what instrument setting is used for conducting Insulation resistance tests ?
low ohms
M ohms
micro ohms
>100 ohms
what instrument setting is used for conducting Continuity of cpc tests ?
M ohms
low ohms
micro ohms
>100 ohms
which one of the following test readings for Insulation Resistance would satisfy BS7671 for a 230v AC ring final circuit ?
10 ohms
100 ohms
100k ohms
10M ohms
which one of the following test readings for Continuity of cpc would satisfy BS7671:2018 for a 230v AC lighting circuit ?
1M ohm
100 ohms
0.5 ohms
10M ohms
when conducting a Continuity of cpc test, what other test can be carried out at the same time, on the same circuit, using the same test instrument and settings ?
insulation resistance
polarity
continuity of ring final conductors
continuity of equipotential bonding conductors
what setting is used for conducting a Polarity test ?
M ohms
low ohms
m Seconds
k Amps
A circuit breaker for a socket circuit is tripping intermittantly. This occurrs even if there is nothing plugged in. The likely cause is ?
short circuit
continuity fault in live conductor
insulation failure
poor earthing continuity
a nail was accidently hammered through a 'hidden' lighting cable. The circuit Breaker for that circuit operates. this is an example of which type of fault ?
short circuit
continuity fault in live conductor
insulation failure
poor earthing continuity
damp getting into a cable can lead to which type of fault ?
short circuit
continuity fault in live conductor
insulation failure
poor earthing continuity
what is the function of a 'shorting lead' when conducting Continuity (R1 + R2) tests ?
it completes the live to cpc 'test loop'
it is used for linking'switch lives' during testing
it is used to connect live to neutral during the Polarity test only.
it is used to 'bond' the test instrument to Earth during testing
which is the correct sequence of testing ?
continuity of cpc, insulation resistance, polarity, continuity of ring final conductors
insulation resistance, polarity, continuity of ring final conductors, continuity of cpc
continuity of cpc, continuity of ring final conductors, insulation resistance, polarity
insulation resistance, polarity, continuity of cpc, continuity of ring final conductors
why is it important to 'zero' a test instrument prior to use during an earth continuity test ?
to ensure that the resistance of the test leads is added to the final reading
to ensure that the resistance of the test leads is deducted from the final reading
to ensure the batteries are in good order
to ensure that the instrument is earthed before use
which of the following should be checked prior to using a test instrument (select all appropriate answers)?
it should show no signs of damage
it should be checked for a current calibration mark
it should be checked for correct operation
that you are familiar with its operation and suitably qualified to proceed
In an industrial installation example, it is essential that a 3-phase motor rotates in the correct direction ONLY when it is first switched on. How can you ensure this prior to connecting the motor up?
run the motor up and swap any two phases over if it rotates the wrong way.
carry out a polarity test at the (motor) end of the circuit
conduct a polarity test at the origin of the installation
carry out a polarity test at the origin of the installation and at every point up to the motor terminals.
identify the test that is carried out under live test conditions
earth electrode resistance
prospective fault current
(r1+r2)
earth continuity test
identify the test that is carried out under live test conditions
insulation resistance
prospective short-circuit current
(r1+r2)
earth continuity test
identify the minimum insulation resistance value allowed for a SELV circuit
1M ohm
0.5 M ohm
2 M ohm
0.25 M ohm
identify the minimum insulation resistance value allowed for a 230v mains circuit
1M ohm
0.5 M ohm
2 M ohm
0.25 M ohm
identify the minimum insulation resistance value allowed for a 110v AC circuit on a construction site
1M ohm
0.5 M ohm
2 M ohm
0.25 M ohm
identify the maximum continuity value allowed for a main equipotential bonding conductor?