—Wiring and circuits
When an appliance needs its own circuit
Some appliances draw so much power, for so long, that they should not share a circuit with anything else.
Most sockets share circuits, which is fine for lamps, chargers and televisions. Appliances that draw heavy current for long periods — cookers and hobs, water heaters, some AC units, EV chargers, large heaters — are usually supplied by their own circuit, sized for that appliance and protected accordingly. Sharing a circuit with them is a common reason for breakers tripping when several things run together.
Wiring guides explain how circuits are put together and changed, so a quotation or a recommendation is easier to follow.
Whether an appliance needs a dedicated circuit depends on its rating and the manufacturer’s installation instructions, which are worth reading before buying. Adding a new circuit depends on space and capacity at the distribution board and on the total supply to the property, both of which are checked before the work is planned.
01In short
The points that matter most
Heavy, long loads
Cookers, water heaters, some AC units and EV chargers usually need their own circuit.
Read the instructions
Manufacturers state the supply their appliance needs.
Board and supply capacity
A new circuit needs space at the board and enough supply.
02Detail
What is assessed
Appliance rating
The power it draws and how it is connected — plug or fixed.
Cable and protection
A cable and protective device suited to the load and the route length.
Board space
Whether a spare way exists or the board needs changing.
03Checklist
Before buying a large appliance
Check the supply requirement
In the installation manual.
Check the board
A photo of the board shows whether there is space.
Plan the route
From the board to the appliance location.
04Questions
Questions people ask
- Can a cooker plug into a normal socket?
- Some smaller models can; many cookers and hobs need a dedicated fixed supply. The manual says which.
- Why does my kitchen trip when everything runs?
- Several high-power appliances on one circuit can exceed its rating.
- Does a new circuit need a new board?
- Only if there is no space or the board is unsuitable.
05Related
Related guides
- Earthing and bonding, explainedMore on the circuits behind the same problem.
- RCDs and RCBOs, explainedMore on the circuits behind the same problem.
- Surface or concealed wiringA related choice for the same kind of work.
- MCB or RCBOA related choice for the same kind of work.
This guide sits under electrical wiring. All topics are on the guides page.
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Planning a large appliance?
Send the appliance model and a photo of your board. We will tell you what supply it needs.