Commercial solar PV and battery storage is a specialty within electrical work. CEC commercial accreditation is a separate ticket on top of a standard electrical licence, the inverter and battery products change every year, and credible install requires bench depth across the 25-year warranty period. Rather than spread thin, Millar Electrics focuses on core commercial electrical work and refers solar and battery enquiries to CEC commercial-accredited installers and EPCs we'd use ourselves on a site we owned.
What we refer vs what we handle
The PV array, the inverter, the DC string design and the battery cabinet go to the EPC. Everything around it is ours: switchboard upgrades to absorb the new generation and storage loads, sub-mains uprating where the run can't carry the inverter's output, three-phase distribution out to the relevant boards, separately-metered sub-circuits for embedded networks or tenancy on-charging, and EV charger integration so daytime generation feeds the fleet rather than the grid. We coordinate timing with the EPC so the connection point is ready when their crew lands on site.
Where commercial solar and battery actually pays back
The economics that work on a commercial site aren't the residential economics. Demand charges (the bill component priced off your half-hour peak, not your kWh consumption) are usually the line that battery storage attacks. Time-of-use tariffs reward solar self-consumption during business hours but rarely justify exporting at the feed-in rate alone. Behind-the-meter EV charging during the solar window is increasingly the swing factor. A good EPC models all three against your actual interval data before quoting, and we sanity-check the modelling alongside our switchboard assessment so the system gets sized to the business case, not the roof area.
Standards the work has to meet
Commercial PV installations are governed by AS/NZS 5033 (PV array installation), grid-connect inverters by AS/NZS 4777.1 and .2 (grid-connected energy systems), and battery storage by AS/NZS 5139 (electrical installations — safety of battery systems). When we review a quote, that's what we check against — alongside CEC accreditation for the installer and the Victorian Distributed Energy Resources Register requirements for the inverter model. The interface with the rest of your installation (consumer mains, switchboard, isolation, surge protection) is AS/NZS 3000 — our side of the boundary.