Power Station

Substation Substation

Distribution Infrastructure

(Network)

Low Voltage (LV)

distribution

NetworkSubstations

National Grid

High Voltage (HV) Transmission 66kV~400kV

Delta-StarTransformerHV to LV

Referred to as “WORKS” in The Electricity Act 1992 Defined as an(ELECTRICAL INSTALLATION)

in The Electricity Act 1992

Point of entry (POE)

Point of supply (POS)

TransmissionLine MechanicSubstation

MaintainerSubstationMaintainer

SubstationMaintainer

DistributionLine Mechanic

(Underground conductors)

(Overhead conductors)

CONSUMER’SBOUNDARY

Limits of work for Substation Maintainer & Line Mechanic

classes of registration

Electric line(Service Main)

Electric line

230V

400 V

600 V

AC

EndorsedDistribution

Line Mechanic