Split System Installation Sydney: The Electrician's Guide

Written by Chris · Licensed Level 2 ASP Electrician · Licence 397193C

Do you need an electrician as well as an air conditioning installer for a new split system? Yes, a split system installation involves two trades, your air conditioning installer handles the refrigerant and mechanical side, while a licensed electrician handles the dedicated circuit, wiring and compliance certificate. This guide covers what the electrical side involves so you know what to expect and what to ask before booking.

⚡ Quick Answers: Split System Electrical Work

• Do I need an electrician for a split system? Yes, all wiring and circuit connection for a fixed air conditioning unit must be done by a licensed electrician in NSW.

• What does the electrician actually do? Run a dedicated circuit from the switchboard, fit an isolator switch near the outdoor unit, and test and certify the connection.

• Can my switchboard handle a new split system? Only if it has a spare circuit breaker slot and safety switches, an older or full board may need upgrading first.

• How much does the electrical work cost? Typically $250 to $650 for a standard dedicated circuit and isolator, more if a switchboard upgrade is needed.

• Do I get a compliance certificate? Yes, a Certificate of Compliance for Electrical Work (CCEW) is issued for the new circuit.

Why a Licensed Electrician Is Required

In New South Wales, all electrical work, including the wiring and circuit connection for a split system air conditioner, must be carried out by a licensed electrician. Connecting a fixed appliance to your home's wiring without one is illegal and can void your home insurance.

The electrical work involved in a split system installation includes:

• Running a dedicated circuit from the switchboard to the indoor unit

• Installing the correct cable size for the unit's rated current draw

• Fitting a weatherproof isolator switch near the outdoor unit, required by AS/NZS 3000

• Confirming the switchboard has capacity for a new circuit

• Testing and commissioning the connection

• Issuing a Certificate of Compliance for Electrical Work (CCEW)

Some air conditioning installers also hold an electrical licence and can do both sides of the job. If yours doesn't, you'll need a separate licensed electrician for the wiring.

What Happens During the Electrical Side of the Job

1. Switchboard capacity check

Before any wiring starts, the electrician checks whether your switchboard has a spare circuit breaker slot. Most split systems draw between 15A and 32A depending on size, a small bedroom unit typically needs a 15A circuit, while a larger living room system may need 20A or 25A.

If your switchboard is full or old, with ceramic fuses or no safety switches, it may need upgrading before installation can proceed. Read our switchboard upgrades overview for what that involves and what it typically costs.

2. Running the dedicated circuit

Every split system should be on its own dedicated circuit, its own cable and circuit breaker, not shared with lights, power points or other appliances. This stops nuisance tripping when the unit starts up and protects other appliances from voltage fluctuations during heavy use. If you're already dealing with a safety switch that trips often, see our guide on why a safety switch keeps tripping.

The electrician runs a cable from the switchboard through the wall cavity or roof space to where the indoor unit will sit. Longer cable runs need a heavier cable gauge to avoid voltage drop.

3. Isolator switch installation

AS/NZS 3000 requires a lockable isolator switch installed within sight of, and accessible from, the outdoor unit of any fixed air conditioning system. This lets a technician safely isolate the unit for servicing without going back to the switchboard. It's a legal requirement for any new split system installation in NSW, and is often missing on older systems.

4. Wiring the indoor and outdoor units

The indoor and outdoor units are connected by refrigerant lines, handled by the aircon installer, and electrical control wiring, handled by the electrician. The electrician connects power to the outdoor unit and terminates the control wiring so the remote and thermostat function correctly.

5. Testing and compliance certificate

Once wiring is complete, the electrician tests the circuit, checking insulation resistance, earth continuity and correct polarity, before switching on. A Certificate of Compliance for Electrical Work (CCEW) is issued for the new circuit, our guide to the CCEW explains what it covers. Keep a copy, you may need it if you sell your home.

How Much Does the Electrical Work Cost in Sydney?

The electrical side of a split system installation is separate from the cost of the unit itself and the aircon installer's labour. Here's a realistic breakdown:

For a standard bedroom or living room split system where the switchboard already has a spare slot, expect to pay $350 to $650 for the electrical work on top of your aircon installation cost. These figures are indicative, a site visit confirms the final price for your job.

Choosing the Right System Size

System size affects both running costs and the electrical work required. An undersized unit runs continuously without reaching temperature, an oversized one short cycles and wears out faster. As a rough guide for Sydney homes:

• Small bedroom, up to 20 square metres: around a 2.5kW system on a 15A circuit

• Medium bedroom or study, 20 to 35 square metres: around a 3.5kW system on a 15A circuit

• Large living room or open plan, 35 to 60 square metres: around 5 to 7kW on a 20A circuit

• Very large open plan, 60 to 80 square metres: around 8 to 9kW on a 20A to 25A circuit

Ceiling height, insulation and sun exposure all affect the right size for your room. Your aircon installer calculates the exact capacity, your electrician uses that figure to select the correct cable and circuit breaker.

Can My Switchboard Handle a New Air Conditioner?

This is the question most homeowners forget to ask before booking. If your switchboard is full, installation can't proceed until a new circuit position is freed up or created, either by removing a spare circuit or upgrading to a larger board.

Older Sydney homes built before the 1990s often have smaller switchboards with six or eight circuit positions. If you've added an induction cooktop, EV charger or other high draw appliance in recent years, you may have fewer spare slots than you expect.

Signs your switchboard may need attention before installation:

• It uses ceramic or rewirable fuses, not circuit breakers

• There are no spare circuit breaker positions

• It doesn't have safety switches on every circuit

• The board feels warm to touch or looks corroded

A licensed electrician will assess this before quoting on the circuit. If you're noticing other symptoms too, like flickering lights or a board that feels warm, it's worth a broader fault finding visit alongside the aircon circuit assessment. If an upgrade is needed, it can often be done on the same day as the split system installation, reducing overall disruption.

How High Demand Electrical Helps

High Demand Electrical handles the electrical side of split system installations across Sydney, dedicated circuits, isolator switches, switchboard checks and compliance certificates. We work alongside your air conditioning installer or coordinate the full job on your behalf, and we're a licensed local team, not a call centre, so the person who quotes the job is the person who does it.

Split System Electrical FAQs (Sydney)

Does a split system need its own circuit?

Yes. AS/NZS 3000 and good practice both call for a dedicated circuit for a fixed air conditioning unit, so it isn't sharing a breaker with lights or power points. This prevents nuisance tripping and protects other appliances on the board.

Can my air conditioning installer do the electrical work too?

Only if they also hold an electrical licence. Many installers focus on the refrigerant and mechanical side and will refer you to a licensed electrician for the wiring, isolator switch and compliance certificate.

What if my switchboard needs upgrading first?

It's common in older homes. Our switchboard upgrades guide covers what's involved, and in many cases the upgrade and the new circuit can be done in the same visit.

How long does the electrical work take?

A straightforward dedicated circuit and isolator switch is usually a few hours' work. If a switchboard upgrade is needed as well, allow a full day.

Book the Electrical Side of Your Split System Installation

If you're having a new split system installed and need the wiring, isolator switch and compliance certificate handled properly, call Chris on 0402 559 777 or get in touch for a quote. We'll confirm your switchboard's capacity and give you a clear price after a quick assessment, no hidden costs.