Electrical Fault Finding 5

Which of the following measures can help prevent electric shock during maintenance work?

• Ensuring all employees wear the same uniform

• Using only tools that are in good condition

• Having a single person responsible for all safety checks

• Clearly marking all electrical panels and circuits

Instrument used for testing have met the requirements of

• BS 88

• BS 7671

• BS 3036

• BS EN 61010

Answer explanation

The instrument used for testing must meet the requirements of BS EN 61010.

An electrician discovers a tripped circuit breaker in a factory's control panel and there are no immediate replacements available. The safest immediate action to take is to

• Reset the circuit breaker and continue working

• Replace the circuit breaker with a higher rating one

• Consult the maintenance supervisor for further instructions

• Bypass the circuit breaker temporarily

According to HSE Guidance Note GS38, what is a requirement for test probes?

• Must have an exposed metal tip not exceeding 5mm

• Should be equipped with finger guards to prevent accidental contact

• Need to be fitted with a 5A fuse

• Must be color-coded

When should maintenance reports and records by fully completed for any repair work?

• Within 3 months

• When a repair is finished

• Halfway through the job

• Within 1 month

An electrician needs to perform maintenance on the electrical system of a small store. What should the store owner do to ensure customer safety during this period?

• Provide flashlights to customers

• Limit the number of customers entering the store

• Temporarily close the store until maintenance is complete

• Have staff guide customers through the store

Following the repair of an electrical fault and on completion of testing, a copy of the report or certificate should be given to the

• Clerk of works

• Client

• Manufacturer of the fault item

• Building inspector

An engineer is replacing some wiring and damaged overhead trunking at a small furniture factory and production of one section has had to be stopped for the work to be done. Who does the engineer need to keep informed about the progress of the repair and why?

• The production manager, to ensure that the most appropriate decisions can be made

• The electrical wholesaler, in case any materials are needed at short notice

• The factory owner, so that a new profit forecast can be made

• The Health and Safety representative at the factory, because work is being carried out overhead

An electrician is called to a problem on a 3-phase motor. The operator reports there was a louder than usual humming from the motor shaft which appeared to vibrate rather than rotate. What is the likely cause of the problem?

• The overload has tripped

• The cpc has become high resistance

• Two of the motor phases are short circuited

• One of the supply fuses has blown

Where earth fault impedance values cannot be satisfied, one solution is to fit an

• Earth electrode

• MCB

• RCD

• Overload relay

Answer explanation

One solution to satisfy earth fault impedance values is to fit an RCD (Residual Current Device). It helps detect and disconnect faulty circuits to prevent electric shocks.