Mike holt practice quiz Q.

[hectorsevilla23]

NEC Exam practice questions
Practice quiz 8, question 12.

What is the minimum size copper supply side bonding jumper for a service raceway containing 4/0 THHN aluminum conductors?

A) 6 awg aluminum
B) 4 awg aluminum
C) 4 awg copper
D) 3 awg copper


Using A. 250.102 (c) 1
T 250.66

Why would is the answer C? 4awg- when it looks more like it should be 2/0 ?


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[david luchini]

NEC Exam practice questions
Practice quiz 8, question 12.

What is the minimum size copper supply side bonding jumper for a service raceway containing 4/0 THHN aluminum conductors?

A) 6 awg aluminum
B) 4 awg aluminum
C) 4 awg copper
D) 3 awg copper


Using A. 250.102 (c) 1
T 250.66

Why would is the answer C? 4awg- when it looks more like it should be 2/0 ?


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Per T250.66, #4/0 Aluminum conductors would call for a #4 Copper GEC, or in this case bonding jumper.

 

[Dennis Alwon]

So I assume you know that 4 copper is what the Table states so you are looking for why it is #4 and not 2/0--- why do you think it should be 2/0. We are not talking about a grounded conductor but the size of the bonding jumper. The grounded conductor can be as small as the bonding jumper if the load calculates to be that small but it cannot be smaller than #4