A new split system or ducted unit that needs its own dedicated supply, or an existing air conditioner that trips the house every time it starts up. Air conditioners draw a serious amount of current on startup, and running one off a shared general power circuit is exactly why it keeps tripping.
Why this comes up
A new split system or ducted air conditioner being installed for the first time.
An existing unit sharing a circuit with too much else in the house.
Upgrading from a smaller unit to a larger one that needs more capacity.
Coordinating a new install with an air conditioning company’s own installer.
Adding a second or third split system to a property that already has one on a shared circuit.
A commercial or office fit-out needing multiple air conditioning circuits installed together.
How we handle it
Check the consumer unit capacity and main supply rating before anything else.
Run a dedicated circuit with correct isolation right at the unit.
Confirm the isolation switch location meets the requirement to be within sight of the outdoor unit.
Coordinate directly with your air conditioning installer on timing.
Test, certify, and label the new circuit clearly.
What to expect
Usually a day’s work, less if the consumer unit is close to the unit’s location. Best done before the air conditioning installer arrives so the supply is ready and waiting. If you’re installing multiple systems across a renovation or new build, we’ll plan the circuits together so the consumer unit has a clean, clearly labelled layout rather than being added to piecemeal.
What it costs
Depends on the run from the board to the unit and whether the consumer unit has a spare way available for the new circuit. Multiple units installed in the same visit generally cost less per circuit than spacing them out over separate call-outs.
Common questions
Does the air-con company handle this?
Usually not. Most require a qualified electrician to provide the dedicated circuit and isolation before they’ll connect the unit.
Why does my air conditioner trip the house?
It’s very likely sharing a circuit with too much else. Startup current on an air conditioner is high, and a shared circuit simply can’t handle it alongside other loads.
Can you install before the unit itself arrives?
Yes, and it is the better order of operations, having the circuit ready avoids delaying the air conditioning installer on the day.
Do bigger units need a bigger circuit?
Yes, and we size it correctly based on the specific unit’s rating, not just what the old one had.
What size cable does an air conditioner need?
Depends entirely on the unit’s rated current and the length of the run, so we size it to the specific unit rather than using a generic cable size.
Where does the isolation switch need to be?
Within sight of the outdoor unit, which is a safety requirement so anyone servicing the unit can isolate it themselves without needing to find the consumer unit.
Can I add a second air conditioner to the same circuit later?
Not recommended. Each unit really needs its own dedicated circuit sized to its own startup current.