Installation of smoke alarms and heat alarms

Smoke alarms and heat alarms should be permanently wired to either – (a) a regularly used lighting circuit; or (b) a circuit which – (i) is separately fused at the distribution board; (ii) serves only smoke alarms and heat alarms; and (iii) where a residual current device is used – is not connected to a residual current device which is also used by any other circuit. Smoke alarms and heat alarms may operate at a low voltage via a mains transformer. The cable for the power supply to, and interconnection of, the smoke alarms need not have special fire-survival properties.