CITB Electrical Safety 2 — Questions and Answers
Question 1: What is the purpose of Portable Appliance Testing (PAT)?
- To confirm equipment is operating at full power
- To verify that portable electrical equipment is safe to use (Correct answer)
- To measure the voltage of the site electrical supply
- To test whether RCDs will trip correctly
Correct answer: To verify that portable electrical equipment is safe to use
PAT testing checks that portable electrical equipment is safe to use and identifies faults before they can cause injury or fire.
Question 2: What colour label typically indicates that electrical equipment has passed a PAT test?
- Red
- Green (Correct answer)
- Yellow
- Blue
Correct answer: Green
A green label indicates the equipment has passed PAT testing and is safe to use; a red label means it has failed and must not be used.
Question 3: Underground cables must always be treated as live unless:
- They are buried more than 1 metre deep
- They have been isolated and proved dead by a competent person (Correct answer)
- No cable markers are visible on the surface above them
- They have been in the ground for more than 10 years
Correct answer: They have been isolated and proved dead by a competent person
Underground cables must be assumed live until a competent person has safely isolated the supply and proved the cables are dead using appropriate test equipment.
Question 4: What tool should be used to locate buried electrical cables before excavating?
- A metal detector
- A Cable Avoidance Tool (CAT) (Correct answer)
- A depth gauge
- A ground-penetrating radar only
Correct answer: A Cable Avoidance Tool (CAT)
A Cable Avoidance Tool (CAT), used with a signal generator (Genny), detects buried cables and pipes to reduce the risk of striking them during excavation.
Question 5: What should you do if you accidentally strike an underground cable during excavation?
- Continue carefully and inspect the damage
- Fill in the hole and move to a different area
- Treat it as live, warn others, and contact emergency services and the cable owner (Correct answer)
- Check visually if the cable is damaged and carry on if it looks intact
Correct answer: Treat it as live, warn others, and contact emergency services and the cable owner
Striking an underground cable is an emergency — treat it as live, keep everyone away, and immediately call the emergency services and cable owner.
Question 6: What is the purpose of a 'permit to work' for electrical activities on a construction site?
- It allows any site worker to carry out electrical repairs
- It is a formal document that controls high-risk electrical work and ensures safe isolation (Correct answer)
- It gives permission to increase the voltage of site supply equipment
- It confirms that electrical tools have passed their PAT test
Correct answer: It is a formal document that controls high-risk electrical work and ensures safe isolation
A permit to work is a formal documented procedure that controls high-risk activities such as electrical work, ensuring proper isolation and authorisation before work starts.
Question 7: When must electrical isolation be carried out on a construction site?
- Only when replacing wiring or sockets
- Before any maintenance or repair work is carried out on electrical equipment (Correct answer)
- Only by qualified electricians undertaking permanent installation work
- When a piece of equipment is not in use overnight
Correct answer: Before any maintenance or repair work is carried out on electrical equipment
Electrical isolation must be carried out before any maintenance or repair work to prevent accidental energisation and the risk of electric shock.
CITB Electrical Safety 2
What is the purpose of Portable Appliance Testing (PAT)?