Is there a specific electrical code that states how many wires can be
attached per screw when wiring outlet receptacles?
I've always heard that when wiring receptacles, one shouldn't attach more
than one wire to each screw. I haven't been able to locate anything about
that in the 2008 National Electrical Code. It may be in there, but so far,
I haven't been able to find it.
Part of why I am curious is that I notice that typical outlet receptacles
have two silver screws, two gold screws, and only one green grounding screw.
And that started me wondering, "Why aren't there two green grounding
screws?" For outlets that are in the middle of a circuit, there are
typically six wires in the outlet box -- two black, two white, and two
grounds. So, wouldn't it be easier if the receptacle had 6 screws? -- two
for the two black wires, two for the two white wires, and two for the two
Is it possible that the code allows two ground wires to be connected to the
one green grounding screw, but does not permit two wires per screw for the
white and black wires?