On 7/3/2014 6:37 AM, trader_4 wrote:
On Wednesday, July 2, 2014 6:06:27 PM UTC-4, dpb wrote:

....big snip...

If I'd been on the NFPA Code Committee when this came up I'd have voted
"no" simply on the cost/material basis of there being no demonstrable
real problem being solved that justified the added expense. "Parsimony"
is a virtue in engineering, too...
....

Do you have any reason to believe it's part of the NEC?

A, as you say, it makes no sense at all from any physics

B, wells here are put in with 240V, 2 hots + ground all the time
and they pass electrical inspection.

I was mixing both topics here and switched back once too quickly,
apparently...

No, I do _NOT_ think there's likely anything in NEC that justified the
4-wire cable in the well-hole; I have yet to discover from whence came
the supposed edict referred to by the well service guys...

What I was speaking of in the "voting against" comment is the new
section that requires the 4-wire for the grounding of the oven/dryer
branch circuit. There as you I do see there is at least an issue; I
just don't agree that the disease is worth the cost of the cure given
the history (or more correctly, the lack thereof) indicating it is a
safety issue of any magnitude at all.

I obviously wasn't in the room but I'd have had to seen an impressive
litany of cases where it had been the root cause of a problem and if
that were to have been demonstrated then I don't see how it could have
been justified to leave the exception standing. Making the change was,
imo, just bureaucracy doing what it does in this case. Most of the time
NFPA does a pretty good job but I think they misstepped on this one.

--