NFPA 731 Section 4.6.3.12(2) requires raceways to be sized properly in accordance with the NEC^®. Raceways, conduits and tubing are not always used with security system wiring but if they are, the raceway conduit or tubing must be sized according to the NEC^®.

In the NEC^®, there are two main locations (near the back of the book) used when determining the maximum number of conductors in a conduit or tubing:

• NEC Annex C is used for determining the maximum number of conductors permitted in conduit or tubing, when all conductors in the conduit are of the same size and insulation type.
• NEC Chapter 9 is used for combinations of conductors of different sizes or insulation types installed in the same conduit or tubing.

There are many tables in NEC Annex C, each of which is for a different raceway type. For example, Table C.1 in Annex C provides the maximum number of conductors or fixture wires permitted in electrical metallic tubing (EMT) while Table C.3 provides the maximum number of conductors or fixture wires permitted in flexible metal conduit (FMC). Refer to the image of NEC^® Annex C Table C.1 to answer the question below.

Below is a sample of NFPA 731. For the complete section, see the actual NFPA 731 text at NFPA.ORG. Once there, click on the free access link to the latest edition of NFPA 731.

4.6.3 Wiring.

4.6.3.12 At raceway connections to junction boxes and open ends of raceways, the following shall apply:

(1) Conductors shall be protected from abrasion.

(2) Raceway shall be sized and installed in accordance with NFPA 70.