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Wednesday, October 30, 2019
Question:
Re: CQD answer published Tuesday, October 22, 2019 - Conductor Size
Charlie,
Regarding: "The NEC does not require that all conductors in a circuit length be the same size. Sometimes larger conductors are used to deal with voltage drop concerns. Conductors must be protected as stated in 240.4. In your example the 12 AWG conductors are protected below their ampacity and the 14 AWG conductors are protected based on 240.4(D). That is allowed."
The problem I have with this wiring is what happens if the service is upgraded (new service panel)? The new electrician will probably use circuit breakers that match the wire size in the panel, not knowing there was a switch to #14 on the second floor (I've done it too many times to remember). A tag would be messy so I think the best 'solution' is to continue with #12 even though it's a pain to work with.
Dave
A
Answer:
Hey Dave thanks for your comment.
You have a point but also as you mention it is allowed to have different size conductors. If conductors are sized based on higher ambient temperatures or for more than three current carrying conductors as stated in 310.15(B)(2)(a) or 310.15(B)(3)(a) they appear to be protected below their ampacity when only looking at the connection to the overcurrent protective device but they might not be. Although not specifically required a tag or some other means, at the overcurrent protective device, could be helpful and not necessarily be difficult to do.