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#### enochian

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197 Posts
Discussion Starter · ·
Three 14/2 NMB
One 14/3 NMB
2 devices

#### CodeMatters

· Very Stable Genius
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I wouldn't bother with box fill calculations. Just use a basic plastic 2Gang
with ~37CI capacity. Plenty of room for wires plus GFI/dimmer/occ sensor/
whatever. Done.

#### enochian

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197 Posts
Discussion Starter · ·
I would but I'm adding a cable to an old box.

#### CodeMatters

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I see. Well I'd do the calc for you but the CEC does them differently than the NEC,
so I don't think that'd be much good to you.

#### Colbyt

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5,712 Posts
I'm surely not the expert on this but I will answer the question. Assuming ground wires on all cables:

3
3 ×
--------------------------
9 =

4 +
--------------------------
13 =

2 +
--------------------------
15 =

And I missed the CEC part of the equation.

#### Jim Port

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18,339 Posts
3x2=6, 1 x3=3' 2x2=4

6+3+4+1 ground = 14 conductors

14x2=28, no allowance for a clamp.

Colbyt

#### rjniles

· A "Handy Husband"
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15,069 Posts
3 14/2 6
1 14/3 3
1 ground 1
2 devices 4
total 14 x 2 cu in = 28 cu in

If the box has internal clamps add 2 more cu in, total 30

to add another cable (assuming #14), add 2 cu in for each current carrying conductor. No addition for ground.

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