Z
Zenn
Dear Friends
I have booked my 2391 exam on October 18th for third time and this is my last chance to pass it.
I have about five past exam papers and I want to post them here, My main problem is on Section B which is the hardest part.
I would really appreciate if you guys help me out to answer these questions and be ready for the exam. It will indeed be helpful for those who need to do this exam.
I will only posting Section (B) of each paper, If anyone need the Section (A) just ask me and I'm happy to take a photo and post them for you.
I have posted my answers in green, but for most of the question I don't know how to write down the answers, specially the ones with explanations.
DECEMBER 2011:
Section (B)
The owners of a small retail outlet have been advised to install security lighting to the rear of their property. The installation has been completed and is ready for inspection and testing. At the same time the owners require an inspection and test of the existing installation for their insurance company.
The installation forms part of 400/230 V, three-phase, TN-C-S system with a Ze of 0.1 (Ω) and a PFC of 8 (kA). The new circuit comprises single-core,copper conductors with thermoplastic insulation installed in a PVC conduit containment system. The luminaires contain sodium vapour discharge lamps and are controlled by a photo-cell mounted at the apex of the roof.
The existing installation comprises single-core, copper conductors with thermoplastic insulation contained within pvc conduit and trunking. The three phase and neutral distribution board is located at the origin of the installation at the front of the shop.
Circuit protection is by BS EN 60898 circuit breakers and BS EN 61009 RCBOs.
The circuit protective conductors are the same CSA as the live conductors for all the final circuits.
State :
1.
a) The documents that must be completed and passed to the client on completion of the electrical work.
Electrical Installation Certificate, Periodic inspection report, 2x Schedule of inspection, 2x Schedule of test report.
b) What must be agreed with the client before the inspection of the existing installation is carried out.
Extent and limitations of the inspection, such as access to the cables under the floors or disconnecting the system from supply.
c) Who is involved in the agreement process in (b) above.
inspector and client
d) Where the agreement in (b) above is recorded.
in the extent and limitations of the inspection section on PIR.
e) Two items of information related to DNO protective device which should be made available to the inspector.
Type of Protective device and Rated current.
____________________________________________________________________________________________
2.
a) Permission has been given and the installation isolated to allow the inspection at the origin to be undertaken. The cover has been removed from the distribution board.
Identify,
i) Three items within the DB which are to be inspected using the sense of touch stating what is being checked for in each case.
to checking that the circuit breakers functioning correctly, connection of all conductors to circuit breakers are sound and the earthing conductors are connected correctly.
ii) Two items within the DB which are to be inspected using the sense of sight stating what is being checked for in each case.
to checking that : there are no any crack or visible damaged to the DB or any part inside.
correct labelling and sequencing of all conductors.
b) State two items that would be checked during the inspection of the new lighting installation containment system stating what is being checked for in each case.
choosing the correct switches and conductor size.
c) State one other sense which may be used during the inspection of the existing installation.
sense of smell.
_________________________________________________________________________________________
3. A test of continuity of protective conductors is to be carried out on the new lighting circuit to determine the (R1 + R2) value before the circuit is connected to the DB.
Describe, in detail, How this test is to be carried out.
___________________________________________________________________________________________
4. Describe, in detail, How the external earth fault loop impedance for the installation is carried out by direct measurement.
___________________________________________________________________________________________________
5. The client has complained that the single phase motor for the hoist at the rear of the premises has been slow and getting hot. Due to the length of run it is suspected that
there may be a voltage drop problem.
a) Determine the voltage drop for the circuit if the combined measured resistance of the line and neutral conductors is 0.38 (Ω) and the load current of the motor is 30 (A).
b) Determine whether the voltage drop calculated in (a) above meets the requirements of BS 7671.
c) Explain one course of action that could be taken if the voltage drop is exceeded on this circuit, giving reasons for your choice.
______________________________________________________________________________________________________
6. Describe, with the aid of a fully labelled diagram, the earth fault loop impedance path for the new lighting circuit.
_______________________________________________________________________________________________
END
I will add more questions on here tomorrow.
I have booked my 2391 exam on October 18th for third time and this is my last chance to pass it.
I have about five past exam papers and I want to post them here, My main problem is on Section B which is the hardest part.
I would really appreciate if you guys help me out to answer these questions and be ready for the exam. It will indeed be helpful for those who need to do this exam.
I will only posting Section (B) of each paper, If anyone need the Section (A) just ask me and I'm happy to take a photo and post them for you.
I have posted my answers in green, but for most of the question I don't know how to write down the answers, specially the ones with explanations.
DECEMBER 2011:
Section (B)
The owners of a small retail outlet have been advised to install security lighting to the rear of their property. The installation has been completed and is ready for inspection and testing. At the same time the owners require an inspection and test of the existing installation for their insurance company.
The installation forms part of 400/230 V, three-phase, TN-C-S system with a Ze of 0.1 (Ω) and a PFC of 8 (kA). The new circuit comprises single-core,copper conductors with thermoplastic insulation installed in a PVC conduit containment system. The luminaires contain sodium vapour discharge lamps and are controlled by a photo-cell mounted at the apex of the roof.
The existing installation comprises single-core, copper conductors with thermoplastic insulation contained within pvc conduit and trunking. The three phase and neutral distribution board is located at the origin of the installation at the front of the shop.
Circuit protection is by BS EN 60898 circuit breakers and BS EN 61009 RCBOs.
The circuit protective conductors are the same CSA as the live conductors for all the final circuits.
State :
1.
a) The documents that must be completed and passed to the client on completion of the electrical work.
Electrical Installation Certificate, Periodic inspection report, 2x Schedule of inspection, 2x Schedule of test report.
b) What must be agreed with the client before the inspection of the existing installation is carried out.
Extent and limitations of the inspection, such as access to the cables under the floors or disconnecting the system from supply.
c) Who is involved in the agreement process in (b) above.
inspector and client
d) Where the agreement in (b) above is recorded.
in the extent and limitations of the inspection section on PIR.
e) Two items of information related to DNO protective device which should be made available to the inspector.
Type of Protective device and Rated current.
____________________________________________________________________________________________
2.
a) Permission has been given and the installation isolated to allow the inspection at the origin to be undertaken. The cover has been removed from the distribution board.
Identify,
i) Three items within the DB which are to be inspected using the sense of touch stating what is being checked for in each case.
to checking that the circuit breakers functioning correctly, connection of all conductors to circuit breakers are sound and the earthing conductors are connected correctly.
ii) Two items within the DB which are to be inspected using the sense of sight stating what is being checked for in each case.
to checking that : there are no any crack or visible damaged to the DB or any part inside.
correct labelling and sequencing of all conductors.
b) State two items that would be checked during the inspection of the new lighting installation containment system stating what is being checked for in each case.
choosing the correct switches and conductor size.
c) State one other sense which may be used during the inspection of the existing installation.
sense of smell.
_________________________________________________________________________________________
3. A test of continuity of protective conductors is to be carried out on the new lighting circuit to determine the (R1 + R2) value before the circuit is connected to the DB.
Describe, in detail, How this test is to be carried out.
___________________________________________________________________________________________
4. Describe, in detail, How the external earth fault loop impedance for the installation is carried out by direct measurement.
___________________________________________________________________________________________________
5. The client has complained that the single phase motor for the hoist at the rear of the premises has been slow and getting hot. Due to the length of run it is suspected that
there may be a voltage drop problem.
a) Determine the voltage drop for the circuit if the combined measured resistance of the line and neutral conductors is 0.38 (Ω) and the load current of the motor is 30 (A).
b) Determine whether the voltage drop calculated in (a) above meets the requirements of BS 7671.
c) Explain one course of action that could be taken if the voltage drop is exceeded on this circuit, giving reasons for your choice.
______________________________________________________________________________________________________
6. Describe, with the aid of a fully labelled diagram, the earth fault loop impedance path for the new lighting circuit.
_______________________________________________________________________________________________
END
I will add more questions on here tomorrow.
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