I have a 30amp dryer circuit (4x10 gauge - 2hot, 1neutral, 1gnd) and a 20amp circuit (3x12 - hot, neutral, ground) coming into the same metal box. The 20 amp circuit continues on to another box where the 20amp outlet is and the 30amp outlet is in this box.
Do I need to splice all the grounds together in this box (and to the box)? Or, can I directly connect the 4x10 to dryer outlet (without any splices with the 20amp circuit), then splice the 12gauge ground together and to the box?
If I do need to splice them all together, do I need to use 10AWG to the metal box?