WorksheetsPPT 1 Electrical Supplies and Equipment Identification Quiz
Total questions: 46
Worksheet time: 23mins
What is the purpose of a transformer in the electrical generation process?
To decrease the voltage
To increase the voltage
To convert AC to DC
To store electrical energy
From what voltage to what voltage does the transformer increase the electromotive force?
10,000 volts to 100,000 volts
22,000 volts to 400,000 volts
50,000 volts to 500,000 volts
30,000 volts to 300,000 volts
Why is electricity transmitted at very high voltages?
To reduce power loss through power lines
To increase power loss through power lines
To decrease the speed of transmission
To make the system more complex
What are the voltage levels of the supergrid mentioned in the document?
400kV and 275kV
132kV and 33kV
11kV and 400V
230V and 400V
What is the role of sub-stations in the National Grid?
They generate electricity.
They transform the electrical supply down to 11kV.
They increase the voltage to 400kV.
They distribute electricity directly to homes.
At what voltage is electricity typically distributed to large commercial buildings?
11kV
33kV
400V
230V
How is electricity finally distributed to customers?
Through overhead lines.
Via a network of radial circuits.
Directly from the generation station.
Through a series of transformers.
What voltage supply enters a dwelling at the mains intake?
110V
230V
240V
120V
What type of fuse is provided by the supplier for a dwelling?
Low breaking capacity (LBC) fuse
Medium breaking capacity (MBC) fuse
High breaking capacity (HBC) fuse
Standard fuse
What is the purpose of the sealed energy meter provided by the supplier?
To regulate voltage
To measure consumption
To control current
To provide backup power
What are the two conductors in the supply cable mentioned in the document?
Live and ground
Live and neutral
Neutral and earth
Phase and earth
Where does the earth cable start in the supply to the property?
At the main earth terminal (MET)
At the consumer unit
At the supplier’s fuse
At the main electrical supply
What does the main earth terminal (MET) connect to?
Only the consumer unit
Only extraneous metal conductors
All components requiring an earth
Only the main electrical supply
What is the primary purpose of the earth cable?
To provide a zero-volt path for fault current to flow to earth
To increase the voltage in a circuit
To act as a main power supply
To insulate electrical wires
What is another name for the earth cable?
Protective conductor
Voltage enhancer
Circuit breaker
Insulation wire
What does equipotential bonding ensure?
All metal parts are at the same potential or voltage
Increased electrical resistance
Decreased electrical flow
Enhanced power output
Why does the consumer unit need an earth?
To allow each circuit to have its own earth
To increase the circuit's voltage
To reduce the circuit's current
To disconnect the circuit
In electrical terms, what is it called when a person is in contact with live exposed parts of an electrical system?
Indirect contact
Direct contact
Insulated contact
Grounded contact
What is the electrical term for the contact of persons or livestock with exposed-conductive parts that have become live under fault conditions?
Direct contact
Indirect contact
Short circuit
Ground fault
What does TN-S stand for in earthing systems?
Terra (earth) Neutral - Separate
Terra (earth) Neutral - Combined - Separate
Terra Terra
Terra (earth) Neutral - Shared
What does TN-C-S stand for in earthing systems?
Terra (earth) Neutral - Separate
Terra (earth) Neutral - Combined - Separate
Terra Terra
Terra (earth) Neutral - Shared
What does TT stand for in earthing systems?
Terra (earth) Neutral - Separate
Terra (earth) Neutral - Combined - Separate
Terra Terra
Terra (earth) Neutral - Shared
In a TN-S system, where does the earth start?
At the main switch
At the outer sheathing of the supply cable
At the gas meter
At the consumer's tails
What is the size of the main earthing connection in a TN-S system ?
5mm²
10mm²
16mm²
20mm²
What is the size of the circuit protective conductors in the TN-S system diagram?
5mm²
10mm²
16mm²
20mm²
In a TN-C-S system, where does the earth connection start?
At the main electrical supply
At the consumer unit
At the incoming supplier’s fuse
At the copper cold water supply
What is required for a TT earthing arrangement?
An earth rod driven into suitable ground
A metal plate buried underground
A plastic rod inserted into the soil
A wooden stake placed in the ground
What does CSA stand for in the context of cable sizing?
Cable Size Area
Cross-Sectional Area
Conductor Size Area
Current Supply Area
What is the minimum CSA for bonding conductors in a TT system?
4mm²
5mm²
6mm²
7mm²
What type of properties are three-phase supplies normally associated with?
Residential properties
Industrial and commercial properties
Agricultural properties
Recreational properties
What is the voltage step down from and to in a substation transformer for three-phase supplies?
11kV to 230V
11kV to 400V
400V to 230V
230V to 11kV
What type of coil is used as the primary coil in a substation transformer for three-phase supplies?
Star
Delta
Circular
Square
What is the potential difference between any two of the three phases in a three-phase supply?
230V
400V
11kV
600V
In which type of property is it unlikely for a domestic plumber to encounter a three-phase supply?
Commercial properties
Residential homes
Industrial buildings
Medical facilities
Who should be contacted to carry out three-phase electrical work?
A domestic plumber
A competent electrician
A building inspector
A property manager
Which of the following is a location where three-phase supplies may be present?
Residential homes
Small retail shops
Agricultural and horticultural land
Single-family houses
What is the voltage level of the substation transformer ?
11 kV/400 V
10 kV/300 V
12 kV/500 V
9 kV/350 V
Which phase is connected to the 400 V three-phase load?
Brown phase
Blue phase
Red phase
Yellow phase
What is the voltage level of the single-phase load in the diagram?
230 V
240 V
220 V
250 V
What is the color code for the phase (live) wire in single-phase 230V installations?
Blue
Brown
Green
Yellow
In single-phase 230V installations, what color is used for the neutral wire?
Green
Yellow
Blue
Brown
What are the colors used for the earth wire in single-phase 230V installations?
Green and yellow
Blue and brown
Red and black
Grey and black
For three-phase 400V installations, what is the color code for L2?
Brown
Black
Grey
Blue
What were the color codes for the live wire in single-phase installations before 2004?
Brown
Red
Blue
Black
In three-phase installations pre-2004, what color was used for L3?
Red
Yellow
Blue
Grey
What year did the harmonisation of cable colour codes occur?
2004
1999
2010
1995
