Eaton xEffect FRCdM Residual Current Circuit Breaker (RCCB) — Type Bfq, 4-Pole, 40 A, 300 mA, Selective (167909)

The Eaton 167909 is a residual current circuit breaker (RCCB) from the Moeller series xEffect FRCdM range. It disconnects the circuit when the current flowing out does not match the current returning — the signature of a fault to earth, whether through failed insulation or through a person. It provides no overcurrent protection of its own and is installed together with the circuit's MCB or fuse. This device is 4-pole, rated 40 A, with a rated residual current of 300 mA. Type Bfq is Eaton's type B variant with a tripping curve adapted to reliably sense residual currents up to 50 kHz. It is the frequency-converter type, for installations whose normal operating leakage is itself high-frequency and would otherwise cause nuisance tripping or, worse, mask a real fault. Bfq and B+ are not interchangeable: B+ is chosen for fire protection, Bfq for drive-heavy installations. It is the S (selective) version, which trips with a deliberate time delay so that an instantaneous RCD downstream clears the fault first and only the affected circuit is lost. A selective device belongs at the head of a board, not on a final circuit. At 300 mA it is intended for protection against earth-fault fire and for equipment protection, not for protection against direct contact — that requires a 30 mA device. Supplied by cBallast on quote-to-invoice terms; lead time and freight are quoted per RFQ against the destination Incoterm.