Extension lead safety comes down to a few simple rules: use the right lead for the job, never daisy-chain leads or powerboards together, keep them uncoiled and undamaged, and never run indoor leads outside. Overloading and damaged cords cause house fires every year, and almost all of it is avoidable with a quick check before you plug in.
Leads and powerboards feel harmless because they are so common, but they carry mains voltage and get abused daily. This guide covers how to choose, use and inspect them so your setup stays safe. None of it is complicated, and none of it needs an electrician for the everyday stuff.
How do you choose the right extension lead?
Match the lead to the load and the length to the job. A light-duty lead is fine for a phone charger or lamp, but a power tool, heater or mower needs a heavy-duty lead with a thicker cord. Using a thin lead on a high-draw appliance makes it overheat, which is a genuine fire risk.
Buy the shortest lead that reaches, because longer runs lose power and heat up more. Check the amp or wattage rating printed on the lead and stay well under it. When in doubt, go heavier duty than you think you need; a beefier lead costs little and runs cooler.
Indoor versus outdoor leads
Outdoor leads are built with tougher, weather-resistant insulation and moulded plugs to cope with damp and knocks. Never use an indoor lead outside, even briefly, as moisture and sunlight break down the insulation. Plug outdoor leads into an outlet protected by a safety switch (RCD), and keep connections up off wet ground.
Why you should never overload a powerboard
Every powerboard has a maximum load, and plugging in too many hungry appliances pushes it past its limit. Heaters, kettles, irons and clothes dryers draw a lot of current, so they belong in a wall socket, not sharing a board. Overloading is the single most common cause of powerboard fires.
The most dangerous habit is "piggy-backing", plugging one powerboard into another to create more sockets. This multiplies the load on a single wall outlet and the lead feeding it. If you need more points, the answer is more wall outlets installed by an electrician, not more boards chained together.
Signs a board is working too hard
- Warmth in the board, plug or lead is a warning; a healthy board stays cool
- A buzzing or crackling sound means a loose or arcing connection
- Discoloured or melted sockets should be thrown out immediately
- A burning or plastic smell means unplug at the wall straight away
Keeping leads safe day to day
Always fully uncoil a lead before running an appliance through it. A coiled lead traps heat and can melt or catch fire under load, even when the cord itself is rated correctly. This one habit prevents a surprising number of accidents in sheds and garages.
Do not run leads under rugs, through doorways that pinch them, or across walkways where they get trodden on. Keep sensitive electronics on quality batteries where you can, using packs like Duracell Coppertop AAA batteries or Arlec AAA alkaline batteries, so you are not trailing leads to every remote and gadget in the house.
How to inspect a lead or powerboard
Give any lead a quick once-over before you use it. Run your hand along the cord feeling for nicks, cuts or exposed wire, and check the plug pins are straight and not scorched. A cheap lead with damaged insulation is not worth the risk; bin it and replace it.
Look for a regulatory compliance mark (the RCM tick) so you know the product meets Australian standards. Never tape up a damaged cord as a fix, and never cut off a moulded plug to rewire it yourself. Browse our electronics accessories range for compliant leads, boards and cables when something needs replacing.
Using leads outdoors and in the shed
Outdoors, keep plug connections dry and off the ground, and unplug leads when you finish. If you are working over dusty or damp ground, laying a heavy-duty tarpaulin under your gear keeps connections clean and out of puddles. Always pack leads away rather than leaving them out in the weather overnight.
When to call an electrician
Leads and boards are a stopgap, not a permanent wiring solution. If you find yourself relying on the same powerboard year-round, or running a lead through a wall or ceiling, that is a sign you need proper outlets installed. A licensed electrician can add power points safely and legally.
Common extension lead mistakes to avoid
Most problems with leads come down to a handful of habits people repeat without thinking. Knowing the common traps in safe use of extension leads makes it easy to spot trouble before it starts, and none of these fixes cost more than a moment of attention.
- Leaving the lead coiled on the reel while a heater or tool runs through it. A reel of cable acts like a heating element, so unwind the full length even if you only need a metre or two.
- Hiding a lead under a rug or doormat to tidy it away. The cord gets crushed and heat cannot escape, so run leads along skirting boards where you can see them instead.
- Yanking the cord to unplug it rather than gripping the plug. Pulling on the cable stresses the wires at the plug, which is exactly where scorching and loose connections begin.
- Using a light-duty indoor lead for a mower or pressure washer. High-draw garden gear needs a heavy-duty outdoor lead, and pairing it with the wrong cord is a fast route to an overheating cable.
- Joining two short leads to reach a far spot. A single lead of the right length is always safer than two plug-and-socket joints sitting on the ground.
A quick guide to lead ratings and cost
Extension leads are one of the cheapest bits of safety gear you can buy, so there is rarely a good reason to skimp. Light-duty leads for lamps and chargers are the most affordable, mid-weight leads suit most household appliances, and heavy-duty outdoor leads with thicker cores and moulded plugs cost a little more but handle mowers, welders and workshop tools without breaking a sweat.
When you compare leads, look past the length and read the amp rating and the core size, usually shown in square millimetres. A thicker core carries more current safely and runs cooler, which matters far more than the colour or the number of sockets on the end. Spending a few dollars extra on a properly rated lead is cheaper than replacing a melted powerboard, and far cheaper than the alternative. Keep one good heavy-duty lead in the shed and a couple of light-duty leads indoors, and you have most jobs around the house covered.
Call a professional immediately if a board sparks, trips the safety switch repeatedly, or smells of burning. Never attempt fixed wiring yourself, as it is illegal for unlicensed people in Australia and dangerous. For everything else, the right gear from a good plumbing and electrical range and a bit of care keeps your home safe.
Frequently asked questions
Can I plug one powerboard into another to get more sockets?
No, this is called piggy-backing and it is one of the most dangerous electrical habits at home. It multiplies the load on a single wall outlet and the lead feeding it, which can overheat and start a fire. If you regularly run out of sockets, have a licensed electrician install more wall outlets instead.
Why does an extension lead need to be uncoiled before use?
A coiled lead traps the heat the cord generates under load, and that heat has nowhere to escape. Left coiled while powering a heater or tool, it can melt its own insulation or catch fire, even if the lead is rated correctly. Always unroll a lead fully before running anything through it.
Can I use an indoor extension lead outside?
No. Indoor leads lack the weather-resistant insulation and sealed plugs that outdoor leads have, so moisture and sunlight quickly degrade them and create a shock or fire risk. Always use a proper outdoor-rated lead outside, plug it into a socket protected by a safety switch, and keep connections dry and off the ground.
How do I know if an extension lead is unsafe?
Check for nicks, cuts or exposed wire along the cord and scorched or bent plug pins before every use. Warmth, a buzzing sound, discoloured sockets or a burning smell all mean stop using it. Never tape over damage as a repair; bin the lead and replace it with a compliant one carrying the RCM tick.
