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Worksheets5357 Electrical
Total questions: 20
Worksheet time: 20mins
The term given to the person responsible for an electrical system is the:
Competent person
Electrician
Duty holder
Company manager
Regional electricity companies quote a maximum likely value of external loop impedance (outside the consumer's installation) for a TN-S system as:
0.35 ohm
0.8 ohm
21 ohm
200 ohm
EAWR states that working live is acceptable unless:
Suitable tools are used
Suitable PPE is worn
It is reasonable in all circumstances for it to be dead
An engineer gives you permission
Overloaded windings on a 3 phase motor may be identified in the first instance by using which sense:
Sight
Smell
Touch
Taste
Which of the following earthing systems has the path for earth leakage currents via the earth itself:
TN-S
TNC-S
TN-C
TT
Which of the following is the correct voltage for carrying out an insulation resistance test on a 400V three-phase circuit terminated at an isolator?
250 V
400 V
500 V
1000 V
A continuity test is to be carried out and the instrument has been confirmed as being in calibration and undamaged, Which of the following is the remaining check that needs to be carried out to confirm the instrument is suitable to use?
It is set to 230 V a.c
The battery is in a good condition
The leads comply with GS 38
It is set to read high values of resistance
Which of the following is the minimum short circuit test current for a low resistance ohmmeter?
50 mA
100 mA
200 mA
300 mA
Test instruments should be calibrated in accordance with the manufacturers instructions to ensure accurate test results. In addition to calibration which of the following should be carried out and recorded?
Regular conformation of the instrument`s compliance with BS 7671
Extension of the instrument warranty period
Regular instrument accuracy checks
Closed circuit voltage checks
Which of the following is the maximum voltage above which test leads must comply with the requirements of GS 38?
25 V a.c.
25 V d.c.
50 V a.c.
50 V d.c.
During initial verification of a TN system the installation earth conductor was recorded as 16mm2. The minimum size of main bonding conductor should be:
4mm2
6 mm2
10 mm2
16 mm2
Which of the following is not permitted for use as an earth electrode:
Underground structural metalwork
Metal water mains pipes
Lead sheaths of cables
Earth plates
Which one of the following does not need to be checked for compliance during the visual inspection of an installation:
presence of fire barriers
correct connection of the supply authority's fuse
routing of cables in safe zones
connection of single pole devices in line conductors only
End-to-end resistance checks would be carried out on a:
radial circuit
lighting circuit
ring final circuit
fused connection unit
The purpose of the test button of a residual current device is to check the
Earth fault loop impedance
Continuity of the earthing conductor
Earth electrode resistance
Mechanical operation of the rcd
OSG gives the maximum stable value of Ze for a TT installation as:
1660 ohms
600 ohms
200 ohms
100 ohms
Which type of earthing system relies on a separately supplied earth, usually the sheathing on the cable:
TT
TN-C-S
IT
TNS
Which of the following would not be one of the human senses to use during the initial verification of an addition to a lighting circuit:
Sight
Hearing
Taste
Touch
On a standard TT installation, the result of the resistance of the earth electrode and the rated RCD residual operating current should not exceed:
25v
50v
110v
400v
Which of the following protection devices is unlikely to be suited for short circuit currents in the region of 6kA:
BS 3036 semi-enclosed fuse
BS 88-3 cartridge fuse
BS 88-2 general purpose fuse
BS EN 60898 circuit breaker
