Installation, Maintenance and Customer Service
Installation, Maintenance and Customer Service
This domain tests site survey, load and cable selection, protective devices, equipment mounting, preventive maintenance, documentation and professional customer handling.
Core rules
- Survey the site for supply capacity, earthing, ventilation, cable route, mounting strength and service access.
- Calculate current from power and voltage, then select cable and protective devices with margin. Account for continuous loads and derating.
- Use an RCCB for personal protection and an MCB for overcurrent; verify polarity and earth before energising.
- Wall-mount heavy equipment into studs or suitable anchors, not drywall alone. Leave ventilation clearance and a drip loop on outdoor cables.
- Record serial numbers, readings, replaced parts, warranty status and customer approval.
- Explain the fault and the repair in plain language; give a realistic time and cost estimate; do not promise an outcome you cannot verify.
- Preventive maintenance includes cleaning vents, checking connections, testing protection and inspecting cables.
Worked example
A 1500 W geyser is to be installed on a 230 V supply. Current = 1500/230 = 6.5 A. A 2.5 mm² copper circuit is adequate for this current in a short run, protected by a 16 A MCB and a 30 mA RCCB, with a correctly sized earth. Confirm the isolator is accessible and the cable route avoids heat. After installation, test insulation resistance, polarity and earth continuity, then record the readings and explain the isolation switch to the customer.
Traps
Selecting cable by habit without calculating load; omitting the RCCB; sealing ventilation openings; fixing a heavy bracket only into plasterboard; failing to record serial numbers and customer consent.