The ABB 2CSJ203001R0001 is an RD3P-48 electronic residual current relay from the RD3 series. It provides residual current protection and earth-fault monitoring, and works with the whole ABB S200 miniature circuit breaker range and with Tmax moulded-case breakers up to T5, which is why it is normally specified for industrial boards rather than for final domestic circuits. It is a Type A device, so it detects sinusoidal AC and pulsating DC residual currents. Sensitivity and tripping delay are both set on the device, which is what lets one part number cover a range of installations and lets discrimination be arranged with the devices downstream. Supply voltage is 12 … 48 V AC/DC. The P version adds an LED bar showing the measured leakage current as a proportion of the trip setting, a pre-alarm threshold at 60 % and a frequency filter, and it supports automatic reset, selected with a dip switch: with auto-reset on, the output contacts return to standby by themselves once the fault clears, which suits unattended and remote installations where a manual reset would mean a site visit. Supplied by cBallast on quote-to-invoice terms; lead time and freight are quoted per RFQ against the destination Incoterm.