WorksheetsInspection, Testing and Verification — C&G 2392 Paper 1
Total questions: 15
Worksheet time: 8mins
A number of cables are tested for insulation resistance. The highest individual value is 200Ω and the lowest is 20M ohms. The measured value, when the cables are all connected in parallel, will be:
greater than 200M ohms
200M ohms
less than 20M ohms
the sum of the individual values
The test voltage and minimum insulation resistance test values for an installation forming part of a 230 V single-phase, TN-C-S system are:
250 V and 0.5M ohms
250 V and 1.0M ohms
500 V and 0.5M ohms
500 V and 1.0M ohms
A 230 V single-phase circuit supplies a light which is controlled by a passive infrared sensor. Special care must be taken before insulation resistance testing is carried out because the test may:
cause the circuit breaker to trip
operate the sensor and damage the light
permanently damage the sensor
giving a false reading
In a room containing a shower, the area inside the shower tray is referred to as Zone:
0
1
2
3
A circuit is to be installed to supply equipment mounted in an exposed, high-level location outdoors. To confirm the equipment is suitable for the environmental conditions reference would be made to the degree of protection offered in accordance with the:
IK code
IP code
Electricity at Work Regulations
HSE Guidance Note GS 38
The correct connection of a single pole isolator must be confirmed using a test for:
continuity
polarity
insulation resistance
loop impedance
A new electrical installation forming part of a TT system is to be tested as part of the initial verification process. The first test to be carried out once polarity has been confirmed is:
external earth loop impedance
prospective short circuit current
earth electrode resistance
operation of RCDs
At the intake position for a domestic electrical installation the earthing conductor is connected to the lead sheath of the supply cable. The type of system is:
TT
TN-C-S
TN-C
TN-S
A test of earth fault loop impedance is carried out on a socket outlet circuit and the maximum value given in the BS 7671 tables is 2.3 ohms. What is the maximum measured value which would be acceptable?
2.80 ohms
2.30 ohms
1.84 ohms
1.65 ohms
The earth fault loop impedance of a circuit cannot be confirmed by direct measurement as no energy meter has been installed for the installation. One method of determining earth fault loop impedance is by calculation using the formula:
Zs = Ze + [R1 + R2]
Ze = Zs + [R1 + R2]
Zs = Ze − [R1 + R2]
R1 + R2 = Zs − Ze
A test is being carried out as part of the initial verification of a new installation and the test instrument displays a value of 0.9kA. The test being carried out is to determine:
earth fault loop impedance
prospective fault current
RCD tripping times
continuity of protective conductors
Where two RCDs are connected in series the first RCD must incorporate:
an auto reset facility
overload protection
a time delay
an audible warning
A 10mA RCD has been installed to provide additional protection. When testing this RCD the maximum test current that should be applied is:
10mA
30mA
40mA
50mA
The protective device at the origin of a new electrical installation is a BS 1361 Type II B. The installer must confirm that this device is able to disconnect the prospective fault current:
in the required time
without operation
without damage
in prescribed conditions
The maximum voltage drop permitted for a low voltage installation supplied from a public supply is 3% for lighting circuits. For all other circuits the figure is:
3%
4%
5%
6%
