CSCS Electrical Safety 2

Question 1

Why is 110V preferred over 230V for portable tools on construction sites?

Accepted Answer

The centre-tapped earth system limits maximum shock voltage to 55V, greatly reducing the risk of a fatal shock

Answer

It uses less electricity and reduces running costs

Answer

It requires smaller, lighter cables

Answer

230V tools are not available for construction use

Question 2

What does a Residual Current Device (RCD) do?

Accepted Answer

Detects an imbalance caused by an earth fault and rapidly disconnects the power supply

Answer

Reduces the supply voltage to a safe level

Answer

Tests electrical equipment to confirm it has passed PAT

Answer

Increases the working life of power tools

Question 3

Which of the following is a visual warning sign that electrical equipment may be unsafe to use?

Accepted Answer

The outer casing is cracked or has pieces broken away

Answer

The cable is neatly coiled and secured

Answer

The plug is firmly fitted with no missing pins

Answer

The equipment carries a current PAT test label

Question 4

Who is qualified to carry out repairs on electrical equipment or installations on a construction site?

Accepted Answer

A competent electrician with the relevant training and qualifications

Answer

Any worker who feels confident doing so

Answer

The site manager after completing the site induction

Answer

Only the original equipment manufacturer

Question 5

What is the primary function of the earth wire in an electrical circuit?

Accepted Answer

To provide a low-resistance fault path so protective devices operate and disconnect the supply

Answer

To carry the main working current to the equipment

Answer

To reduce the operating voltage of the tool

Answer

To improve the efficiency and performance of the motor

Question 6

What steps should be taken before excavating in an area where underground electrical cables may be present?

Accepted Answer

Obtain service drawings, use a Cable Avoidance Tool (CAT), and follow safe digging procedures

Answer

Start digging slowly and look for cables as you go

Answer

Ask a colleague whether they remember seeing any cables

Answer

Work as quickly as possible to minimize exposure time

Question 7

Which specialist tool is used to detect the electromagnetic field emitted by buried electrical cables before excavation?

Accepted Answer

A Cable Avoidance Tool (CAT)

Answer

A standard metal detector

Answer

A thermal imaging camera

Answer

A standard electric drill set to reverse