How to find what is tripping your circuit breaker

⚡ How to find what is tripping your circuit breaker

What is the primary cause of a circuit breaker tripping in Australian homes?

Electrical work in Australia must be performed by a licensed electrician. This guide is for understanding the process and selecting the right tools and materials.

If a circuit breaker keeps tripping, the cause is usually an overloaded circuit, a faulty appliance, a damaged lead, moisture ingress, or a wiring fault on the circuit. This guide gives Australian homeowners a safe, structured process to identify whether the problem is likely appliance-related or whether it needs a licensed electrician under AS/NZS 3000 Wiring Rules.

What skill level is required to safely identify a tripping circuit breaker?

Beginner — Estimated time: 0.5 to 1.5 hours

What essential tools are needed to diagnose a tripping circuit breaker?

What materials are necessary for safely troubleshooting a tripping circuit breaker?

What are the critical safety requirements when dealing with a tripping circuit breaker?

Step-by-Step Guide

Step 1: Identify which device has tripped

Go to the switchboard and look for the switch that is in the down position or sitting between ON and OFF.

Check whether the tripped device is:

This matters because the type of device gives you a clue:

💡 If your switchboard labelling says things like “power”, “lights”, “oven”, “A/C”, “HWS”, or “shed”, write down exactly which one is affected before you start.

Step 2: Switch off and isolate the affected circuit

Turn the tripped breaker fully OFF first before trying to reset it.

If it controls socket outlets, unplug everything on that circuit:

If it controls fixed equipment like lights, ovens, hot water, air conditioning, pumps or smoke alarms, note that these may need a licensed electrician to isolate or test further.

💡 Many nuisance trips come from one faulty portable appliance or damaged extension lead rather than the house wiring itself.

Step 3: Check for obvious overload

Think about what was running when the breaker tripped.

Common overload combinations on one circuit include:

A typical general power circuit in Australia may be wired in 2.5mm² TPS and protected by a breaker sized to suit the installation. If too many high-load appliances run together, the breaker can trip.

Reset the breaker with everything unplugged. If it now stays on, overload or one appliance is likely the issue.

Step 4: Reset the breaker correctly

Stand to the side of the switchboard, look away slightly, and use one hand where practical.

To reset:

If it trips immediately with all appliances unplugged, stop there.

This usually points to:

At this stage, a licensed electrician should test the circuit.

Step 5: Reconnect appliances one at a time

If the breaker stays on with everything unplugged, plug appliances back in one by one.

After each appliance:

Start with the most likely problem items:

If the breaker trips when one item is plugged in or switched on, that appliance or its lead is a strong suspect.

💡 Portable heaters and kettles are frequent causes because they draw high current and can also develop internal faults.

Step 6: Inspect the suspected appliance and lead

With the appliance unplugged, inspect:

Do not use the appliance again if you see any damage.

A tripping RCD/RCBO can be caused by small leakage to earth from:

Step 7: Check outdoor and wet-area equipment carefully

If the tripping happens in rain, after watering, or only when outdoor equipment is connected, moisture is a likely cause.

Common culprits:

Unplug all outdoor equipment and dry accessible plugs and sockets externally only. Do not open accessories or fittings.

If the breaker then holds, the fault is likely in one of those outdoor items or accessories. Outdoor circuit faults often require an electrician to insulation test and inspect IP-rated fittings.

Step 8: Rule out power board and extension lead faults

A damaged power board or lead can trip a breaker just like a faulty appliance.

Inspect for:

Replace suspect leads rather than continuing to test with them.

💡 Cheap or old power boards are common fault sources, especially in garages, sheds and home offices.

Step 9: If lights are tripping, reduce the problem area

If a lighting circuit is tripping, switch off all light switches on that circuit and reset the breaker.

Then turn lights back on one by one.

This can help narrow the fault to:

Lighting circuits are commonly wired in 1.5mm² TPS, but fault-finding still requires caution because fixed wiring and fittings should only be opened and repaired by a licensed electrician.

Step 10: Know when to stop and call an electrician

Call a licensed electrician immediately if:

An electrician may use proper test equipment to confirm whether the fault is with the installation, a fixed appliance, or a portable appliance.

Common Mistakes to Avoid

Pro Tips

Recommended Tools

🔒 Licensing

Electrical work in Australia must be performed by a licensed electrician. This guide is for understanding the process and selecting the right tools and materials.

Licensing and compliance requirements vary by state:

For any repair, replacement of wiring accessories, switchboard work, testing inside enclosures, or fault rectification on fixed wiring, use a licensed electrician and ensure work complies with AS/NZS 3000 and applicable state regulations.

🔧 Recommended Tools