The most essential tool for diagnosing faults in any decoder system is a sensitive current clamp meter. This is often referred to as a Leakage Clamp Meter. With this, it is easy to find main cable leakage to earth, shorts, opens and faulty decoders without cutting up the main cable. For testing decoder cable, Clamp Meter should be used with faultfinding Transformer, this will facilitate the measurement and location of earth leakage from the decoder cable. Quickly clamp over one of the 2Wire communication wires without having to un-do existing wire splices, saving both time and money.  Measures full-scale current 40mA to 100 Amps.  AC volts to 500v, Resistance 400 ohms.