I'm upgrading wiring in an older home which originally had ungrounded
two-wire fabric-sheathed cable. I replaced it with 12/2 with grounding
wire in a few circuits.

The existing handy boxes (is that the right word for outlet boxes?) are
not as big as the ones currently being sold.

For a middle of the run receptacle, I'm looking at 4 wires + ground +
grounding wire nut (the one with the pass through if you've seen them)
and clamps in one of those boxes which is 12 cu in or less, and I can
barely close up the outlet cover.

I'm wondering, is it required to change the outlet boxes to the bigger
14 cu in (or bigger) boxes when I upgrade the wiring? That would be
much more work than I had originally anticipated.

Thanks.

--
Himanshu

Greetings,

The NEC requires that you allocate 2.25 in^3 for each 12 awg wire
entering the box. No matter how many grounds enter the box you only
count 1 ground. Your receptacle counts as 2 wires. Add it all
together and I come out with

2.25 hot going to the receptacle
2.25 neutral going to the receptacle
2.25 hot going from the receptacle
2.25 neutral going from the receptacle
2.25 grounds
5.5 receptacle
========================================
15.75 in^3
2.25 cable clamps inside box
========================================
18.00 in ^3

If you do upgrade the boxes 14 in^3 would be a violation of the NEC.
If you don't upgrade the boxes your inspector will likely allow them to
be grandfathered in but they won't have enough room to hold the wires
without cramming. If you do decide to cram try to avoid pigtails and
wire nuts. Make each wire exactly 6" long. In some tight boxes I have
done away with the wire nut for the ground to save room. Allow one
ground wire to loop 3/4ths of the way around the ground screw attached
to the metal box and then continue on. Allow the other ground wire to
wrap around the ground screw of the self-grounding receptacle and
continue on. Next twist the ground wires together tightly for about
1" but do not put a wire nut on. I only bring this up for the
exceptionally tight box.

Hope this helps,
William

I believe you could also just put in a GFI outlet or circuit breaker
to give you protection from the ungrounded wiring. That's what happened
in my house. I had some circuits on ungrounded 12 and 14 gauge Romex
and it was too much of a pain to re-run it, so when I had my service
panel changed to 200 Amps, we put in GFI circuit breakers. It is
allowed under code.

I believe you're off on your receptacle calc. It should be 4.5 shouldn't
it? Either way, it's a bit irrelevant since his current boxes are not near
the 17 in needed.

" wrote in message
oups.com...
Greetings,

The NEC requires that you allocate 2.25 in^3 for each 12 awg wire
entering the box. No matter how many grounds enter the box you only
count 1 ground. Your receptacle counts as 2 wires. Add it all
together and I come out with

2.25 hot going to the receptacle
2.25 neutral going to the receptacle
2.25 hot going from the receptacle
2.25 neutral going from the receptacle
2.25 grounds
5.5 receptacle
========================================
15.75 in^3
2.25 cable clamps inside box
========================================
18.00 in ^3

If you do upgrade the boxes 14 in^3 would be a violation of the NEC.
If you don't upgrade the boxes your inspector will likely allow them to
be grandfathered in but they won't have enough room to hold the wires
without cramming. If you do decide to cram try to avoid pigtails and
wire nuts. Make each wire exactly 6" long. In some tight boxes I have
done away with the wire nut for the ground to save room. Allow one
ground wire to loop 3/4ths of the way around the ground screw attached
to the metal box and then continue on. Allow the other ground wire to
wrap around the ground screw of the self-grounding receptacle and
continue on. Next twist the ground wires together tightly for about
1" but do not put a wire nut on. I only bring this up for the
exceptionally tight box.

Hope this helps,
William

I believe you're off on your receptacle calc. It should be 4.5 shouldn't
it? Either way, it's a bit irrelevant since his current boxes are not near
the 17 in needed.

Greetings,

Important: My original total, 18 in^3, is correct. 17 in^3 is too
small.
Yes, the 5.5 is a typo and should be 4.5.

Sorry for any confusion,
William

Himanshu wrote:
I'm upgrading wiring in an older home which originally had ungrounded
two-wire fabric-sheathed cable. I replaced it with 12/2 with grounding
wire in a few circuits.
snip
I'm wondering, is it required to change the outlet boxes to the bigger
14 cu in (or bigger) boxes when I upgrade the wiring? That would be
much more work than I had originally anticipated.

Thank you all for your suggestions.

The local inspector said that for the end-of-the-run, I could keep the
older box, but for middle-of-the-run, I would have to install a bigger
box during the upgrade.

--
Himanshu