Map loads by phase before selecting equipment
A three-phase service does not automatically mean every appliance uses three phases. Many household circuits remain single-phase and may be unevenly distributed. Record large loads such as EV chargers, heat pumps, ovens, pumps and workshops by phase. This matters for inverter current limits, export rules and what remains powered during an outage.
Understand the inverter topology
A three-phase hybrid inverter, three single-phase inverters and a mix of solar and battery inverters can behave differently. Some systems balance power across phases while others are constrained by per-phase output. Network operators may also impose phase-imbalance or per-phase export limits. Use the exact wiring architecture rather than treating a three-phase meter as one undifferentiated power channel.
Backup can be three-phase, single-phase or partial
Some residential battery systems support three-phase backup; others create backup on only selected circuits or one phase. A three-phase motor may not start if the backup supply is only single-phase. Confirm both steady-state power and surge behaviour for the backed-up circuits and make sure protective devices remain appropriate in island mode.
Metering and export control must see the whole connection
The control meter needs to measure the relevant phases and communicate with the inverter or energy-management system. Incorrect current-transformer orientation or phase mapping can cause unstable export control and misleading monitoring. Commissioning should compare the inverter portal with a known load change on each phase.
Future electrification can change the balance
Adding an EV charger or heat pump later can shift phase demand and battery requirements. Reserve panel space, communications paths and inverter capacity where reasonable. A design that barely meets today’s phase current can become awkward to expand, so include likely future loads in the initial site plan even if they are not installed immediately.
Use the checks together
Heat-pump load planning Battery-inverter compatibility guide should be used alongside the equipment manuals and local electrical requirements.