Undersized ground wire in NM cable

[mjf]

I am aware that it would be a code violation to extend a circuit that contains an undersized ground.

If the NM cable had 10 gauge grounded and ungrounded conductors with a 14 gauge ground wire, would it be a code violation to use 15amp OCP and extend the circuit with 14 gauge cable?

I don't know why questions like this occur to me, but they do:roll:

 

[ron]

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It seems resonable. How do you know the EGC is #14? Is it insulated with a mark?

 

[mjf]

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It seems resonable. How do you know the EGC is #14? Is it insulated with a mark?

Ah, hadn't thought about having to "prove" the ground wire is 14gauge. I think every time I've seen NM w/undersized ground the ground has been bare. I'd have to look on the sheathing to see if the ground wire size is listed. Like I said, sometimes I don't know where these questions come from.

 

[jumper]

It might be reasonable and safe, but I think it would be a violation of 250.122(B)

(B) Increased in Size. Where ungrounded conductors are
increased in size, equipment grounding conductors, where
installed, shall be increased in size proportionately according
to the circular mil area of the ungrounded conductors.

 

[mjf]

Great point

Great point

Excellent. As long as the wire is still being utilized "as found", it is compliant. If I changed it's use it would have to comply with 250.122(B).


Thanks. theoretical question answered. Love this site.