Every year people working on construction suffer electric shock and burn injuries, some of which are fatal.  It is only safe to work on electrical equipment after all sources of energy have been securely isolated and any stored energy has been released from the equipment.

A fundamental principle is that the point of isolation should be under the control of the person who is carrying out the work on the isolated conductors. It is important that there is no chance that a source of energy can be deliberately or inadvertently re-connected to the equipment whilst it is being worked on. This can be achieved by applying a lock to each isolation device, and the person doing the work should have all the keys to these locks in his or her possession.

This message addresses the need to lock off distribution boards prior to carrying out work on switches and sockets.

Further information:

A section on the HSE web site gives guidance on the use of electricity in construction (www.hse.gov.uk).

This message should be applied onto domestic distribution boards, in a highly visible location. It is important to ensure that other security warnings are not covered.

Messages should be printed on laminated synthetic labels with an extra strong permanent adhesive backing to ensure long term adhesion.