Change in the number of phases of a premises for battery storage

When installing an inverter with a battery energy storage system (BESS) at an existing two-phase (400 V phase-to-phase) or split-phase (460 V phase-to-phase) premises, consideration may be given to re-wiring all the electrical load of the premises to a single-phase.  To do this, and to meet the phase-balancing requirements set out in QECM clause 8.4, it will typically require the removal of a phase from the network to the premises.

Disconnecting a phase from a premises without following the correct process may lead to safety risks as the conductors will remain live.

To enable a change in the number of phases at the premises and the connection of an inverter installation with a BESS, the connection must proceed as follows:

The following must first be submitted for the change in phases:

• a Connect Application with Service Type Change to an Existing Connection;
• a Change to the number of Phases at the Premises; and
• a Supply Upgrade EWR (NB the BESS may increase maximum demand via AC charging).

After which, the following must be submitted for the inverter energy system installation or alteration:

• Connect Application; and
• EWR.

Please also consider the impact of the BESS on the maximum demand of the installation.