"Existential Angst" wrote in message
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"RBM" wrote in message
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"Existential Angst" wrote in message
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Awl --

A two-part Q:

Due to some remodeling, I'm forced to splice/lengthen some old bx cable
that has #14 wire in it, and re-connect to the fuse box.
Should I splice the #14 with #14, or splice with #12?

The reason I would continue with #14 wire is just to remind me and
future people that Hey, this old wire is a little lighter than modern
#12, and to not take liberties with 20 or 30 amp fuses or breakers.
Other than that, #12 would be fine with me.

Next, is there a rule of thumb for how many hot wires can share one
neutral of the same gauge? If using different gauges, is there a "gauge
ratio", ie, some formula for cross sectional area between total hots and
total neutrals?

tia.
--
EA
keep the conductors the same size as is existing

14ga is and has always been fine for 15 amp circuits

12ga is and has always been fine for 20 amp circuits (even in NYC)

NYC, prior to 2005 has always used the NEC as the basis for electric
code. Only certain areas did they require more stringent rules.

Well, iiuc, ALL municipalities use the NEC as a "basis".

Regarding NYC, I read the opposite here on this ng in a recent thread:
NYC relaxed its onerous electric code to substantially the NEC AFTER 2001
or 2003. Before that, it was quite stringent.

I know for a fact (well, at least if my bosses were correct!) that in the
1980's, you could *not* put 20A breakers on #12 wire -- at least not
before inspection.

As another example, in those days, you were allowed eight #12 conductors
in 1" EMT -- in fact, it was 3, 5, and 8 for 1/2, 3/4, and 1" EMT,
respectively.

Nowadays, for 1" emt, NYC allows pretty much what the NEC allows -- pert
near close to 20 wires in 1" emt! What a diff.

This may also reflect more modern wire insulation material.
--
EA


Your neutral can be shared by as many hot legs as your service has,
typically 2


Every three years a new set of rules comes out in the NEC. It's entirely
possible that the "conductors in conduit" changes are reflective of that.
I've never seen #10 used for 20 amp circuits in NYC. If the conductors were
aluminum, not copper, that would be the case, although I'm not sure if NYC
ever allowed small conductor aluminum wire.