What Tests Does Your Electrician Run Before Switching Your Power Back On?

What tests does an electrician actually run before switching your power back on? Before any new circuit, switchboard or consumer mains connection is energised, a licensed electrician has to run a full sequence of verification tests under AS/NZS 3000, checking earthing, insulation, polarity, safety switch operation and fault loop impedance, plus a visual inspection of the whole installation. Only once every test passes does the work get sealed, energised and signed off with a compliance certificate.

⚡ Quick Answers: Test and Commissioning

• What is test and commissioning? The set of checks a licensed electrician must complete on new or altered wiring before it can be safely energised and handed over.
• Do I need this for every job? Yes. AS/NZS 3000 makes verification testing mandatory on any new installation or alteration, from a single power point to a full switchboard upgrade.
• What is an insulation resistance test? A check that the insulation on your wiring is intact, with a minimum acceptable reading of 1 megohm between live conductors and earth.
• What does earth fault loop impedance testing check? That your protection will disconnect a fault fast enough to prevent electric shock, measured at the point furthest from the switchboard.
• Why are my meter and switchboard sealed after the work? A tamper evident seal proves the installation was verified compliant at handover and hasn't been altered since.
• Who has to do this testing? Only a licensed electrician, using calibrated test instruments, can sign off verification testing and issue the compliance certificate.

1. Visual inspection comes first

Before a single test instrument comes out, your electrician visually inspects the completed work: correct cable selection and support, proper terminations, labelling, clearances from other services, and that everything matches the design. This isn't a formality. A visual check catches obvious problems, like a loose gland or a missing cover, that testing alone wouldn't necessarily flag, and it has to be done before testing under AS/NZS 3000.

2. Continuity of the earthing system

Your earthing system is what makes a safety switch or circuit breaker actually protect you. Testing proves the main earthing conductor, protective earthing conductors and any bonding conductors are continuous and low enough in resistance to let fault current flow and trip the protective device. If a fault develops between a live part and an earthed metal case, an intact earthing system stops that case from becoming dangerous to touch, and the main earthing conductor has to measure well under one ohm.

3. Insulation resistance test

This is the test most homeowners have heard of by name, sometimes called a megger test. Your electrician applies a test voltage between the live conductors and earth and measures the resistance of the insulation around your cables. Under AS/NZS 3000 Clause 8.3.6, that reading has to be at least 1 megohm. A low reading points to damaged, aged or wet insulation, which can cause shock hazards, fires from short circuits, or equipment damage, so it gets fixed before anything is energised.

4. Polarity and correct circuit connections

Polarity testing confirms your active, neutral and earth conductors are connected exactly where they should be, at every socket outlet, switch and light fitting. A reversed active and neutral, or an active landing on an earth terminal, can leave equipment live when it should be switched off, which is exactly the kind of fault this test exists to catch. Correct circuit connections testing goes a step further, confirming there's no short between conductors and no crossed wiring between two different circuits sharing the same switchboard.

5. Verification of safety switch (RCD) operation

Every residual current device, what most Sydney homes call a safety switch, gets tested after installation using its integral test button or dedicated test equipment, confirming it actually disconnects power the way it's designed to. Your electrician also verifies that all switched poles isolate properly once the safety switch trips. This is separate from the monthly push button test you can do yourself; the commissioning test is the formal verification that the device was installed and is functioning correctly in the first place. If you've ever wondered what the difference is between a circuit breaker and a safety switch, this is where that distinction actually gets checked.

6. Earth fault loop impedance test

Where a socket outlet circuit relies on automatic disconnection rather than a 30 milliamp safety switch, your electrician measures the earth fault loop impedance at the point furthest from the switchboard. This confirms the whole path, live conductor, earth path and the connection back to the supply, will let enough fault current flow to trip the protective device within the required time. It's a technical test most homeowners never see performed, but it's what stands behind the promise that a fault will be cleared quickly rather than left live.

7. Sealing the equipment

Once every test has passed, your electrician (or the network distributor, depending on what's been worked on) applies a numbered tamper evident seal to the meter panel, service fuse and any other equipment covered by network rules. That seal is physical evidence the installation was verified compliant at handover, and that nobody has opened it since without authorisation. If you ever see a broken or missing seal on your meter box, treat it the same way as a missing compliance certificate: worth having checked.

Why This Matters for Your Compliance Certificate

Every one of these tests feeds directly into the Certificate of Compliance for Electrical Work (CCEW) issued at the end of the job, a formal declaration that this exact sequence was carried out and passed. For work touching your point of connection, such as new or upgraded consumer mains, the same verification principles apply before Ausgrid, Endeavour Energy or Essential Energy will allow the connection to be energised, which is why this crosses into Level 2 ASP territory upstream of your meter. Not sure which network you're on? Check your network area in seconds with our postcode checker.

Worth being clear about what this isn't: test and commissioning verifies new or altered wiring at the point it's installed, a different job to test and tag for portable appliances, an ongoing workplace safety routine for plug in equipment rather than a one off verification of fixed wiring.

How High Demand Electrical Helps

Every job High Demand Electrical completes, from a single new circuit to a full switchboard upgrade or consumer mains replacement, goes through this same testing sequence before we hand it back to you, with a proper compliance certificate to match. We're a licensed local team, not a call centre, and one of Sydney's most trusted Level 2 ASPs. If you've inherited an older installation and aren't sure it would pass this kind of testing today, an electrical safety inspection is the way to find out.

Test and Commissioning FAQs (Sydney)

Do I get to see the test results?

Yes. Your compliance certificate and test records should be provided at the end of the job. Keep them as proof of what was checked and when, useful if you ever sell the property or lodge an insurance claim.

What happens if a test fails?

The fault gets rectified first, then that test and any earlier test it could have affected gets repeated. Nothing gets energised or signed off until every mandatory test passes.

Does a simple job like a new power point still need all this testing?

Yes. AS/NZS 3000 doesn't scale the testing requirement to the size of the job; a single new power point still needs earth continuity, insulation resistance, polarity and RCD verification carried out correctly.

My safety switch keeps tripping, does that mean the original testing was wrong?

Not necessarily. A properly tested and commissioned safety switch can still trip later from a new fault, like moisture ingress or a failing appliance. See our guide on why your safety switch keeps tripping for the common causes.

Can I do any of this testing myself?

The monthly push button test on your safety switch is fine to do yourself. Every other test in this sequence requires calibrated instruments and a licensed electrician to perform and sign off.

Book a Compliant Installation in Sydney

Call High Demand Electrical on 0402 559 777 for switchboard upgrades, new circuits or a full electrical safety inspection, every job tested, commissioned and certified properly. A short site assessment confirms the scope and price before any work is locked in.