Extension leads are a normal, safe part of most homes — used correctly. The risk comes from overloading a lead beyond its rated capacity, daisy-chaining multiple leads together, or running high-draw appliances through a lead not built for them. Understanding the difference is the whole safety question.
Know the rating
Every extension lead has a maximum current or wattage rating printed on the plug, the lead itself, or its packaging. Adding up the wattage of everything you plan to plug into it and checking that against the rating takes thirty seconds and is the single most useful thing you can do to use one safely.
What is genuinely fine
- Running a lamp, phone charger, TV, or similar low-draw electronics through a standard extension lead.
- Using a properly rated lead temporarily for a vacuum cleaner, power tool, or similar moderate-draw device.
- Using an extension lead outdoors, provided it is specifically rated for outdoor or damp-location use.
- Leaving a correctly used, undamaged lead plugged in for extended periods, provided nothing on it is overloading it.
What to avoid
| Practice | Why it is risky |
|---|---|
| Daisy-chaining multiple extension leads together | Compounds the load on the first lead in the chain and multiplies the number of connection points that can loosen or overheat |
| Running space heaters, microwaves or other high-draw appliances through a lead | These commonly exceed a standard lead’s rated capacity on their own |
| Using an indoor-only lead outdoors or in damp conditions | Not designed to handle moisture, risking a serious shock or short |
| Running a lead under a rug or carpet | Traps heat that would normally dissipate, and hides damage from being noticed |
| Using a lead with a cracked casing, exposed wire, or a loose plug | Direct path to a short circuit or shock |
| Treating a lead as permanent household wiring | Extension leads are designed for temporary use, not as a substitute for adding an outlet |
Warning signs to act on immediately
- The lead or plug feels warm or hot to the touch during normal use.
- Any burning smell near the lead or the outlet it is plugged into.
- Discolouration, melting, or scorch marks on the plug or casing.
- The lead trips a breaker or GFCI outlet repeatedly.
If any of the above happens, unplug the lead, do not use it again, and dispose of it. A damaged or overloaded extension lead is not worth troubleshooting — replacements are inexpensive relative to the risk.
