The MICRO-4 is a compact earth fault relay with adjustable sensitivity from 30 to 300 mA and a 1 second tripping delay, running from a 230 V AC supply and providing a potential-free normally-open alarm contact. An earth fault relay measures the residual current — the difference between the current flowing out to a load and the current returning from it, which is only non-zero when some of it is escaping to earth — and signals rather than breaking the circuit itself, so it can be applied to circuits far larger than a self-contained RCD could switch and set for sensitivity independently of the device it drives. This is the version supplied WITH the indicator panel, which gives a visible earth fault indication at the board or door. The only difference between this item and the MICRO-4 listed without a panel is the panel itself — the relay, its 30 to 300 mA adjustable range and its 1 second delay are identical. Manufactured in Spain and supplied under the Function brand. Supplied by cBallast on quote-to-invoice terms; lead time and freight are quoted per RFQ against the destination Incoterm.