The H600 is a current-sensitive switching device which monitors current (amperage) in the conductor passing through it. A change in amperage in the monitored conductor which crosses the switch threshold will cause the resistance of the status output to change state, similar to the action of a mechanical switch. In this model, the threshold is fixed at 150mA AC max (200mA AC for 50Hz operation). The status output is suitable for connection to building controllers, or other appropriate data acquisition equipment operating at up to 30 volts. The H600 requires no external power supply to generate its output.