Before starting, make sure your equipment is meeting all legal safety standards.
Always ensure that the Voltage Indicators (VI) you are using comply with BS EN61243-3, such as the VI13800 voltage indicator from Martindale Electric, which has been specifically designed to meet this standard.
Identify the point of isolation – lock it off and place warning tags onto the equipment.
A basic lock-off kit should include a selection of MCB Lock Off
devices, a padlock with a unique key, a hasp if more than one
person is working on a system as well as lock-out tags and
Test your VI against the proving unit to make sure it is working properly.
It is recommended to use a dedicated proving unit matched to the VI to fully test that all LEDs on all ranges are working. A proving unit is safer than the mains and provides a live source wherever you are working.
Use your VI to make sure dangerous voltage levels are not in the circuit you are about to work on.
The next step is to test for dangerous voltages on any circuit conductor to be worked on, whether single or three-phase. Verify that the circuit you intend to work on, is the correct circuit which you have safely isolated.
Prove the VI against the proving unit again before starting to
work on the circuit.
Re-test your VI is functioning and working correctly to make
sure that no damage has occurred, or fault appeared on your