A safety switch and a circuit breaker respond to different electrical problems. A circuit breaker provides overcurrent protection; a safety switch, also called an RCD, detects an imbalance that can indicate current leaking outside the intended path. Neither function replaces the other.
If you are unsure which circuits have RCD protection, GMB’s safety switch installation and assessment service.
Circuit breakers protect against excessive current
An overload occurs when equipment draws more current than a circuit is designed to carry. A short circuit is another overcurrent condition. A correctly selected circuit breaker disconnects the circuit in response to these conditions, helping protect the wiring from damaging current.
It is not designed to detect every shock hazard. A dangerous current passing through a person may be too small to operate an ordinary circuit breaker. This is why the presence of breakers alone does not establish that a home has appropriate shock-risk protection.
Safety switches detect residual current
An RCD compares current flowing out and returning through the monitored conductors. An imbalance can cause it to disconnect. This provides additional protection against certain electric-shock risks, including some earth-leakage faults.
An RCD is not an assurance against every shock, and it does not make wet or damaged equipment safe to use. An ordinary RCD also does not replace overcurrent protection. Some devices, called RCBOs, combine both functions in one unit.
Why the distinction matters when power trips
A kitchen circuit could be overloaded by several appliances operating together. A different trip might involve moisture in an appliance, damaged insulation or a wiring fault. The symptoms can overlap, especially where combined devices are installed, so guessing the cause from the switch position is unreliable.
Do not repeatedly reset a device, hold it on or replace it with a higher-rated breaker to stop trips. The protective device may be responding correctly. Stop using affected equipment and have recurring trips investigated by a licensed electrician.
Questions for an existing-home assessment
Without opening the board, you can tell the electrician what you already know: which rooms lose power, when it happens and whether recent work or appliances changed. The electrician can identify the devices, assess coverage and test operation safely.
Ask whether circuits share an RCD, whether individual RCBOs are appropriate and whether any board or wiring work is needed to support the proposed protection. The answer depends on the actual installation rather than a universal upgrade package.
- Which circuits currently have residual-current protection?
- Is the recommendation for RCDs, breakers or combined RCBOs?
- Will existing faults need repair before protection is changed?
- What testing and circuit labelling will be provided?