DIYbanter - View Single Post - Can you use white for one leg of 240V circuit?

dpb

On 5/2/2011 9:11 AM, wrote:
On Mon, 2 May 2011 04:45:43 -0700 (PDT), jamesgangnc
wrote:

Actually 10/2 with a three prong plug was acceptable for dyers for a
long time.

Not really. The code called that 3d wire a "neutral" that was also
being used as a ground and the neutral was always required to be an
insulated conductor. I agree a lot of inspectors ignored this
violation but that did not make it right.

No, it was _NOT_ a Code violation until NEC was changed to make it such.

I don't know which version did make the change; the latest reference at
hand is based on NEC 1984; 3-wire (as in two leads and a ground) was
compliant at the time. NEC Sec 220-18 at the time required minimum
10-ga and grounding the case to the neutral was acceptable.

And, at that time, NEC 338-3(b) allowed that for ranges, ovens, cooktops
and clothes dryers the cable may have bare neutral that served as both
the neutral and the equipment grounding connector. The one restriction
on that was that it had to be a single, direct run from the equipment;
no branches allowed. This was/is virtually always the case in single
residential installations.

I'd venture it was mid-90s or thereabouts the reqm't for 4-conductors
became codified; as said I don't have a listing of changes and when were
made and I'm not going to go look for it. I am certain (as I just
looked it up) that it was within Code thru 1984 as outlined above.

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