If you’re running a business in Melbourne’s western suburbs and your electrical system is struggling to keep up, equipment underperforming, circuit breakers tripping, or your electrician telling you that you can’t add another appliance without an upgrade — three-phase power is almost certainly the answer.

This guide covers what a three-phase upgrade actually involves for a commercial property, what it costs in 2025, how the Powercor process works, and what you need to check before committing. If you want the full picture including residential upgrades, see our three-phase power installation page.

Which Melbourne Businesses Need Three Phase Power?

Three-phase power isn’t always necessary, but for a growing number of businesses in Melbourne’s western suburbs, it’s either essential or strongly worth considering. Common triggers include: Adding equipment with high power draw — industrial refrigeration, commercial kitchen equipment, large compressors, CNC machinery, welding equipment and large HVAC systems all commonly require three-phase supply to operate correctly.

Expanding operations or taking on a larger tenancy, if you’re growing into a bigger space or adding production capacity, your single-phase supply may not have the headroom. Installing EV charging for a fleet or customers, commercial EV charging infrastructure almost always requires three-phase supply.

Whether you’re charging your own vehicles or offering charging to customers, the upgrade needs to happen first. New commercial fit-out or build, if you’re fitting out a new premises, completing the three-phase upgrade before landscaping, concrete and fitout work is complete will save significant cost on trenching.

Running multiple high-demand systems simultaneously, even if no single piece of equipment requires three-phase, running multiple large loads at once on single-phase causes voltage drops, equipment wear and unreliable performance.

How Much Does a Three Phase Upgrade Cost for a Melbourne Business in 2026?

Commercial three-phase upgrade costs in Melbourne’s western suburbs vary depending on the size of your premises, your existing switchboard, the type of supply connection and what Powercor work is involved.

PRICING TABLE:

Underground supply — existing business | $5,000 – $8,000
Underground supply — new build (pre-landscaping) | $3,500 – $5,000
Overhead supply | $5,000 – $8,000
With switchboard upgrade | Add $1,200 – $3,000
Large commercial / industrial installation | $8,000 – $15,000+

All prices exclude GST and Powercor connection fees. Truck appointment fees (disconnection and reconnection) are charged separately by Powercor at approximately $400–$500 per

What drives the final price up or down:

• Distance from street supply — longer cable runs between the street and your meter/switchboard increase materials and labour costs.
• Trenching requirements — underground installations requiring excavation through concrete, established paving or landscaping add significant cost. If you’re in a new build or haven’t yet completed landscaping, completing the three-phase upgrade first is the single biggest way to reduce your total cost.
• Switchboard condition — your switchboard must comply with current Australian standards before Powercor will reconnect your supply. If it doesn’t, it needs to be upgraded as part of the job. This is non-negotiable and is something we assess and quote for upfront.
• Supply pit installation — if your project requires a new underground supply pit, costs typically range from $6,000 to $10,000 for that component. We manage the application and coordination with Powercor for pit installations. Powercor fees —
• Powercor charges separately for their connection work. We itemise these clearly in your quote so there are no surprises.

Electrx provides fully itemised, transparent quotes. You’ll know exactly what you’re paying for before any work begins.

What’s Involved in a Commercial Three Phase Upgrade — The Powercor Process

In Melbourne’s western suburbs, Powercor is the electricity distributor. A three-phase upgrade isn’t something you organise directly with Powercor yourself — it requires a licensed electrical contractor to submit a Service Alteration Request and manage the process on your behalf. Here’s how it works:

Step 1 — Site assessment and quote We assess your current electrical setup, confirm whether overhead or underground supply applies to your premises, identify any switchboard work required, and provide a fully itemised quote. For commercial properties we also assess your load requirements to make sure the upgrade is sized correctly for your operations.

Step 2 — Powercor application We submit the Service Alteration Request to Powercor and manage all required documentation. Processing typically takes one to three weeks.

Step 3 — Electrical work Once approved, we complete the switchboard upgrade (if required), install new three-phase consumer mains cabling, and prepare the premises for Powercor’s connection work.

Step 4 — Disconnection, connection and inspection Two Powercor truck appointments are required — disconnection and reconnection. We schedule both and coordinate the attendance of an independent certified electrical inspector for the reconnection. Where possible we aim to complete all work and restore power within a single day to minimise disruption to your business.

Step 5 — Certificate of Electrical Safety Once the upgrade is complete and inspected, we issue your Certificate of Electrical Safety. If you’re a tenant, this documentation will also satisfy your landlord’s requirements for any electrical alterations to the premises.

Total timeframe: typically two to four weeks from quote to energisation, depending on Powercor’s processing and scheduling.

Leased Premises — What to Check Before You Commit

If you’re a tenant rather than a property owner, there are a few things to sort out before proceeding with a three-phase upgrade: Landlord approval, you’ll need written consent from your landlord before making any permanent alterations to the electrical supply. In most cases this is straightforward, but get it in writing before you commission the work. Lease terms — check your lease for make-good obligations.

Some leases require electrical alterations to be reversed at the end of the tenancy. It’s worth clarifying this with your landlord or solicitor before committing to the upgrade cost. Remaining lease term — if you have less than two or three years remaining on your lease, weigh the upgrade cost against the benefit you’ll actually get from it. For longer leases or owned premises, the investment almost always makes sense.

Maintenance and Testing After Your Three Phase Upgrade

Once your three-phase system is installed, routine maintenance keeps it running safely and reliably. For commercial properties this means: Periodic switchboard inspections to check for signs of overloading, loose connections or deteriorating components. Testing and tagging of portable electrical equipment on a regular schedule appropriate to your business type. An electrical maintenance schedule, particularly important for businesses running heavy machinery or equipment on continuous cycles.

Electrx offers commercial electrical maintenance across Melbourne’s western suburbs. If you’d like to set up a maintenance schedule alongside your upgrade, let us know at the quote stage.

Ready to Upgrade? Here’s What to Do Next

The fastest way to get a clear picture of what a three-phase upgrade will cost and involve for your specific premises is a free on-site assessment. We’ll assess your current supply, identify any switchboard work required, and give you a fully itemised quote with no obligation. We’re based in Brooklyn and service businesses across Melbourne’s western suburbs and inner city — including Footscray, Yarraville, Sunshine, Braybrook, Altona, Williamstown, Newport, Point Cook, Hoppers Crossing, Werribee, Tarneit, Truganina, Caroline Springs and West Melbourne

. See our full three-phase power installation page for upgrades and pricing.

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Electrx Electricians | 2a/46-50 Buchanan Rd, Brooklyn VIC 3012 Licence REC 31135 | Energy Safe Victoria Registered | 400+ Five-Star Google Reviews