CPCS Working Near Services & Site Hazards 2

Question 1

What is 'flashover' in the context of overhead power lines?

Accepted Answer

Electricity arcing from a power line to nearby conductive objects without direct contact — potentially fatal

Answer

Flashover occurs when electricity arcs from a power line to a nearby conductive object — such as a crane boom — without direct contact. It can be fatal to the operator and to persons on the ground.

Question 2

What is the minimum safe distance from a 33 kV overhead line when using construction plant?

Accepted Answer

6 metres or as specified by the DNO (Distribution Network Operator)

Answer

Safe distances from overhead lines depend on voltage and must be confirmed with the DNO. For 33 kV lines the minimum is typically 6 metres, but the DNO must be consulted for site-specific guidance.

Question 3

Before plant operates near overhead lines, what physical controls should be in place?

Accepted Answer

Goal posts, height restrictors, and banksman to prevent plant approaching closer than the exclusion zone

Answer

Physical controls including goal posts (overhead barriers) and height restrictors are required to physically prevent plant from approaching the exclusion zone, backed by a banksman to monitor proximity.

Question 4

What is the colour coding for water mains in UK underground services?

Accepted Answer

Blue

Answer

Water mains are identified by blue in the UK underground services colour coding system. Striking a water main causes flooding and can undermine ground stability.

Question 5

What is a 'permit to dig' and when is it required?

Accepted Answer

A formal document authorising excavation work in an area with known underground services — required before any excavation near services

Answer

A permit to dig is a formal document that controls excavation in areas with underground services. It details the services present, precautions required, and authorises work to proceed. Required before excavation near any services.

CPCS Theory Practice Test

CPCS Theory Practice Test

CPCS Working Near Services & Site Hazards 2