What size breaker for each circuit? Lighting, sockets, oven, air conditioning and EV charger

The Journal · Oct 28, 2026

What size breaker for each circuit? Lighting, sockets, oven, air conditioning and EV charger

Written by Engin Demirel · Electrical technician, master instructor · 12 years of experience

Short answer: A breaker is sized to the cable of the circuit, not to the appliance; the breaker protects the cable. In Turkish homes, lighting circuits typically use a 10 A breaker with 1.5 mm² cable and socket circuits a 16 A breaker with 2.5 mm² cable. Ovens, water heaters, air conditioners, washing machines and dishwashers get their own dedicated 16 A circuit. An electric hob usually needs 32 A on single phase or 3 × 16 A on three phase. Typical values for a wall-mounted EV charger are 32 A for 7.4 kW single phase, 3 × 16 A for 11 kW three phase and 3 × 32 A for 22 kW three phase. A 40 A breaker is rarely for a single appliance; it usually protects a main supply or a sub-panel fed with 10 mm² cable. Local wiring rules apply (BS 7671, IEC 60364 and national standards), and the final values are set by the design and a qualified electrician.

First, the maths: how many amps does it draw?

To find the current on a circuit, add up the power of the appliances and divide by the voltage:

Single phase (230 V): Current (A) = Power (W) ÷ 230
Three phase (400 V): Current (A) = Power (W) ÷ (1.73 × 400), i.e. roughly Power ÷ 692 per phase

Examples: a 2,000 W kettle draws 2,000 ÷ 230 ≈ 8.7 A. A 3,000 W water heater draws ≈ 13 A, so a 16 A breaker works and a 10 A one does not. An 11 kW three-phase EV charger draws 11,000 ÷ 692 ≈ 15.9 A per phase, which is why it pairs with 3 × 16 A.

Pick the next standard breaker rating above that current (6, 10, 16, 20, 25, 32, 40, 50, 63 A), then check that the cable can carry it. If the cable is too small, you do not downsize the breaker below the load, you upsize the cable.

Circuit by circuit (homes, typical values)

Lighting: 10 A – 1.5 mm². With LED, many fittings fit on one circuit; the limit is usually inrush current, not power.
General sockets: 16 A – 2.5 mm². Rooms are split over several socket circuits.
Kitchen worktop sockets: 16 A – 2.5 mm² on a separate circuit, because kettle, toaster and coffee machine run together.
Washing machine, dishwasher, tumble dryer: each on its own 16 A – 2.5 mm² circuit.
Water heater (2–3 kW): dedicated 16 A – 2.5 mm².
Built-in oven (about 2.5–3.6 kW): dedicated 16–20 A – 2.5 mm² (20 A may need 4 mm² depending on installation). Check the rating plate.
Electric or induction hob (often 7–7.5 kW): 32 A – 6 mm² on single phase, 3 × 16 A – 5 × 2.5 mm² on three phase, following the hob's wiring diagram.
Air conditioning: a dedicated 16 A – 2.5 mm² circuit per indoor unit, type C because of compressor starting current.
EV charging 3.7 kW (single phase 16 A): dedicated 16 A – 2.5 mm² (larger on long runs).
EV charging 7.4 kW (single phase): dedicated 32 A – 6 mm².
EV charging 11 kW (three phase): dedicated 3 × 16 A – 5 × 2.5 or 5 × 4 mm².
EV charging 22 kW (three phase): dedicated 3 × 32 A – 5 × 6 mm².
Garden and outdoor: separate circuit, 10 A (lighting) or 16 A (sockets); larger cable on long runs because of voltage drop.

These figures are for short and medium runs installed normally. For details see the cable size calculation guide. In some countries practice differs: in Germany lighting and sockets are often B16 on 1.5 mm², in France NF C 15-100 uses 16 A on 1.5 mm² for lighting and 16 or 20 A for socket circuits depending on the cable.

Why 16 A for sockets but 10 A for lighting?

A lighting circuit is wired in 1.5 mm² cable, which safely carries around 10 A. Sockets, however, feed hair dryers, heaters and irons above 2 kW, so they get 2.5 mm² cable and a 16 A breaker. Putting a 16 A breaker on 1.5 mm² lighting cable lets the cable overheat under overload.

Why does an EV charger need its own circuit?

A charger runs at full power for hours. A heater on a socket switches on and off for a few minutes, but a charging circuit carries the same current all night; so it has its own circuit, the cable is sized for that continuous load and it is protected by a residual current device. A 32 A single-phase charging circuit, together with the rest of the house, can exceed the supply capacity; then a capacity upgrade or a move to three phase is needed. If you are not sure which power to choose, the EV charger finder suggests one based on your car and your supply.

When do you use a 40 amp breaker?

40 A is rarely needed for one household appliance. Typical places:

Main breaker: the breaker after the meter is sized to the supply (contracted) capacity. For example a 9 kW single-phase supply gives 9,000 ÷ 230 ≈ 39 A, so 40 A.
Sub-panel feed: the supply to an outbuilding, garage or garden house; for 40 A the cable is usually 10 mm².
Residual current device: the 40 A on an RCD is not its trip value but the maximum current its contacts can carry. It must not be smaller than the breaker in front of it. In our EV charger installations in Bursa, a 40 A type A RCD, a 40 A breaker and a surge protection device are part of the installation.

It is normal that the circuit breakers in a panel add up to more than the main breaker; not everything runs at full power at once. But if the main breaker trips often, the supply capacity is too low.

Common mistakes

Replacing a tripping breaker with a bigger one: a 16 A breaker on a 10 A lighting circuit leaves the cable unprotected.
Plugging the oven and water heater into socket circuits: the circuit runs at its limit and plugs and sockets get hot.
Several big loads on one circuit: with air conditioner, heater and oven together, the breaker trips for a good reason.
Ignoring the number of poles: a three-phase appliance is protected by a 3-pole breaker; three separate single-pole breakers can leave two phases live when one trips.

The tripping curve (B or C) is a separate topic; see type B vs type C circuit breakers. Our shop carries Legrand XS4 single-phase and three-phase breakers from 6 A to 63 A with curves B and C and 4.5 kA breaking capacity.

Frequently asked questions

Where is a 16 amp breaker used?

In homes it protects socket circuits and dedicated circuits for washing machines, dishwashers, water heaters and air conditioners, usually with 2.5 mm² cable. An 11 kW three-phase EV charger circuit is typically 3 × 16 A as well.

Where is a 40 amp breaker used?

Mostly as the main breaker (depending on supply capacity) or to feed a sub-panel or outbuilding; the cable for 40 A is usually 10 mm². A single household appliance rarely needs it.

What size breaker for an oven?

Built-in ovens usually go on a dedicated 16 A or 20 A circuit. The value depends on the oven's power and rating plate, and the cable is sized to the breaker.

How many amps does an electric hob need?

A 7–7.5 kW hob draws about 32 A on single phase and needs 32 A with 6 mm² cable; on three phase it draws about 10–11 A per phase and 3 × 16 A is enough.

What size breaker for an EV charger?

Typically 32 A for 7.4 kW single phase, 3 × 16 A for 11 kW and 3 × 32 A for 22 kW three phase, always on a dedicated circuit. The final value follows the design and the charger's installation manual.

Can I put a 16 A breaker on a lighting circuit?

Not if it is wired in 1.5 mm² cable; the breaker protects the cable, and 1.5 mm² gets 10 A. 16 A is only possible if the circuit is wired in 2.5 mm².