bare aluminum EGC in pvc conduit.

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apbart

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Gentlemen,

Can anybody tell me the code reference, that states that you cannot use a bare aluminum stranded equipment grounding conductor installed in a pvc conduit, in which the conduit is installed underground? The EGC is used for a feeder ground from a main panel to a sub panel in a detached garage, the wire is #4 bare stranded aluminum grounding conductor, with 3 - #2 aluminum insulated feeder conductors.

Any information will be of help,
Thanks, apbart.
 
The use of an aluminum EGC, bare or insulated, is permitted by 250.122(B) so long as it does not come in direct contact with masonry or earth, or where subject to corrosive conditions.

Bare installed in PVC would not be in direct contact with earth. However, subject to interpretation, underground in PVC could be considered a corrosive condition. Such interpretation could vary from AHJ to AHJ, and location to location.

PS: Welcome to the forum :)
 
I have seen overhead triplex installed in underground raceway before - when we pulled it out the bare aluminum was pretty much gone throughout most of the run except for the steel messenger strand. Homeowner installed it between his house and garage.

I would not advise using bare aluminum underground.

I locate and repair a lot of underground wiring - aluminum is always disintegrated if there was any damage to insulation. Copper will continue to work for a long time. Seen many improper splices in copper that worked for many years. Seen many improper splices in aluminum that only lasted a few weeks.
 
There is a very good reason that USE cable has an insulated ground. Think about it. Not sure I have ever seen bare alumin. except in SE cable or overhead triplex type cables.
 
Dennis Alwon said:
There is a very good reason that USE cable has an insulated ground. Think about it. Not sure I have ever seen bare alumin. except in SE cable or overhead triplex type cables.
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IIRC I have seen USE cable with a bare conductor (but I won't testify to my memory being 100% accurate :D)
 
Smart $ said:
IIRC I have seen USE cable with a bare conductor (but I won't testify to my memory being 100% accurate :D)
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And it was aluminum? Maybe a long time ago but aluminum does not like the corrosive conditions of the soil and I would be surprised if it exists today.

We know there is a reason for this rule as well as one for the equip. grounding conductor in 250.120(B)

250.64 Grounding Electrode Conductor Installation.
Grounding electrode conductors at the service, at each building or structure where supplied by a feeder(s) or branch circuit(s), or at a separately derived system shall be installed as specified in 250.64(A) through (F).
(A) Aluminum or Copper-Clad Aluminum Conductors. Bare aluminum or copper-clad aluminum grounding conductors shall not be used where in direct contact with masonry or the earth or where subject to corrosive conditions. Where used outside, aluminum or copper-clad aluminum grounding conductors shall not be terminated within 450 mm (18 in.) of the earth.
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