Elec Box Capacity/3-way Switch Questions - Electrical - DIY Chatroom Home Improvement Forum

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Old 02-28-2011, 09:30 AM   #1
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Elec box capacity/3-way switch questions

Hi All, Two questions in one. I have as part of 3 way switch configuration a round 4" box on the wall for my lights, regular sconces, I'm scratching my head cause:
1. the box says it should have only a max of 8 # 12 wires and this one has three 12/2 connected in the box feeding two bulbs in the light fixture. So isn't this to many for this size box?

2. think I figured this one out. didn't have my second cup of coffee! So just the box capacity question needs answering. Do i count the grounds??




Last edited by walt1122; 02-28-2011 at 09:46 AM.
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Old 02-28-2011, 09:54 AM   #2
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(U.S. rules)
All the ground wires together count as one point.
All the cable clamps or fingers, if any protrude into the box, count as one point.
The switch itself counts two points.
Pigtails (short wires wholly within the box) and wire nuts count zero points
One point is 2-1/4 cubic inches for 12 gauge wires.
A capacity of eight #12 wires means at least 18 c.i.


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Last edited by AllanJ; 02-28-2011 at 09:59 AM.
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Old 02-28-2011, 11:06 AM   #3
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Thanks AllanJ

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