residual current device RCD820 advanced RCD type A load side mounted rated resid. current 0.03...30A at 50/60Hz adjustable tv 0...10000ms 4-pole In=160A Ue=100-690V accessory for: 3VA2 Residual current ammeters for 3VA molded-case circuit breakers. Residual current devices can be used to prevent or reduce hazardous residual currents that could cause injury to personnel and livestock, and damage to property. These are available as accessory components for the 3VA series. All residual current protection devices detect both purely sinusoidal AC residual currents as well as pulsating DC residual currents (type A). Key features of these accessory components: 1. Available as type A (pulse current-sensitive). 2. Easy mechanical installation of the residual current ammeters direct at the switch. This allows a very compact design.