3 -way switch box location requires a neutral ?

[wwhitney]

Can you quote the exact words, and how you come tothe e understanding you have?

As kwired noted, the requirement in 300.3(B) has the exclusion "unless otherwise permitted in accordance with 300.3(B)(1)through(B)(4)."

300.3(B)(3) says in its entirety:

(3) Nonferrous Wiring Methods. Conductors in wiring methods with a nonmetallic or other nonmagnetic sheath, where run in different raceways, auxiliary gutters, cable trays, trenches, cables, or cords, shall comply with the provisions of 300.20(B). Conductors in single-conductor Type MI cable with a nonmagnetic sheath shall comply with the provisions of 332.31. Conductors of single-conductor Type MC cable with a nonmagnetic sheath shall comply with the provisions of 330.31, 330.116, and 300.20(B).

What are these 3 sentences saying? Each one is just reiterating a requirement that exists elsewhere in the code. Conductors of a circuit using multiple entries to a box always have to comply with 300.20(B). Single conductor Type MI always needs to comply with 332.31. Single conductor Type MC cable always has to comply with the provisions listed.

So why are these sentences repeated here in the NEC? They are not adding any requirements. They are not informational notes, just referring you to potentially applicable sections. Rather, they are being reiterated here, because in this context, located in 300.3(B)(3), they are implicit exceptions to the general rule in 300.3(B). It would be clearer if 300.3(B)(3) started off "the provisions of 300.3(B) shall not apply in the following circumstances:" But given the context and location, that meaning is implicitly clear.

Cheers, Wayne

 

[kwired]

As kwired noted, the requirement in 300.3(B) has the exclusion "unless otherwise permitted in accordance with 300.3(B)(1)through(B)(4)."

300.3(B)(3) says in its entirety:



What are these 3 sentences saying? Each one is just reiterating a requirement that exists elsewhere in the code. Conductors of a circuit using multiple entries to a box always have to comply with 300.20(B). Single conductor Type MI always needs to comply with 332.31. Single conductor Type MC cable always has to comply with the provisions listed.

So why are these sentences repeated here in the NEC? They are not adding any requirements. They are not informational notes, just referring you to potentially applicable sections. Rather, they are being reiterated here, because in this context, located in 300.3(B)(3), they are implicit exceptions to the general rule in 300.3(B). It would be clearer if 300.3(B)(3) started off "the provisions of 300.3(B) shall not apply in the following circumstances:" But given the context and location, that meaning is implicitly clear.

Cheers, Wayne

And if you aren't entering a ferrous enclosure those other sections don't really matter, which is often the case with NM cable and most device/outlet boxes anyway. And if you do have say two 14-2 for the "same circuit" into a metal box, if you happen to have both in the same connector (when applicable) you still meet the requirements that apply at the box.