Home Electrical Safety

Extension lead safety: avoid overloads, heat build-up and fire risk

Extension leads are useful, but they are often misused. Overloading, daisy chaining, damaged cables and using high-power appliances through cheap leads can create real fire risk.

Safety guidance

This TESC guidance page is designed to help households, landlords, agents and property managers recognise avoidable electrical risks before they become incidents.

Product safety is separate from an Electrical Installation Condition Report. An EICR assesses the fixed electrical installation, while plug-in equipment, chargers, extension leads and portable products can introduce additional risks after the installation itself has been inspected.

What to look for

Key issues, warning signs and safer practice.

Common extension lead risks

  • Plugging one extension lead into another extension lead.
  • Running high-power appliances such as heaters through multiway adaptors.
  • Using cable reels while still wound up, trapping heat inside the reel.
  • Using damaged, crushed, loose or scorched extension leads.
  • Running leads under carpets, rugs, doors or furniture where damage can be hidden.

High-load appliances to treat carefully

  • Electric heaters.
  • Tumble dryers and washing machines.
  • Kettles, microwaves and cooking appliances.
  • Portable air conditioners.
  • Power tools and workshop equipment.

Safer use

  • Use one extension lead per socket and avoid daisy chaining.
  • Fully unwind cable reels before use.
  • Do not cover leads or run them where they can be crushed.
  • Check plugs and sockets for heat, browning or burning smells.
  • If you permanently need more sockets, consider proper fixed electrical alterations by a competent electrician.

When electrical products should be taken out of use

Stop using an electrical product if it shows signs of overheating, melting, burning smells, loose connections, damaged cables, exposed parts, buzzing, cracking, smoke or repeated tripping. Do not keep testing a suspect product to see whether it happens again.

Where the concern relates to fixed wiring, sockets, consumer units, earthing, RCD protection or repeated circuit faults, the matter should be checked by a competent electrical contractor rather than treated as only a product issue.

Useful TESC links

Common questions

It can be. Daisy chaining increases the chance of overload, poor connections and overheating.

It is better to plug high-load heaters directly into a suitable wall socket. Cheap or overloaded extension leads can overheat.

An EICR covers the fixed electrical installation. Extension leads are portable equipment, but their misuse can still create serious electrical safety risks.

Electrical safety records matter

Product safety, fixed wiring safety and compliance records all work together. Use TESC resources to understand electrical risks, check EICR records and find registered providers where inspection or remedial work is needed.