City and Guilds 2330 Certificate in Electrotechnical Technology Level 3 Unit 3 Outcome 1 Session 6 Factors affecting repair or replacement B & B Training Associates
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Unit 3
Installation (Buildings and Structures) Fault Diagnosis and rectification
Outcome 1
Select and apply fault diagnosis and rectification techniques
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Outcomes from this session At the end of this session you should be able to
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Describe factors which influence repair or replacement
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Review of previous sessions
Control circuits deal with the controlling of motor starters etc.
Lighting circuits deal with lighting.
Fire and emergency lighting circuits are easy to recognise.
Faults occur for many reasons, they need to be understood and rectified.
The person who is working must be competent to do the task.
Tasks should be planned so that no live working takes place.
An approved voltage tester and a voltage proving unit are required for testing of a potentially live piece of equipment.
There are three key aspects to good fault finding practice, good technical knowledge, good personal experience and a logical approach.
In any fault diagnosis process the evidence must be gathered, analysed and interpreted.
When the fault has been found it must be rectified, and re-tested before putting the circuit back into commission.
Care should be taken when turning the supply back on.
Faults can be listed as inherent faults, or faults caused by negligence etc.
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Repair or Replace? There are a number of factors to consider when a fault appears on an installation.
Cost of replacement – Not only the purchase cost, but also the cost of labour
Availability of replacement – How quickly can the replacement item be found and replaced? – Is the replacement compatible with existing equipment?
Downtime during the fault and repair. – How much production is lost, how is the repair time to be managed?
Availability of staff and resources. – Is the labour in place to safely and efficiently repair the fault?
Legal responsibility. – This includes warranties and requirements of licensing authorities and H&S legislation.
Access to parts of the installation – Access may be only available at certain times for production or H&S reasons – Safety implications of isolation
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Legal Responsibilities The Electricity At Work Regulations 1989 places responsibilities on a number of people, including electricians. When a fault occurs and nothing is done about it by the client, then he/she (the client) is responsible in law for himself, his workers, and anyone who visits the place of operation. If the client calls an electrician out to a fault, and then refuses access to those areas necessary to find and repair the fault, then the client is responsible in law for the fault and any problems that may arise from it. If the client calls out the electrician and employs him to repair the fault, then the electrician becomes the authorised person ( duty holder) This means he/she (the electrician) is responsible for those parts of the installation under his control, and also those areas of the installation affected by his working.
Care must be made when looking at any fault in an installation
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Equipment
The cost of replacement becomes a major factor when thinking about repairing an item of equipment
Manufacturing processes today mean it is often more cost efficient to replace rather than repair.
The labour cost of employing an electrician are quite often higher than the replacement value.
Smaller motors are usually cheaper to replace than the cost of rewinding them.
The availability of like for like is sometimes a problem with older equipment, replacement may not be an option.
Repairing equipment is situ, might be easy but this has to be weighed against loss of production time.
Many maintenance departments keep duplicate stock to minimised disruption.
The same legal responsibilities apply to equipment as for whole installations. This has made PAT testing more common. End of session 6
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