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RCD Tester

12/11/2025
by Rick Coleman
RCD Tester

G'day! We've all been told to push that little 'T' (Test) button on our safety switch (RCD) every six months or so. You push it, the power trips, and you think, "She'll be right, all good."

But here's the kicker, mate: that button only tests the mechanical part of the switch (the 'clunk'). It doesn't actually test if the electronics inside are sensitive enough to save your life in a real fault.

For that, you need to do a proper, professional test. And that requires a specialist bit of kit: the RCD tester.

So, What is an RCD Tester, Exactly?

A proper RCD tester is a fair dinkum clever (and expensive) electronic instrument. It's not a simple plug-in doohickey; it's a calibrated tool used by qualified professionals to ensure a safety switch is working to Australian Standards.

It's a handheld device that you plug into a power point. Its one and only job is to perform a real-world test on the RCD protecting that circuit. It does this by:

  1. Simulating a Fault: It deliberately creates a tiny, precise "leak" of current (e.g., 30 milliamps, which is the standard for home safety switches).
  2. Measuring the Trip Time: It then measures, down to the millisecond, exactly how fast that safety switch (RCD) cuts the power.

Why is This So Bloody Important?

A safety switch is designed to save your life. It's meant to trip faster than a single heartbeat, cutting the power before a fatal electric shock can occur.

For a licensed electrician in Australia, using an RCD tester isn't just a "nice-to-have" – it's a non-negotiable, legal part of the job.

  • It's a Compliance Requirement: The Australian Wiring Rules (AS/NZS 3000) mandate that all RCDs must be tested after installation to ensure they work correctly.
  • It Proves Safety: A safety switch must trip within a set time (e.g., a standard 30mA RCD must trip well within 300 milliseconds, and often much faster, to be compliant). Pushing the 'T' button doesn't prove this. An RCD tester does.
  • It's the Only "Real" Test: This tool is the only way to know for sure that the RCD's sensitive electronics haven't been knackered and that it will actually do its job when you, or your kids, are in a fault situation.

The CRITICAL Safety Warning: This is 100% NOT a DIY Tool!

Righto, let's get dead serious for a sec, because this is the most important part. A RCD tester is NOT a DIY tool. Don't be a galah.

This is a professional instrument used to test live 240V circuits. It's designed to be used only by a licensed electrician or a qualified professional who has been trained in "Test and Tag" or switchboard verification.

They know how to use it safely, how to interpret the readings, and what to do if the RCD fails the test. Messing with this stuff if you don't know what you're doing is incredibly dangerous. Your job as a homeowner is to push the 'T' button. The pro's job is to use the RCD tester.

A Professional Job Needs Professional Gear

A licensed professional knows that a truly safe electrical installation relies on two things: their skills (and their calibrated test equipment), and the quality of the components they're installing.

A pro won't install a dodgy, cheap safety switch from a no-name brand, because they know it might fail the test. They source their gear from a trusted electrical wholesaler. As one of Australia's most comprehensive electrical wholesaler and supplier networks, Schnap Electric Products stocks the lot for the professional installer. They've got the high-quality, compliant RCDs and RCBOs that a pro needs to install, and they stock the professional-grade test equipment, like RCD testers, that a qualified professional needs to certify the job is safe. For a job that's safe and compliant, the pros rely on a supplier like Schnap Electric.