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WorksheetsCGV Electrical P2
Total questions: 16
Worksheet time: 8mins
What is the primary purpose of the earth cable in an electrical system?
To provide power to appliances
To reduce voltage
To provide a zero-volt path for fault current
To increase current flow
Which earthing system uses an earth rod driven into the ground?
TN-S
TN-C-S
TT
TN-C
In a TN-C-S system, where does the earth connection originate?
At the consumer unit
At the outer sheath of the supply cable
At the supplier's fuse, connected to the neutral conductor
At the earth rod
What size earth wire should be used to bond mains cold water and gas pipes?
6mm²
8mm²
10mm²
12mm²
Which of the following is NOT typically bonded in a domestic plumbing system?
Radiators
Plastic baths
Steel basins
Gas pipes
CSA stands for which of the following in relation to cable sizing?
Cable Sizing Area
Current Safe Amperage
Cross-Sectional Area
Cable Safety Assessment
Equipotential bonding is important in domestic plumbing systems because:
it reduces the risk of electric shock by equalizing potential differences
it increases water pressure in pipes
it prevents pipe corrosion by chemical means
it improves the taste of tap water
The key difference between a TN-S and a TN-C-S earthing system is:
In TN-S, the neutral and earth conductors are separate throughout, while in TN-C-S, they are combined in part of the system.
TN-S uses only a single conductor for both neutral and earth throughout the system.
TN-C-S does not provide any earthing at all.
TN-S and TN-C-S are identical systems with no differences.
If paint is present on a surface where a temporary bond is to be applied, what must be done?
The paint must be removed.
The surface should be sanded lightly.
A primer should be applied over the paint.
The paint should be left as is.
The purpose of a temporary continuity bond is:
to maintain electrical continuity during work on a circuit
to permanently connect two conductors
to insulate live wires
to increase the voltage in a circuit
Explain the function and importance of earthing in domestic electrical systems, including the role of the protective conductor, the consumer unit, and how earthing contributes to safety.
Earthing provides a safe path for fault current, protects users from electric shock, and ensures the consumer unit disconnects power in case of faults.
Earthing increases the voltage in the system, making appliances work faster and more efficiently.
Earthing is only used to improve the appearance of electrical installations and has no safety function.
Earthing is mainly for reducing electricity bills by preventing current leakage.
The three main types of earthing systems—TN-S, TN-C-S, and TT—differ in their arrangement and have specific implications for plumbers during installation or inspection. Which of the following correctly describes these differences?
TN-S has separate neutral and earth conductors, TN-C-S combines them partially, and TT uses a local earth electrode; each affects plumbing safety and bonding requirements differently.
TN-S and TT both use combined neutral and earth conductors, while TN-C-S uses only a local earth electrode.
All three systems use the same arrangement and have identical implications for plumbers.
TN-C-S and TT systems do not require any special consideration for plumbers during installation.
Equipotential bonding in a domestic property is important because it:
Reduces the risk of electric shock by ensuring all exposed metal parts are at the same potential.
Increases the voltage in the property for better appliance performance.
Eliminates the need for circuit breakers and fuses.
Allows water pipes to carry electrical current safely.
Which of the following best describes the function of a protective conductor in an electrical installation?
It is used only for decorative purposes.
It provides a path for fault current to safely return to earth.
It increases the resistance of the circuit.
It supplies power to electrical devices.
Why is it important to use the correct size of bonding conductor when connecting metal pipes in a domestic property?
To increase the voltage in the system.
To reduce the cost of materials.
To make the installation look neater.
To ensure the conductor can safely carry fault current without overheating.
What is the main safety risk if equipotential bonding is missing or inadequate in a bathroom?
Higher electricity bills.
Increased risk of electric shock due to potential differences between metal parts.
Reduced water pressure in the taps.
Corrosion of copper pipes.
