Patent ID: 7482940

Claim:
An alarm for detecting radiation and/or pollutants having: a housing; an alarm circuit including a detector capable of detecting said radiation and/or pollutants; a first electrical connection directly connected to one of an external live power cable of a main circuit and a light side of a switch for a lighting circuit for supplying external power to said alarm circuit; a second electrical connection connectable to said light side of said switch for the lighting circuit, wherein the first electrical connection supplies external power to the alarm circuit independent of the connection to the second electrical connection; a circuit connecting said first electrical connection to said alarm circuit for supplying said external power to said alarm circuit; a first switch mounted on said alarm housing and actuable by a user to generate a respective pulse for each actuation thereby; and a control circuit responsive to receipt of a preselected number of pulses, from either the second electrical connection or the first switch, over a preselected time period to apply a preset control signal to said alarm circuit; wherein said alarm circuit is responsive to said preset control signal to reset or test said alarm in dependence on said preset control signal.