SO cord

[Twoskinsoneman]

I know cords count the ground in their designation (ie SOOW cord 14/3 has 3 conductor) and cables don't (ie NM 14/2 has 3 conductors). Whose standard is this? Does the NEC describe them this way?
Thanks

 

[kkwong]

I've wondered about the same thing. I think with NM we automatically include the ground in the count and with SO we don't for some reason. Perhaps it is a NEMA thing.

 

[augie47]

cord vs NM

cord vs NM

I'm not sure I agree with the original statement.
NM does not necessarily include the "ground".. there's 10/2 NM and 10/2 with ground NM.
In the case of cords, normally all the conductors are the same size, so a 6/3 cord would have 3 #6 conductors, where as a 3 conductor 6/2 wg would have 2 #6 condcutrs and a #10 ground.
Therefore, to me, cords are identified by the actual number of conductors of one size, whereas, NM is identified as having a ground (or not) sized according to the "phase" conductor/s

 

[kkwong]

true, Augie. I forgot that you can get ungrounded NM...guess my (young) age is showing and, isn't the ground in NM one size smaller (generally) then in that case, we would count the number of conducters at that particular size.