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Posted by N8N on November 6, 2009, 1:54 pm
> Existential Angst wrote:
> > 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 futu=
re
> > 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. =A0Other than t=
hat,
> > #12 would be fine with me.
> There's nothing "unmodern" about 14 for 15A circuits.
> I'd recommend sticking w/ same gauge as the original circuit for the
> reason mentioned.
> Remember to not bury connections in inaccessible places.
> > Next, =A0is there a rule of thumb for how many hot wires can share one =
neutral
> > of the same gauge? =A0If using different gauges, is there a "gauge rati=
o", ie,
> > some formula for cross sectional area between total hots and total neut=
rals?
> Don't follow this question. =A0Each hot needs its own return neutral.
> If you're talking about 3-wire ("Edison") circuits, if properly wired
> the return is in effect a neutral w/ a balancing currents from the two
> sides if both are loaded equally; hence only the same size conductor is
> required for a single-sided load.
> If that isn't it, I have no clue what you're thinking.
> --
If I'm following what he's asking correctly, I think he's trying to
pigtail some existing wires within a breaker panel to extend them to
their connection points. I also am guessing that this involves more
than one circuit, so he wants to connect several neutrals to a single
larger wire with a wire nut (or crimp cap, solder, whatever) and then
connect that larger wire to the bus, rather than pigtail each
individual neutral and connect them individually to the bus.
However, I have no input on whether this is even a valid
configuration; unless I were out of space on the bus bar I think I
would probably just pigtail each wire individually with a wire of the
same gauge - BUT I have no idea if what he's suggesting is OK per
code. (I suspect not; you wouldn't want a single point of failure to
affect multiple circuits. But that's just a guess based on thinking
it through, not actual knowledge of code.)
nate
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Posted by Existential Angst on November 6, 2009, 5:07 pm
> Existential Angst wrote:
> > 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.
> There's nothing "unmodern" about 14 for 15A circuits.
> I'd recommend sticking w/ same gauge as the original circuit for the
> reason mentioned.
> Remember to not bury connections in inaccessible places.
> > 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?
> Don't follow this question. Each hot needs its own return neutral.
> If you're talking about 3-wire ("Edison") circuits, if properly wired
> the return is in effect a neutral w/ a balancing currents from the two
> sides if both are loaded equally; hence only the same size conductor is
> required for a single-sided load.
> If that isn't it, I have no clue what you're thinking.
> --
If I'm following what he's asking correctly, I think he's trying to
pigtail some existing wires within a breaker panel to extend them to
their connection points. I also am guessing that this involves more
than one circuit, so he wants to connect several neutrals to a single
larger wire with a wire nut (or crimp cap, solder, whatever) and then
connect that larger wire to the bus, rather than pigtail each
individual neutral and connect them individually to the bus.
However, I have no input on whether this is even a valid
configuration; unless I were out of space on the bus bar I think I
would probably just pigtail each wire individually with a wire of the
same gauge - BUT I have no idea if what he's suggesting is OK per
code. (I suspect not; you wouldn't want a single point of failure to
affect multiple circuits. But that's just a guess based on thinking
it through, not actual knowledge of code.)
===============================================
Heh, you must be clairvoyant!! :)
Yeah, I figgered I'd keep it simple, rather than go into all that, but you
got it right.
NYC at one time had it in their code that you can't run a hot wire in a pipe
without a corresponding neutral wire in the same pipe.
Don't kinow if that's part of the NEC, or another NYC-ism.
The Q might be then, What constitutes "corresponding neutrals": one neutral
for one or two hots, or one big neutral for a bunch of hots?
No biggie just to extend each wire individually -- might even be simpler,
ultimately, esp.if future work will be done. Less to figger out.
--
EA
nate
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Posted by dpb on November 6, 2009, 11:38 pm
Existential Angst wrote:
...
> The Q might be then, What constitutes "corresponding neutrals": one
> neutral for one or two hots, or one big neutral for a bunch of hots?
>
Same as I gave you before except for 3-wire circuits--_every_ hot must
have its corresponding neutral, no exceptions.
--
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Posted by David Nebenzahl on November 7, 2009, 1:04 am
On 11/6/2009 8:38 PM dpb spake thus:
> Existential Angst wrote:
> ...
>> The Q might be then, What constitutes "corresponding neutrals": one
>> neutral for one or two hots, or one big neutral for a bunch of hots?
>
> Same as I gave you before except for 3-wire circuits--_every_ hot must
> have its corresponding neutral, no exceptions.
Yes, and from the OP's continued queries, it sounds more and more like
they don't really don't know much about wiring, which makes what they're
trying to do pretty doubtful.
To reiterate: the *only* circumstance where two hot wires can share a
neutral is in a so-called "Edison" circuit. The requirement is that the
hot wires must be on different phases--in other words, from different
buses in the distribution panel. That way, the sum of currents in the
one neutral can never exceed the wire's rating. The OP said some vague
things about "balancing loads": it's a whole lot more specific than that.
--
Who needs a junta or a dictatorship when you have a Congress
blowing Wall Street, using the media as a condom?
- harvested from Usenet
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Posted by Existential Angst on November 7, 2009, 2:08 am
> On 11/6/2009 8:38 PM dpb spake thus:
>> Existential Angst wrote:
>> ...
>>> The Q might be then, What constitutes "corresponding neutrals": one
>>> neutral for one or two hots, or one big neutral for a bunch of hots?
>> Same as I gave you before except for 3-wire circuits--_every_ hot must
>> have its corresponding neutral, no exceptions.
> Yes, and from the OP's continued queries, it sounds more and more like
> they don't really don't know much about wiring, which makes what they're
> trying to do pretty doubtful.
> To reiterate: the *only* circumstance where two hot wires can share a
> neutral is in a so-called "Edison" circuit. The requirement is that the
> hot wires must be on different phases--in other words, from different
> buses in the distribution panel. That way, the sum of currents in the one
> neutral can never exceed the wire's rating. The OP said some vague things
> about "balancing loads": it's a whole lot more specific than that.
There is nothing vague about "balancing loads".
What you may find vague, or perhaps are just unclear on yourself, is along
what part of the run can the load be balanced.
If you have 20 2-wire bx cables stopping, say, 10 feet short of a 20 circuit
panel, then, it seems to me, you can de facto *make* 10 edison circuits up
to the splice points, and therefore need only 10 neutrals going between the
panel and those 20 cables.
Thus, the edison circuit business is dependent on the actual *geometry of
the wiring*, ie, "partial length" edison circuits are possible.
Thus, your seemingly restrictive "only circumstance" for two hot wires
sharing one neutral is in fact a fairly non-limiting requirement in this
splicing circumstance, as ultimately, if a 20 circuit 240 V panel is filled,
you will *always* be able to make 10 edison circuits, for at least part of
the run.
AND, if you grok the above, then it follows that for that length of the
"edison run", you could, in principle, use one big neutral.
Not saying I will do this, just trying to eliminate some, well, vagaries.
Love your sig.
--
EA
> --
> Who needs a junta or a dictatorship when you have a Congress
> blowing Wall Street, using the media as a condom?
> - harvested from Usenet
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