2391 questions sample 5

Sample questions
1) Indicate three main items for which you would require relevant information about
in order to undertake an initial inspection on a new installation.
2) State relevant documentation that relate to the inspection and test of a system
Name one statutory and two non statutory.
3) An Electrical Installation Certificate and a Periodic Inspection Report should be
accompanied by two other documents what are they?
4) State three areas of inspection you would check when carrying out a periodic
inspection.

5) State three human senses used when carrying out a Periodic Inspection Report
6) List the instruments which provided the measurements 20 Megohms, 8KA and
22mS.
7) Insulation resistance testing requires different test voltages for certain circuits,
identify what circuits require the following voltages 250v, 500v and 1000v.
8) State the first three tests that should be taken during the initial verification of a
new installation.
9) The test for continuity of the CPC in a radial circuit with one socket requires a
link and a Milli-ohmmeter state: were link is connected, where the meter is
connected, what the meter reading represents.

10) State three different protective conductors that need to be connected to the
main earth terminal.
11) The following results were obtained during the initial test on a healthy ring
circuit.
P1 > P2 = 0.8 ohms
N1 > N2 = 0.8 ohms
CPC1 > CPC2 = 0.8 ohms
What readings would you expect after cross connection
Between Line and neutral at each socket?
Between Line and CPC at each socket?
What does the Line and CPC represent? The following results
12) State the effect on, Conductor resistance when cable length increases.
Conductor resistance when CSA increases. Insulation resistance when cable length
increases.
13) State three precautions to be taken before an insulation resistance test on a
circuit.

14) An enclosure has been fabricated on site state the minimum IP rating, it is not
affected by liquids.
15) State the protection offered by the following IP ratings IP4X, IPX8, IPXXB.
16) State three reasons for conducting polarity checks on a circuit.
17) ID earthing system that is connected with overhead cables, a multi core supply
cable with separate earth and neutral, supply in which earth and neutral are
performed in one conductor.
18) State three location were there are additional requirements for an electrical
installation
19) From the formula Zs = Ze+(R 1 + R 2 ) x 1.2 x L state what is Ze, R2 and 1.2
1000

20) State three functional test to be carried out on an installation.
21) Carry out initial verification of the installation.
a. what information/documentation is required
b. were should it be found
c. what particular uncommon details should be recorded on this installation.
d. what consideration should be given to the existing installation from which the new one
is fed.

22) List five areas of inspection that should be undertook before testing
23) The electronic door/sensor/motor is wired on its own radial circuit.
List ALL the component parts of the earth fault current loop path associated with
this circuit in the event of a fault to earth
If the maximum value of Earth Loop Impedance for this circuit is 2.4Ω and an earth
fault causes a current of 120A show by calculation if this value will disconnect the
circuit in the required time.
In questions like this please consider a diagram to help explain to the examiner and
to help you recognise any areas you may have missed.

24) The test results shown below were obtained from a ring final circuit continuity
test. State whether the readings for each socket are satisfactory or not satisfactory
giving reasons for those readings deemed to be unsatisfactory. The line, neutral
and the circuit protective conductors have loop test results of 0.5Ω
Socket Line to Neutral Line to CPC
A 0.25 0.26
B NO READING 0.25
C 0.35 0.24
D 0.24 NO READING
E 0.26 0.26
25) Describe in detail how you would carry out an insulation resistance test on this
installation.
26) The test result indicates an overall value of 1.75 MΩ. State with reasons, what
actions if any should be taken.
27) A loop impedance test on the lighting circuit cannot be carried out because the
6A MCB is tripping under the test voltage, why?
28) How can this be overcome?
29) State THREE circumstances that would require a periodic inspection and test to
be carried out on an installation.

30) There are various documents that are relevant to the Inspection and Testing of
an installation. State a) one statutory item of documentation b) two non-statutory
items of documentation.
31) A Electrical Installation Certificate should be accompanied by signed
documentation regarding thee stages of an installation. Identify
TW0 of these stages
The status of the person signing.
32) List THREE areas other than wear and tear and ageing that should be
considered when carrying out a periodic inspection and test of an insulation.
33) BS 7671 gives a list of 18 items to be checked, where relevant, during an initial
inspection. List THREE of these.
34) State the electrical units in which EACH of the following test results would be
expressed.

35) Identify the type of circuit that would require the following applied voltages
when conducting an insulation resistance test.
a) 250v
b) 500v
c 1000v
36) List the first three tests that should be carried out during periodic inspection
and test of an installation.
37) Name the protective conductors that connect together the following.
a) An electrically heated towel rail and exposed metal pipework in a bathroom.
b) The earthing terminal of a socket outlet and the main earthing terminal.
c) Mains Gas and Water services to the main earthing terminal.
38) State the essential action to be taken before disconnecting a main protective
bonding conductor for test purposes during a periodic inspection and test and
danger that would arise if this action is not taken.
39) State the
a) Equipment required to conduct a ring final circuit continuity test b) other test that
is automatically completed when the test in a) is carried out c) significance of the
reading obtained between Line conductor and CPC at each socket outlet.

40 In the test required to verify the electrical separation of a SELV circuit
a) instrument to be used
b) test voltage to be applied.
41) With regards to polarity testing of an installation, state a) the instrument to be
used b) in which conductor all single pole devices should be connected c) to which
part of an Edison screw landholder the neutral conductor should be connected.

42) The diagram below shows the layout of the electrical installation in a detached
garage. The owners have, for some time been using it for a business venture
repairing lawnmowers, electric and petrol driven. Heating is provided by two 2 kW
convector heaters plugged in when needed. The three Way metal clad consumer
unit houses a double pole main switch and BS 1871 type 2 M.C.B.'s. All surface
wiring is multicore PVC. non-armoured cable clipped direct, and all socket outlets
(these have been raised from their original position to bench level) and lighting
switches are made from moulded plastic.
43) State the a) documentation and information it would be useful to have regarding
this installation b) action to be taken if such documentation is unavailable c)
documentation that will need to be completed for this inspection and test d) test
equipment needed.

44 ) State THREE general causes for concern regarding the use of this installation
that would be revealed during a visual inspection.
Briefly explain the reasons for EACH of the concerns listed and for each one
suggest a possible solution.
45) Why is it necessary to carry out a ring circuit continuity test in this garage
installation? Describe how the test in a) should be carried out. Indicate the
instrumentation to be used. Which of the test results would be recorded on the test
schedule?

46) State pre-test precaution before insulation resistance test undertook
47) Test voltage to be used
48) Individual circuits give readings of 80M ohm 60M ohm and 30M ohm what is
expected overall resistance. We need to consider that the circuits will be in parallel
with each other when connected to the supply.

49)An inspection is required of a change in builder owner ship. State the
Type of inspection required?
Documentation that will need to be completed?
50) State the three items of technical information that must be recorded on the
Schedule of Test Results, and relate to the incoming supply to the installation.
51) State with who should the extent and limitations of the inspection and test
should be agreed with?
52) Where should this be recorded?