Safety Switches & RCDs in Melbourne
A safety switch — known technically as an RCD — is the single most important device in your switchboard for preventing electric shocks. We install Type A RCBOs on every final sub-circuit for maximum protection and convenience.
What Is a Safety Switch?
"Safety switch" is Australian slang for an RCD — a Residual Current Device. It monitors the balance of current flowing through your circuit. If it detects even a tiny imbalance (as low as 30 milliamps), it cuts power within 30 milliseconds. That's fast enough to prevent serious injury or death from an electric shock.
Every modern Australian switchboard must have RCD protection. Since April 2023, that protection must be Type A — the higher standard that detects both AC and pulsating DC fault currents.
Evolution of Circuit Protection
Electrical protection has evolved significantly over the decades. Understanding the difference helps explain why modern RCBOs are the best choice:
- Ceramic fuses — the original protection. A thin wire melted under overload, cutting power. No shock protection, had to be replaced after every blow, and could be dangerously "fixed" with a coin or nail.
- Circuit breakers (MCBs) — replaced fuses in the 1970s. Automatically trip on overload or short circuit, reset with a flick. Better than fuses, but still no shock protection.
- RCDs (safety switches) — added shock protection in the 1990s. One RCD can protect multiple circuits, but when it trips, all those circuits lose power together. Nuisance tripping is common — a fault on one circuit knocks out the rest.
- RCBOs — the modern standard. Combine a circuit breaker and an RCD in one unit. Each circuit gets individual overload AND shock protection. When one trips, only that circuit is affected. No more whole-house blackouts from a single fault.
Type AC vs Type A — Why Type A Is Mandatory
Not all safety switches are equal. There are two main types, and the difference matters if you have modern electrical equipment:
Type AC detects alternating current (AC) fault currents only — the kind you get from a faulty power point or damaged cable. This was the standard for decades.
Type A detects both AC fault currents and pulsating DC residual currents. This is critical because many modern devices create pulsating DC leakage — solar inverters, EV chargers, LED drivers, variable speed drives (VSDs), and even some laptop chargers. A Type AC safety switch can miss these faults entirely.
Since April 2023, AS/NZS 3000:2018 Amendment 2 has made Type A mandatory for all new installations and switchboard upgrades in Australia. There is no reason to install Type AC today.
What Is an RCBO?
An RCBO combines a circuit breaker (MCB) and a safety switch (RCD) into a single compact unit. That means every circuit in your home gets both overload protection (against fires from overloaded wires) and shock protection (against electric shocks) — individually.
We use Voltex RCBOs — Australian-made, engineered for Australian conditions, with a fantastic warranty. Unless a circuit has a specific exception that warrants different protection, every final sub-circuit should be on an RCBO.
RCBO vs RCD — Why RCBOs Are Best Practice
The difference between an RCBO and a traditional RCD comes down to one thing: selective tripping.
With a traditional RCD, multiple circuits share one safety switch. If a fault occurs on any of those circuits — say a damp plug in the bathroom — the RCD trips and all protected circuits lose power. You could lose lighting, kitchen appliances, and air conditioning because of one faulty outlet. This is called nuisance tripping, and it's frustrating.
With RCBOs, each circuit has its own protection. If the bathroom circuit trips, the kitchen, living room, and air conditioning keep running. Only the faulty circuit is affected. Better safety, less disruption, easier fault finding.
What to Expect
Frequently Asked Questions
What's the difference between a safety switch and an RCD?
Type AC vs Type A — which do I need?
What is an RCBO and do I need one?
I have solar panels or an EV charger — does this change what I need?
My safety switch keeps tripping — what does that mean?
Premium Service,
Quality Results,
Since 1963.
Over 63 years of trusted service across Melbourne
