Turns out I'm one circuit short in my shop subpanel. I need another
240V outlet, but have no free slots, and can't solve my dilemma with
half-heights (it's only an 8 slot sub). I also cannot fish to the
location I want (without massive renovation) from another 240V
receptacle (they're currently all dedicated circuits). My plan was to
pull the sub and install a bigger sub to run the new circuit (it's
easy to fish from the existing sub to the receptacle location).
However, that involves a fair amount of work as well, but I'll do that
if that's what the NEC spells out.
So the question is, in lieu of the bigger subpanel, can I simply put
both circuits (existing + new) into the circuit breaker or can I make
up a pigtail in the subpanel box so only one wire goes into the
breaker? I'm guessing (been too long to remember) the former is a
no-no (multiple wires under single screw) and have no clue about the
latter.
Any of you NEC experts have the handy answer?
[email protected] (Tom Bergman) wrote in
news:[email protected]:
> ...
>
> So the question is, in lieu of the bigger subpanel, can I simply put
> both circuits (existing + new) into the circuit breaker or can I make
> up a pigtail in the subpanel box so only one wire goes into the
> breaker? I'm guessing (been too long to remember) the former is a
> no-no (multiple wires under single screw) and have no clue about the
> latter.
>
> Any of you NEC experts have the handy answer?
>
I'm not an expert but I've done a little research in this area...Multiple
wires to a breaker would be allowed if the breaker is listed for it. The
breaker should say something on the label about 2 wires if it is. Some
SquareD QO series breakers allow it for a certain range of copper wire,
for example.
Splices in a panel aren't forbidden by the NEC. It comes down to whether
or not there's room in the panel to do it safely. If you have to get an
inspection it's probably up to the inspector.
Another possibility would be to break the line to one of your existing
receptacles and add a couple of junction boxes to allow an extension to
your new location.
Pedantic nitpick...you mention adding another "circuit". Neither of
these wiring methods will give you another circuit, just another
receptacle on the same circuit as the existing receptacle. You won't
have the additional capacity a new circuit would provide.
Doug
"Wade Lippman" <[email protected]> wrote in
news:[email protected]:
> I agreed with you on the splices and the multiple wires, but you lost
> me on the pedantic nitpick. A circuit is everything between the
> breakers and the outlets. Two circuits can share one breaker. Now if
> he were to splice the two circuits together, rather than double wire
> the breakers, I might agree with you.
I think I see what you're saying from a schematic view but I don't believe
that's the common definition of a circuit as used in AC wiring around a
house. A circuit is usually everything controlled by a single breaker.
Typically when someone speaks of adding a new circuit they want additional
capacity for running more stuff at the same time. I only brought it up
because none of the wiring methods we were discussing accomplished that.
Doug
"Wade Lippman" <[email protected]> wrote in message
news:[email protected]...
>
> I agreed with you on the splices and the multiple wires, but you
lost me on
> the pedantic nitpick. A circuit is everything between the breakers
and the
> outlets. Two circuits can share one breaker. Now if he were to
splice the
> two circuits together, rather than double wire the breakers, I might
agree
> with you.
It's still only one circuit. It's just semantics of routing.
One breaker - one circuit.
John Sellers
"Doug" <[email protected]> wrote in message
news:[email protected]...
> [email protected] (Tom Bergman) wrote in
> news:[email protected]:
>
> > ...
> >
> > So the question is, in lieu of the bigger subpanel, can I simply put
> > both circuits (existing + new) into the circuit breaker or can I make
> > up a pigtail in the subpanel box so only one wire goes into the
> > breaker? I'm guessing (been too long to remember) the former is a
> > no-no (multiple wires under single screw) and have no clue about the
> > latter.
> >
> > Any of you NEC experts have the handy answer?
> >
>
> I'm not an expert but I've done a little research in this area...Multiple
> wires to a breaker would be allowed if the breaker is listed for it. The
> breaker should say something on the label about 2 wires if it is. Some
> SquareD QO series breakers allow it for a certain range of copper wire,
> for example.
>
> Splices in a panel aren't forbidden by the NEC. It comes down to whether
> or not there's room in the panel to do it safely. If you have to get an
> inspection it's probably up to the inspector.
>
> Another possibility would be to break the line to one of your existing
> receptacles and add a couple of junction boxes to allow an extension to
> your new location.
>
> Pedantic nitpick...you mention adding another "circuit". Neither of
> these wiring methods will give you another circuit, just another
> receptacle on the same circuit as the existing receptacle. You won't
> have the additional capacity a new circuit would provide.
>
I agreed with you on the splices and the multiple wires, but you lost me on
the pedantic nitpick. A circuit is everything between the breakers and the
outlets. Two circuits can share one breaker. Now if he were to splice the
two circuits together, rather than double wire the breakers, I might agree
with you.
You can not use the power panel as a splice/junction box. You can put a
gutter or small 4x box on the side/top/etc and splice in there.
Erik
"Tom Bergman" <[email protected]> wrote in message
news:[email protected]...
> Turns out I'm one circuit short in my shop subpanel. I need another
> 240V outlet, but have no free slots, and can't solve my dilemma with
> half-heights (it's only an 8 slot sub). I also cannot fish to the
> location I want (without massive renovation) from another 240V
> receptacle (they're currently all dedicated circuits). My plan was to
> pull the sub and install a bigger sub to run the new circuit (it's
> easy to fish from the existing sub to the receptacle location).
> However, that involves a fair amount of work as well, but I'll do that
> if that's what the NEC spells out.
>
> So the question is, in lieu of the bigger subpanel, can I simply put
> both circuits (existing + new) into the circuit breaker or can I make
> up a pigtail in the subpanel box so only one wire goes into the
> breaker? I'm guessing (been too long to remember) the former is a
> no-no (multiple wires under single screw) and have no clue about the
> latter.
>
> Any of you NEC experts have the handy answer?