NFPA 731 Section 4.6.3 is all about proper installation of security system wiring methods including circuit separation, terminations, circuit identification, protection from abrasion and cable strain relief.

NFPA 731 Section 4.6.3.4 requires at least a 2-inch separation between low voltage security system wiring and power or lighting circuits unless the cable is listed for closer proximity or installed in a listed raceway. If not properly separated, electrical noise can cause interference in the low voltage security system wiring from adjacent power circuits. These undesirable electrical signals are caused by the hum of the 60 HZ alternating current in the power circuits. Interference or noise in the security system circuits can create incorrect readings and false signals.

Additional circuit separation requirements are found in NEC^® 725.48 for Class 1 circuits and NEC^® 725.136 and 725.139 for Class 2 and 3 circuits.

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.

4.6.3.1 The installation of all wiring, cable, and equipment shall be performed in accordance with NFPA 70, Article 725 or Article 800, where applicable.

4.6.3.2 Optical fiber cables shall be protected against mechanical injury in accordance with NFPA 70, Article 770.

4.6.3.3 A conductor shall be spliced or joined with a mechanical splicing device listed for this purpose.

4.6.3.4 Unless specifically allowed by the manufacturer's wiring specifications, low-voltage premises security system wiring shall be spaced at least 50.8 mm (2 in.) from conductors of any light and power circuits, unless one of the circuits is in raceway listed for the purpose.