Mixed use of copper/aluminum conductors

[chenry]

I have just been approached by an engineer to install copper equipment grounds for all the aluminum feeders on the job site. These grounds are are installed in the same race way. Is this per NEC?

 

[beanland]

Al & Cu

Al & Cu

Totally. All the correct terminations and ampacity rules must be applied to the specific conductors.

 

[brian john]

So aluminum is fine for power conductors but in a fault condition he wants copper on 1/2 the circuit.

 

[beanland]

Bare?

Bare?

In some cases, the copper ground wire can be bare. 250.118. Saves a little $$.

 

[wasasparky]

So aluminum is fine for power conductors but in a fault condition he wants copper on 1/2 the circuit.

I would want copper for the smaller conductor sizes...just my preferece...

 

[brian john]

I would want copper for the smaller conductor sizes...just my preferece...

Mpreference also...BUT I utilize copper throughout, not just the EGC.

 

[haskindm]

Sounds like this "engineer" knows just enough to be dangerous!
What possible reason could he give (that makes sense) for installing copper grounds with aluminum power conductors? If aluminum is not suitable for the ground conductor (in his opinion), how could it possibly be suitable for a conductor that actually carries current! I would LOVE to hear his explanation for this nonsense!

 

[sparkyjim]

Did several large "assisted-living" centers, and everyone of them were spec'd to have aluminum feeders and and copper grounds throughout. Never good get a real answer. Just assumed that some engineer had heard something at a party and decided it must be true.