Over 100A Three Phase: The Essential Energy Approval Process Explained

Essential Energy covers regional and outer-metro NSW — including the outer fringes of Sydney's network footprint, the Southern Highlands, and much of regional NSW that High Demand Electrical services. Like Ausgrid and Endeavour, Essential Energy requires formal design approval for any low voltage customer switchboard rated above 100 amps per phase, and it applies one of the stricter compliance standards of the three networks.

Why over 100A matters to Essential Energy

If the switchboard you're installing is rated greater than 100A per phase, Essential Energy requires the design to be approved before you procure it — not after. Since 24 May 2021, all new low voltage customer switchboards above 100A per phase must comply with AS/NZS 61439, which is a more demanding assembly standard than many switchboard manufacturers were previously building to, and it's the single most common reason submissions get rejected.

Applications must be submitted with a proposed load, a single line diagram, power factor correction details where relevant, and a completed Switch Board Compliance Statement, sent to switchboard.review@essentialenergy.com.au using Essential Energy's required file naming convention: Address_Customer Name_Submitting Company Name_Submission Version. Essential Energy then responds with either "appears compliant" or "rejected" — there's no partial approval, so an incomplete or non-compliant submission goes straight back for revision.

Step 1: Establish the actual maximum demand

Every application starts with a maximum demand figure. For new builds, a Level 3 ASP designer calculates this to AS/NZS 3000 Appendix C. For existing sites — a rural property adding three phase for irrigation or workshop equipment, a regional commercial site adding EV chargers or solar — power logging gives Essential Energy real measured data from the site rather than a conservative desktop estimate, which can make the difference between a straightforward upgrade and an expensive network augmentation.

Step 2: Check capacity in the street or feeder

Because Essential Energy's network covers large, often lower-density areas, feeder and transformer capacity is checked carefully before any large load is approved. Rural and regional connections in particular can be constrained by feeder length and voltage drop, so this step can materially change both cost and scope compared to a metro connection.

Step 3: Submit the connection application

The application, proposed load and supporting technical documentation are lodged with Essential Energy. For anything beyond a basic residential job this is typically managed by a Level 2 ASP electrician working with a Level 3 ASP designer, since Essential Energy expects full technical backing, not just a request.

Step 4: Design and submit the switchboard

The switchboard is designed to AS/NZS 61439 and Essential Energy's requirements, and the Switch Board Compliance Statement, single line diagram and proposed load are prepared for submission to switchboard.review@essentialenergy.com.au, following the required naming convention exactly.

Step 5: Get switchboard design approval

Essential Energy reviews the submission and responds as appears compliant or rejected. AS/NZS 61439 non-compliance, incorrect file naming, and missing power factor correction details are the most common reasons a design pack is sent back — and because Essential Energy doesn't offer conditional approval, a rejection means a full resubmission.

Step 6: Installation

Once the design appears compliant, the switchboard is manufactured to AS/NZS 61439 and the approved design, then installed along with consumer mains, metering and any network-side work carried out by a Level 1 ASP electrician.

Step 7: Inspection

Essential Energy or its appointed inspector checks the completed installation against the approved design on site before energisation.

Step 8: Testing

Protection settings, earthing, insulation resistance and metering accuracy are tested and documented, with phase balancing confirmed for larger or multi-tenancy sites.

Step 9: Commissioning

The connection is energised, metering confirmed live, and the site formally handed over as a compliant Essential Energy connection.

How long does this take with Essential Energy?

A clean application with a fully compliant AS/NZS 61439 switchboard design typically runs six to ten weeks from application to commissioning — slightly longer than metro networks, reflecting the stricter compliance standard and, for regional sites, feeder capacity checks. A rejected submission restarts the design review clock, so getting AS/NZS 61439 compliance right first time matters more here than anywhere else.

Where projects usually get stuck

• Switchboards built to the older assembly standard instead of AS/NZS 61439, which Essential Energy will reject outright.
• Incorrect file naming on the submission to switchboard.review@essentialenergy.com.au, which delays processing even when the technical content is fine.
• No maximum demand data — either a proper calculation or a power logging study — behind the proposed load.
• Underestimating feeder or voltage-drop constraints on regional and rural connections.

HDE manages the full Essential Energy connection process

High Demand Electrical is Level 1, Level 2 and Level 3 ASP accredited, so we run this process end to end in Essential Energy's network — from power logging or max demand calculation, through AS/NZS 61439 switchboard design and approval, to installation, inspection, testing and commissioning.

If you're planning a supply upgrade beyond 100A three phase in an Essential Energy area, get in touch and we'll scope the application — and the compliance standard — before you commit to hardware.