I'm the GC on the renovation of a 1780 post&beam farmhouse.

Currently have some disagreement on the job site. Some feel that because communication wiring is run in the unblocked wall from basement to 2nd floor, riser rated cable is required. Others disagree and state the NEC indicates type CM is always sufficient for single family residential dwellings.

Can somebody point me one way or the other.

As about 50% of the place is already wired in CM, we are hoping this meets the NEC, but will rewire if required.

Thanks

George

I do not believe you need riser rated cables in residences, see 1999 NEC 800-53-b exception #2, which basically allows CM or CMX cables in one and two family dwellings. The newer NEC will probably read the same.

NEC 2002 made this positive language
800.53(B) Riser. Cables installed in risers shall comply with 800.53(B)(1), (B)(2), or (B)(3).
...
(3) One- and Two-Family Dwellings. Type CM and CMX cable shall be permitted in one- and two-family dwellings.

NEC2005 moved this to 800.154 but the language didn't change

Many thanks. It is quite clear that type CM is sufficient in single family dwellings regardless of whether the space is considered a "riser" or not.

Elsewhere someone had suggested:
725.61(B)(3), since it allows CL2 and CL3 in 1-2 family dwellings and the cable hierarchy allows substitution of type CM where CL2/3 is allowed.

George