Fault Finding Quiz

When preparing to work on a three-phase pillar drill, the number of tests required to prove isolation has been correctly completed is

• 3

• 9

• 10

• 12

Which of the following information is not required when diagnosing a fault?

• The Electrical Installation Certificate

• Events leading up to the fault

• Maintenance records

• The manufacturer’s instructions

A component has been identified as the cause of the fault but is not a stock item and requires ordering. What information should be given to the client?

• The supplier’s phone number to chase delivery

• The expected delivery/repair date

• The part number of the item ordered

• The way to bypass the faulty part, although safety will be impaired

An upgraded piece of equipment has been installed but repeatedly after 25 minutes of running, it trips out the circuit breaker. What is the most likely fault?

• A short circuit

• An overload

• An undervoltage

• A fault to earth

A customer has had new USB sockets fitted in the kitchen but can now hear a crackling noise. What is the most likely cause?

• An insulation resistance fault between neutral and earth

• An overvoltage outside the specification of the socket installed

• A loose connection

• Overloading the socket

The client informs you that the supply to a piece of equipment cannot be isolated as it will affect other machinery and you should work on it live. What should you do?

• Report the client to the HSE for suggesting an unsafe work procedure

• Make arrangements for isolating the supply at a mutually convenient time, such as out-of-hours

• Work live anyway

• Tell the client to find someone else to work on the equipment

An earth fault loop impedance test has been completed on a circuit and the reading is found to be 2.34Ω. GN3 tells you the maximum reading should be 1.8Ω. What is the implication of this?

• The equipment will not operate correctly

• The equipment will operate but the manufacturer’s warranty is now invalid

• The equipment will intermittently trip out

• The protective device will not operate quickly enough to comply with BS 7671 in the event of an earth fault

When lone working, others should be aware of your location, the time the activity is likely to take and what else?

• Ensure the bill for the client is correct for the time taken

• Enable the office to plan your next job knowing where you are and when you will finish

• Ensure your health and safety and check up on you

• Make sure you haven’t gone home

An item of equipment you have isolated has a notice stating also supplied from a UPS. UPS stands for

• untested portable supply

• uninterruptible power supply

• unified power supply

• underground power supply

An RCD protecting sockets in a computer suite intermittently operates when busy. What is a possible cause?

• A cumulative effect of earth leakage from multiple PCs

• An intermittent fault on one PC

• An overload when too many PCs are turned on

• An inrush current due to the power supplies in the PCs turning on together