Worksheets12. Inspection & Testing
Total questions: 45
Worksheet time: 23mins
According to the Electricity at Work Regulations 1989, the person who may carry out an unsupervised inspection of electrical systems will have
A good understanding of the Building Regulations
An IET Wiring Regulations qualification
Appropriate knowledge and experience of inspection work (Note: definition of a Competent person)
Five years’ experience of a range of electrical installation work
A person carrying out safe isolation is required to
Only use a multimeter
Assume labelling is correct
Correctly identify the circuit
Only isolate at the mains
Proving units are used to ensure that
Insulation resistance testers function correctly
Multimeters function correctly
Low resistance ohmmeters function correctly
Approved voltage indicators function correctly
For what reason might isolation of a circuit need to occur on a weekend?
Avoids the need to notify a loss of supply
So that apprentices can learn the trade
Need to maintain overtime work
Need to maintain productivity in a factory
A new build project needs the supply to a socket outlet to be energised from a distribution board (DB) that has yet to be completed. Before energising the socket outlet the inspector should
Test the circuit only
Install the DB cover only
Test the circuit and install the DB cover
Inspect the circuit and install the DB cover
Which document gives a tester the authority to open a live distribution board for testing purposes?
Permit to work
Risk assessment
Method statement
Schedule of inspections
Which of these is not a purpose of initial verification as described by BS7671?
The installation is fit for continued use
The avoid danger to persons and livestock
The requirements of the regulations have been met
To avoid damage to property
When should inspection and testing be carried out?
After the installation is energised
On completion of the installation only
During erection of the installation only
During erection and on completion of the installation
Which of these documents is statutory?
The Electricity at Work Regulations 1989
IET Wiring Regulations
IET Guidance Note 3
NICEIC Guide to Inspecting and Testing
To correctly assess whether a new installation complies with the regulations, certain information should be made available to the inspector. This requirement does not include:
Installation maintainability
Type of system earthing
Nature of supply
Maximum demand
During an inspection, which checks are to prevent mutual detrimental influence between electrical and non-electrical installations?
Checking functional switches are accessible
Making sure that all bonding is in place
Checking that steam or heat will not damage the electrical installation
Making sure connections are correctly labelled
Which diagram illustrates checking or nulling the test leads before starting a continuity test?
The first diagram
The second diagram
The third diagram
The fourth diagram
A radial power circuit has been installed without any spurs, and is protected by a 32A type B circuit breaker. What is the minimum cross-sectional area (c.s.a) of the live conductors?
2.5mm²
4mm²
6mm²
1.5mm²
When inspecting a bathroom, there was a space under the bath which was accessible without the use of a tool. This space is regarded as being:
Within zone 1
Within zone 0
Outside of the prescribed zones
Within zone 2
What is the minimum IP rating for correctly rated and protected current, using equipment in zone 1 of a room containing a fixed bath if there are no water jets?
IP 5X
IP X5
IP X4
IP 4X
An alternative method for this test that uses a long wander lead is often referred to as continuity test method. What is the number associated with this method?
3
4
1
2
What is the correct scale for the measurement of insulation resistance?
ms
kA
MΩ
Ω
Which diagram shows inadequate basic protection?
(a)
(b)
(c)
(d)
When conducting testing of a premises which has been in service for 15 years, what is the appropriate action to take if a reading fails the test but there is no imminent danger present?
Pass the circuit, record a good reading as there is no imminent danger and continue with the rest of the testing
Record the result, issue the relevant classification code and inform the client
Record the value, issue a code 1 and lock off the particular circuit breaker
Record the value, no code needed but advise the client that work will need to be completed at the next test interval
The sequence of testing as shown in GN3 is carried out during initial verification of new build because:
This is the sequence laid down by the Electricity at Work Regulations and cannot be changed
The result of a previous test may influence the next test
GN3 is a statutory document and must be followed in that order
This is the sequence laid down by the Building regulations and cannot be changed
The reason to carry out the continuity of protective conductors’ test is to ensure that the conductor:
Is broken
Has no resistance
Is not broken and is of low resistance
Has a resistance
A long return lead is used to test the continuity of the protective conductor. Meter nulling is not available. Which calculation must be performed to find the resistance of the protective conductor?
Multiply the resistance of the long lead with the reading taken at the test point
Add the resistance of the long lead to the reading taken at the test point
Subtract the resistance of the long lead from the reading taken at the test point
Divide the resistance of the long lead by the reading taken at the test point
A ring final circuit test is carried out. During step 1 of the test the resistance of the end to end loops at the consumer unit are r1: 0.8Ω, r2: 1Ω. If the circuit has no spurs, what is the expected value of R1 + R2?
0.3Ω
0.45Ω
0.9Ω
0.6Ω
Which will decrease the resistance of a copper conductor?
operate the conductor at a lower temperature (Note: Carbon brushes in motors has the opposite effect)
replace the conductor with one of smaller csa
increase the cable length
add another cable in series
Testing for insulation resistance may involve disconnecting or removing which of the following?
Joint boxes
Switches
Electronic devices
MCB’s
What is the insulation resistance test voltage for a single-phase circuit?
500V d.c
500V a.c
250V a.c
250V d.c
When a cable’s length is reduced, the effect on the insulation resistance will be to:
Stay the same
Reduce
Increase
Fluctuate
Why is it necessary to check the polarity of the supply to an installation?
The supply may have swapped live conductors (Note: Live meaning line and neutral)
The installation wiring may be incorrectly connected
The supply earth may be incorrect
The supply voltage may have an incorrect value
Which instrument is used to confirm the polarity of the incoming supply?
An earth fault loop impedance tester
A low resistance ohm meter
An approved voltage indicator
An insulation resistance meter
The three results from an earth electrode tester on a TT system were 100Ω, 110Ω and 90Ω. What value is recorded on the schedule of test results?
90Ω
100Ω
200Ω
110Ω
As part of a TN-C-S earthing system the supply uses
A separate neutral and earth cable
Isolation of the neutral from earth
The earth as part of the earth fault loop
A combined neutral and earth cable
The value of Ze was enquired from the DNO and a value of 0.35Ω was given. The earthing arrangement is most likely to be
TT
TN-C-S
IT
TN-S
If Ze is 0.35Ω and (R1 + R2) is 0.25Ω, the value of Zs will be
0.35Ω
0.25Ω
0.6Ω
0.0875Ω
The measured value of prospective fault current for a single-phase installation can be checked by
Looking in BS 7671 IET Wiring Regulations
Voltage divided by the demand load
Voltage divided by Ze
Looking in BS 7671 On Site Guide
What is the minimum permitted value to be found on a protective device at the origin of a 230V single phase circuit where Ze is 0.12Ω?
6000
1500
3000
10000
An RCD is used for additional protection. When tested it will be subject to a maximum test current of at least
300mA
150mA
100mA
30mA
The phase sequence should be checked at
Each multiphase distribution circuit only
Each multiphase final circuit only
The origin and each multiphase distribution and multiphase final circuit
The origin only
A check for phase sequence at the main intake to a three-phase installation indicated a result of L1, L3, L2. The correct orientation at each subsequence distribution board is
L2, L1, L3
L2, L3, L1
L3, L2, L1
L1, L3, L2
An RCD should have its test button checked to show that the
Device will operate at a set current
Device will operate
Device will operate at a set current and time
Device will operate within a set time
On completion of an electrical installation and in addition to an Electrical Installation Certificate. The inspector should issue the person ordering the work with a
Building Control Certificate and a schedule of inspections
Schedule of test results and a schedule of inspection
Schedule of test results only
Schedule of inspections only
Which certificate serves the purpose of confirming that a new circuit has been designed, constructed and inspected and tested to conform to BS 7671?
Electrical Installation Certificate
Electrical Installation Condition Report
Minor Electrical Installation Works Certificate
Landlords safety certificate
On which document is the nature of supply parameters recorded?
Electrical Installation Certificate
Schedule of Inspections
Minor Electrical Installation Work Certificate
Schedule of test results
After initial verification of a new build domestic house, under normal usage, what would be the expected time interval to the first inspection and test?
20 years
10 years
15 years
5 years
How long should the documentation be kept after an initial verification?
20 years
For the working lifetime of the building
Until the next inspection
Until there is an alteration to the building
Which is not allowed to be used as a protective conductor?
A metal conduit
Flexible conduit
A conductor within a cable
A single core cable
