Abstract: A lock for locking valve and electrical switch handles in the “off” position, which lock incorporates a radio transmitter for reporting status of the lock to a remote monitor. The lock has a cable which encircles the handle. The distal end of the cable is connected to the lock and is locked in place. A conductor of an alarm subcircuit passes through the cable, thereby detecting whether the cable has been cut. The monitor includes a radio receiver and a display for displaying status of the monitored lock. The invention optionally utilizes plural locks and plural monitors.