Existential Angst wrote:
"bud--" wrote in message

Since you are posting fairly often, do you have a copy of the NEC?
Are you reasonably proficient at reading it?

Very helpful info, thank you.
I have a 1996 NEC, and I *could* be proficient at reading it if the
essentials weren't drowned in thousands of other words. But yeah, the
tables in App. B and C do get to the point.

It seems that many others have trouble reading the NEC, as there is a whole
cottage industry of workbooks and guides in how to read, understand, and use
the NEC. wow....

The NEC has been revised 4 times since your 1996 copy. Revisions can
change often used sections. And numbering in some articles has been
changed, so references may not match your copy.

The NEC is not laid out to be easy to learn (it is a reference).
Information on installing an outlet, for instance, is in buried in
several articles. Good reason for the cottage industries.


I just came home with 100 ft of 3/4 greenfield, two 500 ft rolls of #14
wire -- which, btw, just jumped $5 a roll in the past 3 days. Man, I hate
gving money to HD -- who nevertheless charge in some cases quite a bit less
than electrical supply houses for wire -- but a hair more for greenfield.

What I wrote was based on THHN insulation. That is probably what you
bought, but not necessarily. The wire is probably marked THHN/THWN. If
not, the number of wires in a conduit is likely different.

But I managed to read the wrong column for ampacity. Particularly
annoying because the value I read was not what I remembered. What I
wrote is revised below.

310.16 gives the allowable "ampacity" for the wire. Assuming it is #14
with *THHN* insulation the ampacity is 25A (but cannot be used at over 15A).

310.15(B)(2)(a) requires the ampacity to be reduced if there are more
than 3 wires in a conduit. If you have 7-9 "current-carrying" wires, the
ampacity is reduced to 70%. For #14 *THHN* the ampacity is then 17.5A
and you can still use it on a 15A circuit. You can not have more than 9
"current-carrying" #14 *THHN* wires in a conduit and connect them to a
15A breaker.

310.15(B)(4) says that the neutral of a 3 wire "Edison" circuit does not
count as one of the "current-carrying" conductors.

310.15(B)(5) says that ground wires do not count as "current-carrying"
conductors.

You can run 4 "Edison" circuits, 12 - #14 *THHN* wires (8
"current-carrying" conductors) in a single conduit. Add a #14 ground wire.

Appendix C.3 says the 13 - #14 conductors can be run in a 1/2"
Greenfield. It is the maximum number and you would have to pull the wire
carefully. With 3/4" Greenfield you shouldn't have a problem

For 2 wire circuits (if you do not combine them to be "Edison"
circuits), you can run 4 - #14 *THHN* circuits in the same conduit - 8
"current-carrying" wires plus ground = 9 wires.

--
bud--