator
Staff member
Location
Massachusetts
Do you trust that what is on the shelf is always going to be what is in that link?
Did I say that? I think the link even states product may vary.

But seriously, its URD, its not RHW.

I'm pretty sure Menards (midwest regional big box similar to HD) is closest big box to me and for items like this they seem to only stock stuff that is dual rated, though I almost never buy any wire/cable from them except NM cable, my supply house is better priced on almost everything else most of the time.
Well I have never seen a Menards so I won't comment on what they carry but it seems kind of funny you are so sure what they have when you say you don't buy it there. :D
 

kwired

Electron manager
Location
NE Nebraska
Did I say that? I think the link even states product may vary.

But seriously, its URD, its not RHW.



Well I have never seen a Menards so I won't comment on what they carry but it seems kind of funny you are so sure what they have when you say you don't buy it there. :D
I sometimes see what is on hand even if not purchasing it. The larger conductor/cables at the store nearest me just happen to be in the outside warehouse and I seldom go to that area. When I have looked at those cables they have been dual rated.

URD is not a NEC designation. Years ago it was primarily multiplexed USE cable.

My electric supply houses have both the USE only type and the dual rated stuff - not in all sizes but mostly dependent on what sells.

A lot of common sizes / number of conductors for on the farms is stocked in the USE only type, especially common sizes seen on irrigation services - customers often are purchasing the entire reel for one installation as service laterals to many of those are 1300-1500 feet long.

Sizes that are common for residential and light commercial services and feeders are stocked in dual rated conductor - especially ever since the State inspectors started looking for the right material about 15-20 years ago, that raised the demand to stock such things.
 

GoldDigger

Moderator
Staff member
Even if URD is similar to USE in its origin and characteristics, as long as it is only marked URD and not USE it still cannot be used for any Chapter 3 wiring purpose under the NEC.
 

kwired

Electron manager
Location
NE Nebraska
Even if URD is similar to USE in its origin and characteristics, as long as it is only marked URD and not USE it still cannot be used for any Chapter 3 wiring purpose under the NEC.
I have never seen any marked URD. The tag on the reel maybe but not on the conductors.
 
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