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Subject - Travelers
David Hyatt In a conduit,travelers for a 3 way switch, should only be counted as one current carrying conductor, since the current is only on one traveler at a time?
Ryan_J I agree. I would only count them as one CCC, but I would count them both for conduit fill.
cs409 All current carrying wires count, used or not! but i never count as 2,,,,, its interesting subject, and leads to a lot of ifs and what ifs..........
lctrc789 OK guys does the neutral of a single phase count as a conductor?? NO it doesn't, only a 3 phase wye 4 wire neutral counts as a conductor when derating. Article 310 15b 4(a)&(b).
David Hyatt Pat, I agree thats what I am suggesting in my other post. (Neutral)
cs409 i agree also.........am just stating more or less the nec.
Pierre Belarge

I am very curious as to where in 310.15(B)(2) it excludes (maybe by way of exception), one of the conductors used as a traveler, from the ampacity adjustment calculations. I do not see where it is excluded from this requirement.

Remember - 310.15(B)(4) specifically requires that the neutral of 2 phase conductors installed from a 3 phase 'system' is required to be counted in the ampacity adjustment calculation. An example: A 3 phase system panel supplying a 2 pole 30 amp dryer with the neutral.

Pierre
Ryan_J
quote:
Originally posted by lctrc789

OK guys does the neutral of a single phase count as a conductor?? NO it doesn't, only a 3 phase wye 4 wire neutral counts as a conductor when derating. Article 310 15b 4(a)&(b).



Ray, are you telling me that a nuetral of a two wire, single phase circuit doesn't carry current?
David Hyatt I think it does but for the purpose of derating it is not required to be counted.
Ryan_J You don't think (a) requires it?
iwire
quote:
Originally posted by David Hyatt

In a conduit,travelers for a 3 way switch, should only be counted as one current carrying conductor, since the current is only on one traveler at a time?


That is a good question, I agree with Ryan, I do not think we need an exception for this.

How about this one, you have piped in a lot of hi hats they are all on one circuit but 5 different switches, you brought the feed to the switch from overhead and then brought up the 5 switch legs through the same pipe.

Six current carrying conductors?

I think so.

I think we have a few different conversations going on here.

There is a major difference between a neutral that has current flowing through it and what the code calls a current carrying conductor.

A simple two wire circuit from any supply system, both wires carry current and the NEC requires the Neutral conductor of this circuit to be called a current carrying conductor.

A circuit consisting of 2 hots from different phases and a neutral from a single phase source. In this circuit the neutral will most likely carry current but the NEC does not count this as a current carrying conductor.

A circuit consisting of 3 hots different phases and a neutral from a three phase source. In this circuit the neutral will most likely carry current but the NEC does not count this as a current carrying conductor.

Now when we have a circuit that has 2 hots different phases and a neutral from a three phase source. In this circuit the neutral will carry current and the NEC requires it to be counted as a current carrying conductor.

Also on a 4-wire, 3-phase wye circuit where the major portion of the load consists of nonlinear loads, harmonic currents are present in the neutral conductor; the neutral shall therefore be considered a current-carrying conductor.
David Hyatt Ryan (a) says same circuit, so maybe it may have to be counted. The word (same) I didn't see before. But it should be more specific like b&c.
Ryan_J I agree with you David, it should be more clear.