Reduced size ground wire in NM?

[mlnk]

Is the ground wire in NM smaller than the black and white wire? I know that years ago it was, but is that the case now? I am asking because this is mentioned in the FAQ in this NEC forum.

 

[Dennis Alwon]

Is the ground wire in NM smaller than the black and white wire? I know that years ago it was, but is that the case now? I am asking because this is mentioned in the FAQ in this NEC forum.

The egc is the same size as the conductors in sizes 14-10. Once you get higher then that the sizes change to match, hopefully with 250.122. This can be a problem when upsizing for VD as the EGC may not change depending on the wire sizes.

 

[kbsparky]

Type NM-D wire which is sold in Canada still has reduced grounding conductors in it.

A #12 romex cable uses a #14 ground.

 

[don_resqcapt19]

MN in sizes 14, 12, and 10 has had a full sized EGC (in the NEC world) since the late 60's or very early 70's.

 

[kbsparky]

MN in sizes 14, 12, and 10 has had a full sized EGC (in the NEC world) since the late 60's or very early 70's.

It was the 1971 edition of the NEC that started this requirement. Manufacturers followed with upgrades in their NM cables during that year.