On 11/11/2012 7:13 PM, Nate Nagel wrote:

Aside: Why don't spec grade "back wire" devices allow two ground wires
to be inserted under a single screw like the hots and neutrals?


My guess is that if you replace the receptacle while the circuit is live
you break the ground downstream. The same is true of the neutral. You
can have a "hot" neutral or ground downstream. A hot neutral is not
likely to be a problem (except for the person changing the receptacle).
A hot ground, even for a short time, can be fatal.

For multiwire (Edison) circuits you are not allowed to connect the
neutral through the receptacle. It has to be spliced separately, and a
single neutral wire connects to the receptacle. If replace the
receptacle hot, and break the neutral, one downstream leg-to-neutral can
wind up at 240V and the other 0V.