Wire Type for Burial?

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Hello,

I'm an engineer but this is beyond my practice. Here's the deal: building a new small shop about 70' away from the pole with meter and disconnect. Got the wire size figured out just fine, 4/0-4/0-4/0-2/0 AL. The wire has to be buried. Question is, what type of wire and should it (or not) go in a conduit?

Just not anything I've had to deal with before. Thanks.
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
I had temporarily closed this thread, in order to determine whether this was a DIY project. The OP convinced me, in a PM, that it is not, that it relates to his business. I am therefore reopening the thread. I offer my apologies to the OP for the delay and the inconvenience.
 

A/A Fuel GTX

Senior Member
Location
WI & AZ
Occupation
Electrician
Hello,

I'm an engineer but this is beyond my practice. Here's the deal: building a new small shop about 70' away from the pole with meter and disconnect. Got the wire size figured out just fine, 4/0-4/0-4/0-2/0 AL. The wire has to be buried. Question is, what type of wire and should it (or not) go in a conduit?

Just not anything I've had to deal with before. Thanks.

If you want to direct bury it, then URD is the way to go. I wouldn't do it that way unless the soil is sandy with no rocks to cause you grief later. If you run conduit, I'd go with 2 1/2" PVC and use XHHW conductors.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
If I may, use care :), "URD" (with only that rating) is actually a utility conductor and not recognized by the NEC. USE or UF would be a recognized conductor for direct burial (some 'URD' has added ratings).
For installation in a raceway, most any conductor with a "W" in the insulation. I agree the most common would probably be XHHW.
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
We do not direct bury unless the customer fully understands he is responsible for all rodent damage. Not even a tail light warranty. Usually the first repair would have paid for conduit, not counting the down time and PIA factor.

Rocks are not near the problem here.
 

A/A Fuel GTX

Senior Member
Location
WI & AZ
Occupation
Electrician
If I may, use care :), "URD" (with only that rating) is actually a utility conductor and not recognized by the NEC. USE or UF would be a recognized conductor for direct burial (some 'URD' has added ratings).
For installation in a raceway, most any conductor with a "W" in the insulation. I agree the most common would probably be XHHW.

Agreed........In my area, the URD most supply houses carry is the 8000 version which is RHH/RHW2 which is legal to install inside as well as outside a structure.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
We do not direct bury unless the customer fully understands he is responsible for all rodent damage. Not even a tail light warranty. Usually the first repair would have paid for conduit, not counting the down time and PIA factor.
From personal experience you should be just as concerned with rodent damage when using conduit unless you've sealed both ends.
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
We do not direct bury unlesin the customer fully understands he is responsible for all rodent damage. Not even a tail light warranty. Usually the first repair would have paid for conduit, not counting the down time and PIA factor.
From personal experience you should be just as concerned with rodent damage when using conduit unless you've sealed both ends.
We do duct seal, but once the box is on and covers closed, it is up to the owner to keep them on.

I learned early on just how much damage a mouse can do to a brand new pump panel in one night.:rant:
 

kwired

Electron manager
Location
NE Nebraska
We do not direct bury unless the customer fully understands he is responsible for all rodent damage. Not even a tail light warranty. Usually the first repair would have paid for conduit, not counting the down time and PIA factor.
From personal experience you should be just as concerned with rodent damage when using conduit unless you've sealed both ends.
That is the owners problem if they can't leave covers on. If rodents get into the underground raceway at least you can (usually) pull conductors out without digging everything up.
 
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