Isolator (isolating switch)
Also called: isolating switch, isolation switch, AC isolator, switched spur
An isolator is a manual switch whose only job is to fully disconnect a circuit or appliance from the electrical supply, so a technician can work on it with no live power. You'll see one as the switched spur beside a water heater, the rotary switch by an AC outdoor unit, or the cooker isolator in a kitchen. The key distinction: an isolator isolates, it doesn't protect — unlike an MCB or RCBO it won't trip on a fault; it's simply a safe, deliberate off-switch. That's why a proper AC or water-heater service always starts at the isolator, and why an AC unit that trips or has electrical faults should be isolated before anyone opens it up. A missing, painted-over or faulty isolator is a genuine safety issue and a common snag — fitting or fixing one is a licensed electrician's job.
Related terms
RCBO (Residual Current Breaker with Overload)
A single protective device that combines an MCB and an RCD — it trips on both overload/short-circuit AND earth leakage, protecting one circuit on its own.
MCB (miniature circuit breaker)
The switch in your board that trips to cut power when a circuit is overloaded or short-circuits.
Distribution board (DB)
The panel of breakers that splits your home's power into separate circuits — the first place to look when something trips.
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