NEBOSH CC Electrical Hazards on Site 4

Question 1

What minimum qualification should an electrician have to carry out electrical installation work on a construction site?

Accepted Answer

Demonstrable competence such as an NVQ Level 3 or equivalent with relevant experience

Answer

Electricians carrying out installation work should be competent, typically demonstrated by holding an NVQ Level 3 in Electrical Installations or equivalent, with relevant practical experience. Competence must be appropriate to the specific work.

Question 2

What is the function of a transformer on a construction site?

Accepted Answer

To reduce the mains supply voltage (typically 230V) to the safer 110V used for portable tools

Answer

A step-down transformer reduces the mains 230V supply to the safer 110V used for portable tools on construction sites. The centre-tapped earth configuration ensures the maximum voltage to earth is only 55V, limiting shock severity.

Question 3

What is a 'dead leg' in the context of site electrical supply?

Accepted Answer

A section of electrical cable that is energised but not connected to any load

Answer

A dead leg is a section of energised electrical cable or pipe that is not connected to a load but remains live. These are hazardous because workers may not know the cable is live, especially if it appears abandoned or decommissioned.

Question 4

What is the safe method for testing whether electrical equipment is dead before commencing work?

Accepted Answer

Use an approved voltage indicator or multi-meter to test between all conductors and earth

Answer

The only safe method is to use an approved voltage indicator (test instrument) to test between all live conductors and between each conductor and earth. The instrument itself should be tested before and after use to confirm it is working correctly.

Question 5

Which type of cable is suitable for use outdoors on a construction site?

Accepted Answer

Heavy-duty rubber or armoured cable rated for outdoor use

Answer

Outdoor construction site cables must be heavy-duty rubber-insulated or armoured cables designed to withstand the mechanical damage, moisture and UV exposure typical of site conditions. Standard indoor cables are not suitable.

NEBOSH Construction Certificate Practice Test

NEBOSH Construction Certificate Practice Test

NEBOSH CC Electrical Hazards on Site 4