I am wiring a new shop and using deep 2 gang boxes to put 120 duplex outlets and 240 volt outlets around the walls. I am running them as seperate circuits both with 12 gauge wire for 20 amp circuits. So in most boxes I have 4 cables, two in and two out. My question is can all the ground (bare) wires be tied together with pigtails for the two outlets or do the ground wires for each circuit need to be kept seperate. I know they all end up on the same bar in the main box, but wasn't sure if there was an issue with them all tied together at the outlet box from 2 different circuits.
A second question is about voltage dividers. When I told the city inspector what I was going to do, he indicated that I would have to put a voltage divider in the box. I found some dividers at home depot, but no boxes that they actually fit. The local wholesale electric outlet said they didn't carry them. The only reference I am able to find requiring their use is if low voltage (data/phone) wires are combined in the same box with line voltage. Is anyone aware of a requirement to use them with dual voltages in a box with 120 and 240?