Trident Instruments has released the LSI-55 load status indicator.
With a supply voltage of 10V to 300V AC or DC, the LSI-55 will illuminate green, indicating that power is available to operate a load. In one example, the load is a simple lamp, but a motor or heater or any type of electrical load that draw less than 30A can be used.
With the LSI-55 illuminating green, the switch can be placed in the on position to turn the lamp on. If all is OK with the lamp and the wiring to the lamp, the LSI-55 will illuminate red, indicating that the load is active and that the lamp is drawing current (greater than 1A). If the LSI remains green, then the wire to the lamp is defective or, the more probable cause, the lamp is burned out.