3.2.3 Switching for mechanical maintenance

Mechanical maintenance is taken as meaning the replacement and repair of non-electrical parts of equipment, as well as the cleaning and replacement of lamps. Thus, we are considering the means of making safe electrical equipment which is to be worked on by non-electrical people.

Such switches must be:

1. - easily and clearly identified by those who need to use them
2. - arranged so that there can be no doubt when they are on or off
3. - close to the circuits or equipment they switch
4. - able to switch off full load current for the circuit concerned
5. - arranged so that it is impossible for them to be reclosed unintentionally.

Where mechanical maintenance requires access to the interior of equipment where live parts could be exposed, special means of isolation are essential. Lamps should be switched off before replacement.