Aluminum GEC

[erickench]

Just recently I attended a seminar for my P.E. license continuing education. During the session the topic of aluminum grounding electrode conductors came up. The instructor stated that the 18" distance rule outlined in NEC 250.64(A)
does not apply to aluminum conductors that are insulated. Is this true?

 

[Dennis Alwon]

I disagree with your instructor. It is the termination part that is the issue not the insulated part.

 

[erickench]

I did'nt think so either. I look at the referenced NEC section and the first sentence say's that bare aluminum conductor cannot come in contact with earth or masonry. But the second sentence just say's aluminum conductor. The word bare is not written. Also, there are no written exceptions to this rule for this particular NEC section.

 

[charlie b]

But the second sentence just say's aluminum conductor.

I agree, and for that very reason.

 

[gndrod]

Just recently I attended a seminar for my P.E. license continuing education. During the session the topic of aluminum grounding electrode conductors came up. The instructor stated that the 18" distance rule outlined in NEC 250.64(A)
does not apply to aluminum conductors that are insulated. Is this true?

The instructor would have been correct had he included a disqualifying"Where used outside" for the 18" rule. An Aluminum grounding electrode conductor being 'inside' with less than 18" to the grounding conductor termination is permitted.