200A Three Phase Supply in Sydney: When You Need It and How to Get It Approved

200A three phase comes up for a specific band of Sydney properties: larger homes with pools, ducted air conditioning and EV charging all on one board, small-to-medium apartment buildings, commercial kitchens, and light industrial units. It's well above the 100A threshold where Ausgrid, Endeavour Energy and Essential Energy all require formal switchboard design approval, so a 200A connection is a full network application, not just a bigger board off the shelf.

Do you actually need 200A?

The honest answer is often no — not yet. A calculated maximum demand under AS/NZS 3000 Appendix C tends to be conservative, and plenty of sites that look like they need 200A on paper are drawing well under that in real life. Before committing to the cost and lead time of a 200A upgrade, it's worth confirming the number two ways:

• Calculated demand — a Level 3 ASP designer works through Appendix C for your actual load list: cooking, hot water, air conditioning, EV charging, pool equipment, and general power, with diversity factors applied.
• Measured demand — for an existing building, power logging with a Fluke or Dranetz logger over one to four weeks shows what the site actually draws per phase, which is frequently 50 to 70% of the calculated figure.

If the measured or calculated figure comfortably clears 100A but sits under 200A, a smaller upgrade — or load management on things like EV chargers — may get you there without the full 200A application.

The approval process for 200A three phase

Once 200A is confirmed as the right number, the process is the same >100A pathway that applies across all three NSW networks, with documentation requirements specific to whichever distributor serves the site:

1. Maximum demand calculation or power log — the figure that justifies the 200A request.
2. Application to the network — lodged with Ausgrid, Endeavour Energy or Essential Energy depending on location, including the proposed load and site details.
3. Capacity check in the street — the distributor confirms the local transformer and mains can support an extra 100A+ of demand. If not, network augmentation works may be required, which changes cost and timeline materially.
4. Switchboard design — a Level 3 ASP designer produces the main switchboard design: busbar and breaker ratings, protection settings, metering arrangement, and the network's required compliance statement (Ausgrid's Switchboard Compliance Statement, Endeavour's Compliance Statement for Main Switchboards Greater Than 100 Amps, or Essential Energy's Switch Board Compliance Statement, built to AS/NZS 61439).
5. Switchboard design approval — the network reviews the design pack before the board is manufactured. This is where most delays happen, usually from incomplete documentation rather than the design itself being wrong.
6. Installation — the approved switchboard is built, installed, and connected, including consumer mains and metering.
7. Inspection — the network or its appointed inspector checks the finished work against the approved design on site.
8. Testing — protection, earthing, insulation resistance, metering accuracy, and phase balance are tested and recorded.
9. Commissioning — the connection is energised and formally handed over as compliant.

What a 200A switchboard actually needs to handle

At 200A three phase, a switchboard is typically supporting a genuinely mixed load profile — three-phase EV charging, ducted or multi-split air conditioning, commercial cooking or a large domestic kitchen, pool and spa equipment, and general lighting and power. The design has to account for diversity across all of these without under-sizing busbars or protection, which is exactly why the network wants a proper design pack rather than a generic board.

How long does a 200A upgrade take?

For a clean application with the right maximum demand data and a compliant switchboard design submitted first time, budget six to ten weeks from application to commissioning. Add time if the street needs augmentation works, or if the first switchboard design submission gets rejected — both are common at this size of connection if the groundwork isn't done properly upfront.

HDE manages 200A upgrades end to end

High Demand Electrical is Level 1, Level 2 and Level 3 ASP accredited, so we handle the full pathway for a 200A three phase upgrade — power logging or max demand calculation, switchboard design and network approval, installation, inspection, testing and commissioning — across Ausgrid, Endeavour Energy and Essential Energy areas.

If you think your Sydney property needs 200A three phase, get in touch and we'll confirm the actual number before you commit to a design.