Derating conductors

[lwcarter]

in a commercial building that i am presently wiring, i cam accross a question no one can answer.
i have a 3/4" pipe running from one switgh location to another switch location. all the switches are 3-ways.
the question i have is: do i have to count all 3 wires for each 3-way, or only two of these wires?

my thought is only 2 because there are only 2 current carrying condugtors per switch at any one time. this is an on going debate within our office..any insight would be great

lee

 

[Nick]

Re: Derating conductors

You only need to count one of the two travelers as only one caries current at a time.

 

[hornetd]

Re: Derating conductors

I agree with Nick. Just as the grounded conductor of a complete multiwire branch circuit, the equipment grounding conductor, or an additional isolated grounding conductor would not count the idle traveler does not count for derating. It does, of course, count for conductor fill.
--
Tom