Short answer: Most split system air conditioners should be on a dedicated circuit, and many manufacturers require one, especially for larger units. Small units may be designed to plug into a standard power point, but larger splits and all ducted systems are normally hardwired, with an isolator near the outdoor unit. In NSW the refrigerant work needs an ARCtick-licensed technician, and the electrical work needs an appropriately licensed person.
Buying a split system is easy. Getting it installed properly means two trades working together: refrigeration and electrical. One of the first questions to settle is whether the unit needs its own circuit. Here’s how to tell, and what else the electrical side involves.
Plug-in vs hardwired
| Setup | Typical for | Electrical need |
|---|---|---|
| Plug-in | Some small split systems | A suitably rated power point near the indoor unit, if the manufacturer allows it |
| Hardwired, dedicated circuit | Most mid to large split systems | New circuit from the switchboard, protected by a safety switch |
| Hardwired, ducted | Ducted systems | Dedicated circuit, often larger; sometimes three-phase on very large systems |
| Multi-head split | One outdoor unit serving several rooms | Dedicated circuit sized for the outdoor unit |
The installation manual decides. It specifies the supply, circuit breaker rating and cable size. If it says a dedicated circuit, that’s what’s needed, even if a power point happens to be nearby.
Why a dedicated circuit matters
- Load: air conditioners draw a lot of current when the compressor runs. Sharing a circuit with a kettle or heater can cause nuisance trips or overheating.
- Start-up: compressors draw a surge when they start, which can trip a shared circuit.
- Protection: a dedicated circuit can be protected appropriately for the unit.
- Isolation: the technician can safely isolate the unit for servicing.
Isolators
An isolating switch is usually fitted near the outdoor unit so the system can be switched off safely for servicing. Isolators outdoors take a beating from the sun and rain. Faulty isolators are a known cause of safety switch trips and, in worse cases, overheating. If yours is cracked, discoloured or sticky, get it checked.
Who does what in NSW
- Refrigerant work (connecting pipework, charging gas) needs an ARCtick refrigerant handling licence. ARCtick’s licence types page explains the categories, including a restricted licence for single-head split systems.
- Electrical work needs the appropriate NSW licence. The NSW Government’s air-conditioning and refrigeration licence page explains how licensing applies to the different parts of an installation.
In practice, many air conditioning installers bring in a licensed electrician for the circuit and switchboard work. Whoever does it should give you a Certificate of Compliance for Electrical Work, which NSW requires within 7 days of testing, according to the NSW Government.
Check the switchboard first
A new circuit needs a spare space and safety switch protection. Older Inner West switchboards often can’t take one more circuit. Signs you might need an upgrade:
- ceramic fuses
- no spare spaces
- one safety switch covering everything
- frequent trips already
See signs you need a switchboard upgrade. If you’re adding several large loads, like air conditioning, induction and an EV charger, ask your electrician to look at the total load. A supply upgrade, such as moving to three-phase, is network work that needs a Level 2 Accredited Service Provider. Blue Link is not Level 2 accredited, but we’ll tell you if your plans point that way.
Planning tips for Inner West homes
- Outdoor unit location: narrow side passages and courtyards can limit airflow. Consider noise near bedrooms, yours and next door’s.
- Strata and heritage: apartments and heritage-listed homes may need approval for outdoor units. Check before you buy.
- Cable route: in terraces with no roof access, plan where the circuit will run.
- Pre-wire in renovations: if you’re renovating, run the circuit now even if the unit comes later.
- Surge protection: inverter air conditioners have sensitive electronics. See is surge protection worth it?
Installing a split system or ducted air? We run dedicated circuits, fit isolators and upgrade switchboards, and work with your air conditioning installer. See our air conditioning wiring in Marrickville or call 0421 772 661.
We wire air conditioners in Ashfield, Dulwich Hill, Petersham and nearby suburbs.
Frequently asked questions
Does a split system need a dedicated circuit?
Most do, and the manufacturer’s installation manual will say. Some small units can plug into a suitably rated power point if the manufacturer allows it.
Can my air conditioner installer do the electrical work?
Only if they hold the appropriate NSW electrical licence for that work. Many installers use a licensed electrician for the circuit and switchboard.
What is an air conditioner isolator?
A switch near the outdoor unit that lets technicians safely cut power for servicing. Isolators exposed to weather should be checked if they look damaged.
Will a new air conditioner need a switchboard upgrade?
Not always. It depends on spare space, safety switch protection and the overall load. Older boards with ceramic fuses often need upgrading.