electrical

Question 1

What document should be referred to for specific wiring details of domestic heating
controls?

Answer 1

Manufacturer’s instructions

Question 2

What is the most likely supply voltage type and rating used for a central heating
pump?

Answer 2

230 V a.c.

Question 3

What voltage would be found on a low voltage central heating wiring system?

Answer 3

24 V a.c.

Question 4

What domestic electrical circuit would incorporate the plug outlets?

Answer 4

Ring main circuit

Question 5

Which Earthing arrangement uses an installation of an earth electrode as part of
the earth fault path?

Answer 5

TT

Question 6

Which conductor connects an installation Main Earthing Terminal (MET) to the incoming
metallic Water Supply Service Pipe?

Answer 6

Main Protective Bonding Conductor

Question 7

Which conductors would normally connect two water pipes together within a bathroom location?

Answer 7

Supplementary Bonding Conductor

Question 8

Which protective devices operates under earth fault conditions only?

Answer 8

RCD

Question 9

What protective device operates when the system is overloaded?

Answer 9

circuit breaker

Question 10

Which fuse cartridge would be selected to provide overcurrent protection to the fused
connection unit to a 230v domestic central heating control system with a total load of 600
Watts?

Answer 10

3 a

Question 11

What protection method applies when installing circuits using single-core cable?

Answer 11

The cables must be enclosed in conduit

Question 12

What would most likely be the first thing to be damaged if the current in a cable exceeds
its current carrying capacity?

Answer 12

Cable insulation

Question 13

What is the recommended method used to secure a circuit breaker in the off position?

Answer 13

Locking device with unique key

Question 14

A circuit breaker located within a consumer’s control unit controlling a shower circuit
requires replacement. What is the correct part of the installation for carrying out safe
isolation?

Answer 14

The consumer unit main switch

Question 15

A ring-final circuit requires the addition of a fuse connection unit for a boiler. Where’s the
most suitable location to carry out safe isolation in order to carry out this work?

Answer 15

The consumer unit main switch

Question 16

What is the correct method of ensuring safety following safe isolation and locking off of
the circuit?

Answer 16

Retain the unique key with you

Question 17

Which faults is most likely to cause electrocution?

Answer 17

Loose connection

Question 18

What is the most likely fault if an appliance works intermittently?

Answer 18

Loose connection in the appliance plug

Question 19

What is the most likely fault that would cause an RCD to trip when an electric shower is
switched on using the local functional switch?

Answer 19

A fault between live and earth within the shower unit

Question 20

When wiring up a plug top, the connections should be made in a way to ensure that if the
cable is pulled with sufficient force to remove it from the plug. Which wire should be the
last to be broken?

Answer 20

Earth

Question 21

An intermittent fault exists in hot water immersion heater. It appears that the cable has
become brittle and the circuit keeps shorting out. What is the most likely cause of the
fault?

Answer 21

A non heat-resistant flex being used

Question 22

What fault is the most likely cause of brown discolouring around the front of a
socket-outlet?

Answer 22

Loose line connection within the plug of an appliance regularly used at the socket

Question 23

Fault diagnoses reveals a serious fault in a domestic installation which could result in
serious electric shock if not rectified. Which person should be informed immediately in
this situation?

Answer 23

Owner

Question 24

Fault diagnosis is being undertaken in a building during non-working hours (when the
building is unoccupied). A serious and life-threatening fault is discovered to the wiring of
a circuit and rectification of the fault will require major works. What action would be the
most appropriate in this situation?

Answer 24

The circuit should be securely isolated until the client can be informed of the risk

Question 25

What is the most likely consequence if a loose neutral connection within a lighting circuit is
not rectified?

Answer 25

Electric shock

Question 26

What is the reason for applying temporary electrical bonds to pipework?

Answer 26

They are applied before cutting a section of metallic pipe to minimise the risk of electric
shock should the pipe be carrying a residual fault current.

Question 27

What tool would be used to cut a copper conductor, within a flexible cable, to the correct
length?

Answer 27

Side Cutters/ Insulated Wire Cutters

Question 28

What type of connection is commonly used within a joint box used in domestic wiring
systems?

Answer 28

Screws

Question 29

What test would use a test voltage of 500 V d.c.?

Answer 29

Insulation resistance

Question 30

A test of safe isolation of an electrical system should be carried out using

Answer 30

an approved voltage indicating device

Question 31

What is resistance measured in?

Answer 31

Ohms

Question 32

Which type of electrical test is carried out to confirm that line and neutral
conductors are connected correctly and not crossed?

Answer 32

Polarity test

Question 33

What colour conductors should be connected to the line terminal of a three-pin
plug?

Answer 33

Brown