"Wayne Whitney" wrote in message
...
On 2010-09-26, Doug Miller wrote:

I'm technically not allowed to do this because that would be too many
wires/devices. 20 cu in is the deepest single gang box available. And
with two sets of 14-2 wires spliced, I used up 17 cu in of nominal space
(2x4x2 + 1).

Where does that "+ 1" come from?

That's his allowance for the EGCs, but it's not quite right. It
should be (2 * 4 + 1) * 2, or 18 in^3.

Here's what your calculation *should* look like:
4 14ga cables @ 2 conductors each = 8 conductors
add 1 for one or more equipment groundi ng conductors
add 1 for each cable clamp in use (presumably at least 2)

You only need to count clamps that extend into the box, so the
integral clamps on a plastic box do not need to be counted. Thus I
assume he's using a plastic box.

Plus, since we are talking about a one-gang box, for a plastic
one-gang and NM cable, you don't need to clamp the wire to the box, as
long as you secure the wire close enough to the box (I forget the
requirement). Single-gang plastic boxes typically don't have cable
clamps at all.

Cheers, Wayne

Also, there are 22cu. in. plastic single gang boxes, or he could use a deep
plastic 1900 box with single gang reducing cover. Then he can go hog wild.