The extension lead is the most abused cable in any home or workshop, and the one most likely to start a fire when it is used carelessly. A few habits keep it safe.
Unwind it before a heavy load
A lead left coiled on its drum cannot lose heat. Each turn warms the next, and under a heavy load the middle of the coil can reach a temperature that softens the insulation while the socket still reads normal. Fully unwind a lead before running a heater, a pump or any high-current tool through it, and read the drum’s rating, which is often lower for the coiled condition than for the uncoiled one.
Match the rating and do not chain leads
Check that the lead’s current rating is at least the load it will carry, and never plug one extension lead into another. Chaining multiplies the joints, the resistance and the voltage drop, and it hides how much load the first lead is really carrying.
Use the right cable outdoors
Ordinary indoor flex is not made for sunlight, water or being dragged over rough ground. Outdoor tools need a tough-sheathed flexible cable and an earth-leakage (RCD) protected supply, and every lead should be checked for cuts and crushed sections before use. APAR light-duty and flexible cables and braided cables and wires are built for the flexing and abrasion portable use demands.