CSCS Electrical Safety

Question 1

What voltage supply is required for portable electrical equipment used on construction sites under BS 7671?

Accepted Answer

110V via centre-tapped earth transformer

Answer

230V via standard socket

Answer

415V three-phase supply

Answer

12V extra-low voltage only

Question 2

What is the primary purpose of a Residual Current Device (RCD) on a construction site?

Accepted Answer

To detect earth leakage current and disconnect the supply rapidly

Answer

To prevent overloading of circuits

Answer

To regulate voltage fluctuations

Answer

To monitor energy consumption

Question 3

What is the safe exclusion zone distance for work near 400kV overhead power lines as specified by HSE guidance?

Accepted Answer

15 metres

Answer

3 metres

Answer

6 metres

Answer

9 metres

Question 4

How often must portable electrical equipment on a construction site undergo PAT testing as a general guideline?

Accepted Answer

Every 3 months

Answer

Every 12 months

Answer

Every 6 months

Answer

Only when visibly damaged

Question 5

Under the Electricity at Work Regulations 1989, who has a duty to ensure electrical systems are safe?

Accepted Answer

The duty holder — employers, self-employed persons, and employees

Answer

Only qualified electricians

Answer

The HSE inspector

Answer

Only the client who commissioned the work

Question 6

What is the correct procedure before carrying out electrical isolation of equipment on a construction site?

Accepted Answer

Switch off, isolate, lock off, prove dead using a voltage tester, and attach warning notices

Answer

Simply unplug the equipment and begin work

Answer

Ask a colleague to hold the switch in the off position

Answer

Turn off the main supply to the entire site