HSE Guidance Note GS38 requirements for test probes, leads and voltage indicators, and the prove–test–prove sequence that proves a circuit dead.
Exposed metal tip not exceeding 4 mm (2 mm or less is strongly recommended); finger barriers or shaped guards to prevent the hand slipping onto live metal; leads to BS EN 61010-031 with a two-pole voltage detector to BS EN 61243-3.
HSE Guidance Note GS38 (4th ed)
Test leads and probes should be protected by an hbc fuse, current rating usually not exceeding 500 mA (a higher rating, typically 10 A, applies to a loop-impedance or RCD tester), or a current-limiting resistor and fuse.
HSE Guidance Note GS38 (4th ed)
CAT II — circuits directly connected to the installation, such as appliances and portable tools. CAT III — the building's fixed installation, such as distribution boards and socket-outlets. CAT IV — the source or origin of supply, such as meters and the main fuse.
| Category | Where it applies | Examples |
|---|---|---|
| CAT II | Circuits directly connected to the installation | Appliances, portable tools |
| CAT III | The building's fixed installation | Distribution boards, socket-outlets |
| CAT IV | The source or origin of supply | Meters, the main fuse |
HSE Guidance Note GS38 (4th ed)
Prove the voltage indicator works on a known live source or a proving unit, use it to test the circuit is dead, then prove the indicator again on the known live source to confirm it has not failed during the test.
HSE Guidance Note GS38 (4th ed)
