Treat the lead as safety equipment
An extension lead carries the tool's full current. Cuts, crushing, loose connections, moisture and unsuitable selection can cause shock, burns or fire. Do not solve inadequate permanent wiring by daisy-chaining leads and adapters; assess the tool, supply, environment, route and duration.
Match the tool to the supply
Check the tool rating plate and manual. HSE advises confirming voltage and that the supply can provide the required current. Cable rating depends on load, total length, installation, temperature and whether a reel is coiled; follow the product instructions and have circuit capacity checked when uncertain.
Preserve grounding
OSHA calls for three-wire extension sets where grounding is required. Never remove the grounding pin or bypass it with an unsuitable adapter. Double insulation does not make a damaged lead or wet connector safe. Remove cracked plugs, loose sockets and missing pins from service.
Use an RCD as a secondary layer
A suitable RCD or GFCI can disconnect some leakage faults rapidly. Test portable devices as their maker directs before use. It does not detect every fault or replace sound equipment; repeated tripping requires isolation and competent investigation, never bypassing the device.
Protect against water and traffic
Keep connectors out of water and use equipment rated for the environment. Do not trap leads in doors, staple them, run them over sharp metal or leave them in vehicle and pedestrian routes. NIOSH recommends routing away from foot traffic to prevent trips and damage.
Inspect before every shift
With power disconnected, inspect the full length for cuts, crushing, heat, taped repairs, exposed conductors, loose strain relief and damaged pins. Recheck after run-over, impact, wetting or protective-device operation. Tag and isolate defects for competent repair or replacement.
Connect and disconnect correctly
Start with the tool switched off and keep joints free from tension, sparks, dust and hot surfaces. Pull the plug body, not the cable. Avoid linked extension leads; choose one correctly rated length and keep total multi-outlet load within its marking.
Store and record safely
Disconnect, cool, dry-clean and coil in broad natural loops. Store plugs away from moisture, oil and swarf. Risk-based inspection and competent electrical testing remain necessary; record faults and withdrawal decisions to identify recurring damage.