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WorksheetsFault Finding
Total questions: 14
Worksheet time: 28mins
An operative carrying out fault diagnosis would not need to be familiar with:
supply earthing system
schedule of test results
repair cost
voltage present
Which of the following would not be required in a fault finding sequence:
time repair will take
safe isolation
testing
analysis of results
A continuity test as part of fault diagnosis would be carried out with which instrument:
earth-fault loop impedance tester
high resistance ohmmeter
low resistance ohmmeter
RCD tester
A loose termination could cause the following
short circuit between live conductors
overcurrent
arcing
operation of the protective device
Which of the following problems would not be classed as a transient fault
overload
lightning
heavy current switching
earth-fault voltages
The guidance for test leads used on instruments is contained in
BS 7671
EAWR
HASAWA
GS38
Which of the following documents is of least use when diagnosing faults?
Schedule of test results
Electrical Installation Certificate
Installation specification
Maintenance record
Which dead test would be carried out during intial fault diagnosis
RCD test
insulation resistance
functional
earth-fault loop impedance
On inspection of terminations at a motor, you observe conductor insulation has melted and discolouring of the terminal metal the most likely cause would be:
overcurrent
loose connection
open circuit
earth fault
Whilst fault finding you check and discover the BS 3036 fuse protecting the circuit has ruptured with globules of copper spattered over the holder together with black carbon powder. The most likely fault would be:
short circuit
open circuit
loose termination
broken conductor
Whilst fault finding, you check and discover the BS 3036 fuse protecting the circuit has melted in the middle only. The most likely fault would be:
open circuit
short circuit
loose termination
overload
A result of >100Ω on a continuity test would indicate what type of fault:
none
an insulation failure
open circuit
short circuit
An RCD would protect against the following fault:
open circuit
overcurrent
short circuit between live conductors
short circuit between live conductors and earth
Antistatic precautions would not usually be considered in the following installation type:
office block
chemical works
petrol filling station
flour mill
