EAS practice exams
State ONE reason why the protective earth conductor is longer than the phase and neutral
conductors when fitting a three-core flexible cord to an appliance.
If strain is applied to the flexible cord the PEC will be the last to pull away from the appliance
terminals.
State TWO reasons why a two core flexible cord that has a rating sufficient to operate an
electric clock must not be used for a Class I electric drill.
No provision for the earthing of the drill.
Insufficient current carrying capacity
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When connecting a flexible cord to an Edison type screw lampholder it is preferable to connect
the neutral conductor to the outer contact. State the main safety reason why you would do this.
It minimises the risk of contact with the active (phase) conductor
A new two-core and earth PVC sheathed flexible cord is to be fitted to a 230V, Class I electric
heater. Describe the main sequence of actions involved in fitting the three pin plug to the
two-core and earth PVC sheathed flexible cord.
The description has to include:
● Removing the outer-sheath of the cord
● Applying the cord clamp to the sheath
● The protective earthing conductor is longer than the phase and neutral.
The conductors are terminated in the correct terminals.
● The conductor insulation is up to the terminals.
, ● The plug is assembled and there is no exposed conductors or basic insulation.
A new two-core and earth PVC sheathed flexible cord is to be fitted to a 230V, Class I electric
heater. After the flexible cord and plug have been fitted to the heater, what action does AS/NZS
3760 require to be taken to ensure the heater is safe to return to service?
A visual inspection
● An earth continuity test
● An insulation resistance test
State ONE set of colours for the conductors of the two-core and earth PVC sheathed flexible
cord. For each colour, state the polarity.
Brown Phase
Light Blue Neutral
Green/yellow Earth
A 230V, Class I, plug-in electrical appliance is controlled by a single pole switch. The appliance
has been disconnected from the power supply. You are testing the appliance with an ohmmeter
and find that the connections are not correct. For this appliance, describe the TWO situations
that would cause the neutral to be switched instead of the phase.
The neutral conductor was connected to the line side of the switch
● The phase and neutral can be transposed at the plug on the flexible cord
● The phase and neutral can be transposed at the internal terminals before the switch.
State ONE unsafe effect a phase and neutral transposition could create in an electrical
appliance.
Most of the internal wiring will be alive at 230V to earth.
● With the switch in the "OFF" position
In an office, a 16A MCB protects a final subcircuit consisting of three socket outlets supplying
various 230V plug-in electrical appliances. The appliances were operating normally until the
MCB tripped. When the MCB was reset, it tripped again. You have established that:
● The MCB is correctly rated for the circuit and is not faulty.
● The circuit is not faulty.
● The appliances are not overloading the circuit
(i) State the TWO reasons why the MCB keeps tripping.
For ONE of the reasons you have stated in (i), describe how you would test to establish that this
is the reason why the MCB keeps tripping.
1.
● A short to earth in an appliance. (1 mark)
State ONE reason why the protective earth conductor is longer than the phase and neutral
conductors when fitting a three-core flexible cord to an appliance.
If strain is applied to the flexible cord the PEC will be the last to pull away from the appliance
terminals.
State TWO reasons why a two core flexible cord that has a rating sufficient to operate an
electric clock must not be used for a Class I electric drill.
No provision for the earthing of the drill.
Insufficient current carrying capacity
Previous
Play
Next
Rewind 10 seconds
Move forward 10 seconds
Unmute
0:00
/
0:15
Full screen
Brainpower
Read More
When connecting a flexible cord to an Edison type screw lampholder it is preferable to connect
the neutral conductor to the outer contact. State the main safety reason why you would do this.
It minimises the risk of contact with the active (phase) conductor
A new two-core and earth PVC sheathed flexible cord is to be fitted to a 230V, Class I electric
heater. Describe the main sequence of actions involved in fitting the three pin plug to the
two-core and earth PVC sheathed flexible cord.
The description has to include:
● Removing the outer-sheath of the cord
● Applying the cord clamp to the sheath
● The protective earthing conductor is longer than the phase and neutral.
The conductors are terminated in the correct terminals.
● The conductor insulation is up to the terminals.
, ● The plug is assembled and there is no exposed conductors or basic insulation.
A new two-core and earth PVC sheathed flexible cord is to be fitted to a 230V, Class I electric
heater. After the flexible cord and plug have been fitted to the heater, what action does AS/NZS
3760 require to be taken to ensure the heater is safe to return to service?
A visual inspection
● An earth continuity test
● An insulation resistance test
State ONE set of colours for the conductors of the two-core and earth PVC sheathed flexible
cord. For each colour, state the polarity.
Brown Phase
Light Blue Neutral
Green/yellow Earth
A 230V, Class I, plug-in electrical appliance is controlled by a single pole switch. The appliance
has been disconnected from the power supply. You are testing the appliance with an ohmmeter
and find that the connections are not correct. For this appliance, describe the TWO situations
that would cause the neutral to be switched instead of the phase.
The neutral conductor was connected to the line side of the switch
● The phase and neutral can be transposed at the plug on the flexible cord
● The phase and neutral can be transposed at the internal terminals before the switch.
State ONE unsafe effect a phase and neutral transposition could create in an electrical
appliance.
Most of the internal wiring will be alive at 230V to earth.
● With the switch in the "OFF" position
In an office, a 16A MCB protects a final subcircuit consisting of three socket outlets supplying
various 230V plug-in electrical appliances. The appliances were operating normally until the
MCB tripped. When the MCB was reset, it tripped again. You have established that:
● The MCB is correctly rated for the circuit and is not faulty.
● The circuit is not faulty.
● The appliances are not overloading the circuit
(i) State the TWO reasons why the MCB keeps tripping.
For ONE of the reasons you have stated in (i), describe how you would test to establish that this
is the reason why the MCB keeps tripping.
1.
● A short to earth in an appliance. (1 mark)
