XHHW-2 Direct Burial Ground

[thien]

I have been told by a cable manufacturer that XHHW-2 can be used in a direct burial application as a ground, while others have told me that it is not allowed. I have not been able to find any information where this is allowed unless the cable is dual rated with a direct burial marking per the UL white book. Does anyone know of a special exception for grounds?

 

[Dennis Alwon]

If you are talking about a connection to a ground rod or a concrete encased electrode then it really doesn't matter as the jacket is not necessary anyway.

 

[thien]

I should have mentioned that the Cable is aluminum and cannot be bare.

 

[iwire]

I should have mentioned that the Cable is aluminum and cannot be bare.

Than no it cannot be used.

If it was copper I would say it could be used.

 

[Dennis Alwon]

I should have mentioned that the Cable is aluminum and cannot be bare.

Read art 250


Just kidding - look at 250.64(A)

 

[augie47]

A world of confusion can often be avoided by using a more descriptive term than "ground".
Distinguishing between "grounded" and "grounding" and "grounding electrode" conductors can, at times, provide widely different answers.

 

[GoldDigger]

Read art 250


Just kidding - look at 250.64(A)

What that does not tell us, though, is whether the insulation which will just be protecting the wire from corrosion and will not be exposed to an applied voltage still needs to be listed for wet conditions or for direct burial. My answer is to assume that it must, or risk both damage and problems from the inspector.

 

[thien]

Sorry for not being more specific earlier. I am assuming that XHHW-2 is still not allowed if used as an equipment grounding conductor even if I meet the conditions of 250-122(B).

 

[iwire]

Sorry for not being more specific earlier. I am assuming that XHHW-2 is still not allowed if used as an equipment grounding conductor even if I meet the conditions of 250-122(B).

In my opinion, because XHHW-2 is not listed as a direct burial insulation we cannot consider the insulation as the preventing the aluminum conductor from being in direct contact with the earth.

250.120(B) Aluminum and Copper-Clad Aluminum Conductors.
Equipment grounding conductors of bare or insulated aluminum
or copper-clad aluminum shall be permitted. Bare
conductors shall not come in direct contact with masonry or
the earth or where subject to corrosive conditions. Aluminum
or copper-clad aluminum conductors shall not be terminated
within 450 mm (18 in.) of the earth.

 

[Smart $]

XHHW-2 along with all other Table 310.104(A) conductor types do not have a direct burial application provision.

Listed or identified as suitable for direct burial is completely separate distinction.

Should there be a single-conductor aluminum XHHW-2 cable out there marked for direct burial, it can be used for such.

 

[kwired]

XHHW-2 along with all other Table 310.104(A) conductor types do not have a direct burial application provision.

Listed or identified as suitable for direct burial is completely separate distinction.

Should there be a single-conductor aluminum XHHW-2 cable out there marked for direct burial, it can be used for such.

I agree. All direct burial cables I have seen are usually RHW series types or just marked USE and nothing else - which can not enter a building.