Question 1

The documents which should be completed after the addition of a ring final circuit to an existing installation are
A) Minor works certificate and a condition report
B) Schedule of tests and an electrical installation report
C) Electrical installation report, Schedule of test results and a schedule of inspections
D) Electrical installation condition report, Condition report schedule of inspections and a schedule of test results

Accepted Answer

Adding a ring final circuit to an existing installation requires documentation that verifies the safety and compliance of the new work with existing standards. This includes an Electrical Installation Report to detail the work done, a Schedule of Test Results to show that the new circuit meets electrical safety standards, and a Schedule of Inspections to document the inspections carried out to ensure the installation's compliance with regulations.

Question 2

The statutory document which relates to the DNO
A) Electricity at work regulations
B) Electrical supply act
C) Health and safety at work act
D) Electrical safety, quality and continuity regulations

Accepted Answer

The Electrical Safety, Quality and Continuity Regulations (ESQCR) apply specifically to the Distribution Network Operators (DNOs) in the UK, and are designed to ensure safe and reliable electricity distribution. They cover areas such as safety provisions, quality of the electrical supply, and the continuity of the supply network. The other options (A, B, C) are important regulations but not directly related to DNOs.

Question 3

Who should be consulted with regards to the extent and limitations when carrying out a periodic inspection which has been requested on a licensed property?
A) The client and the DNO
B) The DNO and the insurance company
C) The insurance company and the fire brigade
D) The local licensing authority and the landlord

Accepted Answer

The local licensing authority and the landlord should be consulted regarding the extent and limitations of a periodic inspection requested on a licensed property as they have the legal responsibility for ensuring compliance with licensing regulations and maintaining the safety of the property. The DNO and insurance company may have some input, but they are not directly responsible for the licensing and safety of the property. The fire brigade may be consulted for specific safety concerns, but they would not have the overall responsibility for the property's licensing requirements.

Question 4

When and where should the extent and limitations of a periodic inspection be recorded?
A) Before starting work and on an electrical installation condition report
B) On completion of the work and on an electrical installation condition report
C) Before starting work and on an electrical installation certificate
D) Before starting work and on a periodic inspection report

Accepted Answer

The extent and limitations of a periodic inspection should be recorded before starting work and documented on an electrical installation condition report to ensure clarity and agreement on the scope of the inspection.

Question 5

List in the correct sequence the first three tests to be carried out on a new 3 phase industrial cooker circuit
A) Continuity of cpc, insulation resistance an polarity
B) Polarity, continuity of cpc and insulation resistance
C) Visual inspection, earth fault loop and continuity of cpc
D) Polarity, earth fault loop impedance and insulation resistance

Accepted Answer

The correct sequence for testing a new electrical circuit is: 1) Continuity of cpc (circuit protective conductor), 2) Insulation resistance, and 3) Polarity. This ensures the circuit is safe and correctly wired before being energized.

Question 6

What would be the most appropriate way to verify the continuity of a 45m long 10mm2 protective bonding conductor
A) Use method 2
B) Visual inspection
C) Use method 1
D) R1 + R2 method

Accepted Answer

The answer of What would be the most appropriate way...

Question 7

The maximum length of 10mm2 cable which has a resistance of 1.83mO per mtr which can be used for main protective bonding is
A) 20mâ„¦
B) 27mâ„¦
C) 29mâ„¦
D) 25mâ„¦

Accepted Answer

The maximum length can be calculated by dividing the maximum resistance allowed for main protective bonding (which is typically 0.05 ohms or 50 milliohms) by the resistance per meter of the cable. Given the resistance per meter is 1.83 milliohms (mΩ), the calculation is 50mΩ / 1.83mΩ/m = 27.32m. Since options are rounded, 27m (option B) is the closest correct answer.

Question 8

When carrying out the 1st stage of a ring final circuit test the most likely reason for the cpc resistance value being higher than the live conductors is
A) The csa is greater
B) The conductor is longer
C) The csa is smaller
D) The conductor is shorter

Accepted Answer

The most likely reason for the cpc resistance value being higher than the live conductors is that the csa (cross-sectional area) of the cpc is smaller than the live conductors. This would result in a higher resistance value.

Question 9

Stage one of a ring final circuit test gives the values of the live conductors as 0.6O and the cpc as 0.99O. The tests carried out at stage 2 and stage 3 should provide the following values at each socket on the ring
A) 0.3â„¦ and 0.397â„¦
B) 0.6â„¦ and 0.397â„¦
C) 0.397â„¦ and 0.8â„¦
D) 0.3â„¦ and 0.3â„¦

Accepted Answer

Stage 2 and stage 3 tests in a ring final circuit test are designed to verify the continuity and the correct wiring of the circuit. The values obtained in stage one (0.6Ω for live conductors and 0.99Ω for cpc) should be halved when measured at any socket on the ring because the measurements are taken across the ring, effectively halving the resistance due to the parallel paths. Therefore, the expected values at each socket would be 0.3Ω for the live conductors (half of 0.6Ω) and approximately 0.495Ω for the cpc (half of 0.99Ω), but since the choice closest to this value for cpc is 0.397Ω, it indicates a possible typo or simplification for the purpose of the question.

Question 10

The effect on the measured value of insulation resistance and conductor resistance when the length of the conductor is increased is
A) Insulation resistance will reduce and the conductor resistance will increase
B) Insulation resistance will reduce and the conductor resistance will reduce
C) Insulation resistance will increase and the conductor resistance will increase
D) Insulation resistance will not change and the conductor resistance will increase

Accepted Answer

The resistance of a conductor is directly proportional to its length. Therefore, as the length of the conductor increases, the conductor resistance will increase. The insulation resistance is not affected by the length of the conductor.

Question 11

The measured value of insulation resistance when a circuit is tested together with ten other circuits will
A) Not change
B) Increase
C) Reduce
D) Be ten times greater

Accepted Answer

The presence of other circuits can cause a leakage current through the insulation, resulting in a reduction in insulation resistance.

Question 12

An insulation resistance test carried out on a circuit containing a surge protection device, the test voltage used and minimum insulation resistance value is
A) 500v d.c. and 1 MO
B) 250v d.c. and 1 MO
C) 250v d.c. and 0.5MO
D) 250v d.c. and 1 mO

Accepted Answer

According to industry standards, the recommended test voltage for an insulation resistance test on a circuit containing surge protection devices is 250v d.c. The minimum acceptable insulation resistance value is 1 MO. Therefore, the correct choice is B, which matches both the test voltage and minimum insulation resistance value.

Question 13

One effect of a circuit protective device connected in to the neutral conductor only would be
A) The device will operate on a neutral to earth fault
B) The device will not operate on overload
C) The circuit will remain live after an overload
D) The device will not operate during a short circuit

Accepted Answer

The answer of One effect of a circuit protective device...

Question 14

Two special locations which are divided into zones are
A) A restrictive conductive location and a room containing a bath or shower
B) A Sauna and a Construction site
C) A Marina and a Caravan site
D) A Sauna and a room containing a bath or shower

Accepted Answer

Both a sauna and a room containing a bath or shower require special attention to electrical safety, as they involve exposure to moisture. Therefore, these two locations are divided into zones according to the level of electrical risk, with specific electrical requirements for each zone.

Question 15

The recommended IP rating for equipment installed in Zone 1 of a Bathroom is
A) IPX4
B) IP4X
C) IPXXD
D) IP5X

Accepted Answer

Equipment installed in Zone 1 of a bathroom should have a minimum IP rating of IPX4, which means it is protected against water splashing from any direction. It provides adequate protection against water splashes from basin taps, showers, and other fittings within a typical bathroom environment.

Question 16

Electrical equipment installed in a wet room which is cleaned by the use of a hose should have a minimum IP rating of
A) IP5X
B) IPX5
C) IPX4
D) IPX8

Accepted Answer

IPX5 rating ensures that the electrical equipment is protected against water jets from any direction, which is suitable for environments cleaned with a hose.

Question 17

Using the circuit data provided
Ze 0.32O
Conductor resistance 7.41mO/m
Circuit length 38 m
The measured earth fault loop impedance for the circuit would be
A) 0.563â„¦
B) 0.883â„¦
C) 0.442â„¦
D) 0.281â„¦

Accepted Answer

The earth fault loop impedance (Zs) is calculated by adding the external earth impedance (Ze) and the impedance of the circuit conductors. The conductor impedance is the resistance per meter multiplied by the circuit length. Thus, Zs = Ze + (conductor resistance * circuit length) = 0.32 + (0.00741 * 38) = 0.883Ω.

Question 18

What is the maximum percentage voltage drop permitted for a 230 volt lighting circuit
A) 6.9%
B) 11.9%
C) 5%
D) 3%

Accepted Answer

The answer of What is the maximum percentage voltage drop...

Question 19

The maximum volt drop permitted for a 230v ring circuit is
A) 6.9v
B) 11.5v
C) 5v
D) 3v

Accepted Answer

The maximum volt drop permitted for a 230v ring circuit is 5% of 230v, which is 11.5v. Therefore, option B is the correct choice.

Question 20

The type of inspection and test most likely to require verification of volt drop is
A) Initial verification
B) Installation where no documentation is available
C) Periodic inspection and test
D) Industrial

Accepted Answer

Periodic inspection and test includes checking the condition of cables and connections. Verification of volt drop is required to ensure that there is no excessive voltage drop across the cable length. This helps in identifying any potential safety hazards and ensures that the electrical installation is safe and compliant with regulations.

Quiz 5: Earth Electrode Testing

The documents which should be completed after the addition of a ring final circuit to an existing installation are

The statutory document which relates to the DNO

Who should be consulted with regards to the extent and limitations when carrying out a periodic inspection which has been requested on a licensed property?

When and where should the extent and limitations of a periodic inspection be recorded?

List in the correct sequence the first three tests to be carried out on a new 3 phase industrial cooker circuit

What would be the most appropriate way to verify the continuity of a 45m long 10mm2 protective bonding conductor

The maximum length of 10mm2 cable which has a resistance of 1.83mO per mtr which can be used for main protective bonding is

When carrying out the 1st stage of a ring final circuit test the most likely reason for the cpc resistance value being higher than the live conductors is

Stage one of a ring final circuit test gives the values of the live conductors as 0.6O and the cpc as 0.99O. The tests carried out at stage 2 and stage 3 should provide the following values at each socket on the ring

The effect on the measured value of insulation resistance and conductor resistance when the length of the conductor is increased is

The measured value of insulation resistance when a circuit is tested together with ten other circuits will

An insulation resistance test carried out on a circuit containing a surge protection device, the test voltage used and minimum insulation resistance value is

One effect of a circuit protective device connected in to the neutral conductor only would be

Two special locations which are divided into zones are

The recommended IP rating for equipment installed in Zone 1 of a Bathroom is

Electrical equipment installed in a wet room which is cleaned by the use of a hose should have a minimum IP rating of

Using the circuit data provided Ze 0.32O Conductor resistance 7.41mO/m Circuit length 38 m The measured earth fault loop impedance for the circuit would be

What is the maximum percentage voltage drop permitted for a 230 volt lighting circuit

The maximum volt drop permitted for a 230v ring circuit is

The type of inspection and test most likely to require verification of volt drop is