Standards BS4737: Insulated cables, PVC insulated for intruder alarm systems NEC 725/800: CM / CL2, BS4737: Insulated ... cables, PVC insulated for intruder alarm systemsNEC 725/800: CM / CL2,1. Power cable, PVC ... use in conduit and for fixed, protected installation of Wiring Burglar Alarm, Public Address Systems, Intercoms, Telephone Stations, Speakers, Instrumentation, ...