Trip siemens rccb catalogue pdf may be adjustable. Trip characteristics often fully adjustable including configurable trip thresholds and delays. Usually electronically controlled—some models are microprocessor controlled.
Often used for main power distribution in large industrial plant, where the breakers are arranged in draw-out enclosures for ease of maintenance. These can also be applied at up to 35,000 V. It trips the circuit when there is earth fault current.
RCD and trip the circuit within 30Miliseconed. 500 mA RCCB may be used where only fire protection is required. Limitation of RCCBStandard electromechanical RCCBs are designed to operate on normal supply waveforms and cannot be guaranteed to operate where none standard waveforms are generated by loads.
The most common is the half wave rectified waveform sometimes called pulsating dc generated by speed control devices, semi conductors, computers and even dimmers. Specially modified RCCBs are available which will operate on normal ac and pulsating dc.
RCDs don’t offer protection against current overloads: RCDs detect an imbalance in the live and neutral currents. A current overload, however large, cannot be detected. It is a frequent cause of problems with novices to replace an MCB in a fuse box with an RCD.