For safety of anyone working on these outlets in the future, I would suggest
using a tiebar breaker (like for 240 volt circuits) for the circuits in
these boxes and placing a note in the breaker panel that these outlets are
on two circuits.

The tiebar will force them to turn off both circuits at the same time.

This would keep someone from turning off the circuit to say the left outlet
and still having live power on the right side and zapping themselves...



"Al Tsiemers" wrote in message
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.
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?