"Doug Miller" wrote in message
. net...
In article , Al Tsiemers
wrote:
I want to put in 2) 20A curcuits in my shop area. I would like to have
them
both go to a string of twin duplex boxes, with the left-hand duplex
recepticle in all boxes on one curcuit, and the right-hand on the other
circuit.
My calculations show a 32 c.i. box is required for 12ga. wire.
Questions:
1) I assume the grounds for both circuits can/should be tied together,
correct? They are uninsulated, so I can't see how that could be avoided.

There's no particular reason why they need to be tied together, and if you
use
non-metallic boxes, it's avoidable.

2) If the first box in line gets two GFCI outlets (one for each circuit),
does that change the calculation for box size? Does the yoke count of 2
for
each device change because of the depth of a GFCI receptacle?

I don't see anything in the Code that indicates that it does.


When I read your reply and the original post, I starting thinking (always a
dangerous thing to do.)

Would it be "legal" to just run a single 120/240 circuit and at the first J
box put in a pair of GFCI's with the other circuits fed by the load side of
that first pair? The advantage is there would be two less current carrying
wires in each box (except the last), only one pair of GFCI's would be
needed. The neutral and ground would have to be pigtailed of course.

Along that line, it is "legal" to have a 240 volt outlet share a 120/240
circuit with the 120 volt duplex outlets? I understand that the 15/20 amp
duplex outlets are treated differently that the 120/240 or 240 outlets
although it doesn't make much sense from a safety view point.