C&G 2381/2391 past papers............again?
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Hi Been trawling all the sites I can think of to see if I can get any sample questions for the 2381 and came across this thread. Did you have any luck getting any questions ??
I'm afraid I have'nt been able to track any down
Got one set that had been scanned in but I could'nt read them
If you got/have any could you let me know
Cheers
OS
I'm afraid I have'nt been able to track any down
Got one set that had been scanned in but I could'nt read them
If you got/have any could you let me know
Cheers
OS
Igot some I got from the internet the other day on testing can't remember the site - google searched for "GS38 voltage indicator" and loads of stuff came up. e-mail me at [email protected]. and i'll send them as attachment
Sample questions and answers 2391 theory exam.
Twenty short answer questions.
Answer these questions as statements, do not write compositions! Remember each point is usually worth only one mark.
The questions are from City and Guilds but the answers are mine.
An installation has been seriously overloaded and needs investigation. State the
type of inspection and test that would be required.
Documentation that will need to be completed.
Periodic inspection and test
Periodic Inspection Report including an Inspection Schedule and a Test Schedule
State the
statutory document that is relevant to inspection and testing
non-statutory document that is relevant to electrical test equipment
non-statutory document that is relevant to The Requirements for Electrical Installations
Electricity at Work Regulations 1989
HSE GS38
BS7671 2001
State the person who should
decide when the first periodic test on an installation should be carried out
decide when later periodic tests on an installation should be carried out
agree with the inspector the extent and limitations of a periodic inspection and test
Designer / Inspector / Client
State the form of protection that is offered by each of the following
placing out of reach
SELV
protection against direct contact
protection against direct and indirect contact
State the instrument required for each of the following tests
continuity of protective conductors
insulation resistance
live polarity
low resistance ohmmeter
insulation resistance ohmmeter
approved voltage indicator
State 3 circumstances that would result in an increase in conductor resistance
Increase in conductor temperature due to overload
Increase in conductor temperature due to fault current
Increase in conductor temperature due to an increase in ambient temperature
Reduction of csa
Increase in conductor length
The continuity of a lighting circuit protective conductor is to be tested. If the test method uses a temporary link between phase and earth in the distribution board, state
at which points in the circuit the test should be conducted
the conductors between which the tests should be made
the significance of the test reading at the end of the circuit
at each point
phase and cpc
R1+R2 for the circuit
The steel conduit of an installation is used as the cpc. State the three stages of the test that may b needed to check its continuity.
Actually, there are 4 stages;
Thorough inspection along its length
Test with a low resistance ohmmeter
Test with an earth loop impedance tester
May require a further test using a low resistance high current ohmmeter (output 50vac with a test current circa 25 amps)
For a ring final circuit wired in p.v.c. twin with c.p.c. state the
instrument used to conduct a continuity test
reason why phase to c.p.c. readings at each socket increase slightly to the mid point of the ring then decrease again
other test that is automatically conducted
low resistance ohmmeter
difference in c.s.a and therefore resistance
polarity
The insulation of a 600v discharge lighting installation is to be tested. State
test instrument to be used
test voltage to be applied
minimum value of insulation resistance
Insulation resistance ohmmeter
1000v dc
1megohm
For an insulation resistance test on a 230v installation. State the
minimum value of resistance acceptable
value below which, further investigation is required
minimum value of each circuit due to (c) above
0.5 megohm
2 megohm
2 megohm
For an installation in a bathroom, state the
type of socket outlet permitted excluding shaver sockets
location of zone 1
maximum rating of an rcd protecting a shower circuit
SELV
Within the bathtub or shower basin
None stated in BS7671 but presumably it will provide supplementary protection against direct contact, thus 30ma is maximum.
State the IP codes which should apply to each of the following
accessible top surfaces of enclosures
an intermediate barrier inside an enclosure
IP4X
IP XXB
State the three main reasons for conducting a polarity test on a new installation prior to it being energised.
To ensure that all single pole devices are connected in the phase conductor only
To ensure that the centre contact of ES lampholders are connected to the phase conductor only
To ensure the correct connection of accessories and socket outlets
The total loop impedance of a circuit may be calculated using the external loop impedance, the length and milliohm resistance of the circuit conductors, and a correction factor of 1.2 for operating temperature. State the formula used
Zs = Ze + (R1 + R2) x 1.2 / 1000
State the
important check to be made regarding equipotential bonding conductors before carrying out a loop impedance test on a circuit
action to be taken regarding the earthing conductor prior to conducting an external loop impedance test
precaution to be taken before conducting the test at (b)
You used to have to disconnect them. NO LONGER REQUIRED
Should be disconnected from MET
Isolate installation
A test is to be conducted on a lightning conductor earth electrode. State the
instrument to be used
names of the other two electrodes to be used in the test
Earth electrode resistance tester
Potential spike. Current spike
State three reasons for the use of a 500ma rcd in an installation
To provide protection against INDIRECT contact
To provide a measure of protection against fire
To help reduce nuisance tripping where protective conductor currents are present
State
why a test on an rcd must not be conducted before a loop impedance test
the maximum test current to be applied to a 10ma rcd used as supplementary protection against direct contact
the maximum test current that needs to be applied to a 100ma rcd
The earth loop must be low enough to ensure that the rise in voltage due to test current injected to test the rcd will not cause dangerous voltages to occur between installation earthed metalwork and earth.
50ma
100ma
A single phase TN-C-S installation has a measured value of external loop impedance of 0.015ohms. Show by calculation the expected value of prospective fault current at the origin.
Ipfc = Uo / Ze. Thus a prospective fault current of circa 16Ka can be expected at this point.
Twenty short answer questions.
Answer these questions as statements, do not write compositions! Remember each point is usually worth only one mark.
The questions are from City and Guilds but the answers are mine.
An installation has been seriously overloaded and needs investigation. State the
type of inspection and test that would be required.
Documentation that will need to be completed.
Periodic inspection and test
Periodic Inspection Report including an Inspection Schedule and a Test Schedule
State the
statutory document that is relevant to inspection and testing
non-statutory document that is relevant to electrical test equipment
non-statutory document that is relevant to The Requirements for Electrical Installations
Electricity at Work Regulations 1989
HSE GS38
BS7671 2001
State the person who should
decide when the first periodic test on an installation should be carried out
decide when later periodic tests on an installation should be carried out
agree with the inspector the extent and limitations of a periodic inspection and test
Designer / Inspector / Client
State the form of protection that is offered by each of the following
placing out of reach
SELV
protection against direct contact
protection against direct and indirect contact
State the instrument required for each of the following tests
continuity of protective conductors
insulation resistance
live polarity
low resistance ohmmeter
insulation resistance ohmmeter
approved voltage indicator
State 3 circumstances that would result in an increase in conductor resistance
Increase in conductor temperature due to overload
Increase in conductor temperature due to fault current
Increase in conductor temperature due to an increase in ambient temperature
Reduction of csa
Increase in conductor length
The continuity of a lighting circuit protective conductor is to be tested. If the test method uses a temporary link between phase and earth in the distribution board, state
at which points in the circuit the test should be conducted
the conductors between which the tests should be made
the significance of the test reading at the end of the circuit
at each point
phase and cpc
R1+R2 for the circuit
The steel conduit of an installation is used as the cpc. State the three stages of the test that may b needed to check its continuity.
Actually, there are 4 stages;
Thorough inspection along its length
Test with a low resistance ohmmeter
Test with an earth loop impedance tester
May require a further test using a low resistance high current ohmmeter (output 50vac with a test current circa 25 amps)
For a ring final circuit wired in p.v.c. twin with c.p.c. state the
instrument used to conduct a continuity test
reason why phase to c.p.c. readings at each socket increase slightly to the mid point of the ring then decrease again
other test that is automatically conducted
low resistance ohmmeter
difference in c.s.a and therefore resistance
polarity
The insulation of a 600v discharge lighting installation is to be tested. State
test instrument to be used
test voltage to be applied
minimum value of insulation resistance
Insulation resistance ohmmeter
1000v dc
1megohm
For an insulation resistance test on a 230v installation. State the
minimum value of resistance acceptable
value below which, further investigation is required
minimum value of each circuit due to (c) above
0.5 megohm
2 megohm
2 megohm
For an installation in a bathroom, state the
type of socket outlet permitted excluding shaver sockets
location of zone 1
maximum rating of an rcd protecting a shower circuit
SELV
Within the bathtub or shower basin
None stated in BS7671 but presumably it will provide supplementary protection against direct contact, thus 30ma is maximum.
State the IP codes which should apply to each of the following
accessible top surfaces of enclosures
an intermediate barrier inside an enclosure
IP4X
IP XXB
State the three main reasons for conducting a polarity test on a new installation prior to it being energised.
To ensure that all single pole devices are connected in the phase conductor only
To ensure that the centre contact of ES lampholders are connected to the phase conductor only
To ensure the correct connection of accessories and socket outlets
The total loop impedance of a circuit may be calculated using the external loop impedance, the length and milliohm resistance of the circuit conductors, and a correction factor of 1.2 for operating temperature. State the formula used
Zs = Ze + (R1 + R2) x 1.2 / 1000
State the
important check to be made regarding equipotential bonding conductors before carrying out a loop impedance test on a circuit
action to be taken regarding the earthing conductor prior to conducting an external loop impedance test
precaution to be taken before conducting the test at (b)
You used to have to disconnect them. NO LONGER REQUIRED
Should be disconnected from MET
Isolate installation
A test is to be conducted on a lightning conductor earth electrode. State the
instrument to be used
names of the other two electrodes to be used in the test
Earth electrode resistance tester
Potential spike. Current spike
State three reasons for the use of a 500ma rcd in an installation
To provide protection against INDIRECT contact
To provide a measure of protection against fire
To help reduce nuisance tripping where protective conductor currents are present
State
why a test on an rcd must not be conducted before a loop impedance test
the maximum test current to be applied to a 10ma rcd used as supplementary protection against direct contact
the maximum test current that needs to be applied to a 100ma rcd
The earth loop must be low enough to ensure that the rise in voltage due to test current injected to test the rcd will not cause dangerous voltages to occur between installation earthed metalwork and earth.
50ma
100ma
A single phase TN-C-S installation has a measured value of external loop impedance of 0.015ohms. Show by calculation the expected value of prospective fault current at the origin.
Ipfc = Uo / Ze. Thus a prospective fault current of circa 16Ka can be expected at this point.
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