RCBOs?
What are they?
Residual Circuit Breakers with Overcurrent Protection (RCBOs) are circuit breakers which combine the functionality of an MCB and an RCD.
What is an MCB?
MCB which stands for Miniature Circuit Breakers are electromechanical devices that switches off the circuit automatically if an abnormality is detected. The MCB easily senses the overcurrent caused by the short circuit. The miniature circuit has a very straightforward working principle. Additionally, it has two contacts; one fixed and the other movable.
If the current increases, the movable contacts are disconnected from the fixed contacts, making the circuit open and disconnects them from the main supply.
What is an RCD?
RCD which stands for Residual Current Device is an electrical wiring device that disconnects the circuit as soon as it detects a current leak to the earth wire. It also protects against electric electrocution or shock caused by direct contact.
So what is an RCBO?
A Residual Current Breaker with Over-Current (RCBO) combines the functionality of an MCB and RCD. When there is a current leakage, the RCBO trips the entire circuit. Consequently, internal magnetic/thermal circuit breaker components can trip the electronic device when the circuit is overloaded.
Effective 1st Jan 2019 when the updated electrical wiring standard, AS/NZS 3000:2018 became mandatory - any work done on a circuit must be equipped with RCD protection. For our situation, this is particular relevant for Sanden Eco heat pump hot water systems and Daikin heating/cooling installations which require a power input.
Want to know if your MCB (Circuit) is already RCD protected or not?
Some clues for determining this:
- Do you see a GREEN STICKER below or above the breaker? If GREEN, then YES most likely. If RED or no colour, then Most likely NO.
- To confirm if it is an RCBO - Look for a TEST button on the Circuit Breaker
See below a photo example with circles indicating the TEST button on the Circuit Breaker.
