Repair work may consist of the following stages:
- fault location
- fault rectification and/or replacement of components
- recommissioning the repaired part of the installation
Different procedures may need to be applied at each stage of the work.
Specific working conditions shall be defined when locating and confining defects with the installation energised or during application of test voltages according to Operational procedures or based on Working procedures.
Elimination of defects shall be carried out in accordance with the rules of working procedures.
Appropriate functional and verification tests and necessary adjustments shall be performed to ensure that the repaired parts of the installation are suitable for re-energisation.
Replacement work
Replacement of fuses
Generally, the replacement of fuses should be carried out dead unless a safe procedure is followed to replace them live.
For low voltage installations, if the fuse is fitted in a device protecting the person against direct contact and the possible occurrence of short-circuit, the replacement may be carried out without verifying the absence of voltage and by an instructed person.
For high voltage installations, the replacement shall be carried out according to the appropriate working procedures by a skilled person.
Replacement of lamps and accessories
The replacement of lamps and withdrawable accessories such as starters should be carried out dead – but where necessary, based on risk assessment, it may be done live.
For low voltage installations, these replacements may be carried out live where the equipment provides protection against contact (minimum IP2X or IPXXB).
In all other cases and especially in the case of high voltage installations replacement shall be carried out in accordance with repair procedures.
Replacement of non-withdrawable accessories shall be carried out in accordance with the working procedures.
Care shall be taken to ensure that the replacement parts used are suitable for use in the equipment being maintained.