A circuit breaker isn't just a modern replacement for old fuses. Its job is to cut power before the wire overheats and the insulation catches fire. Get the rating wrong, and the breaker either trips over minor loads or, worse, fails to trip in time during a real overload.
Below is a simple way to size a breaker for household loads, typical values for common circuits, and the mistakes that show up most often in apartments and houses.
What a breaker actually protects
A breaker protects the wire, not the appliances. Its rating has to match the cable cross-section of that circuit: a thicker wire can safely carry more current. If you install a breaker with a higher rating than the wire can handle, the breaker won't trip in time, and the cable will overheat under a load the wire itself can't take.
So the first question isn't 'how powerful a breaker do I need' — it's 'what cross-section is already run on this circuit.' The rating follows from that.
How to calculate the load on a circuit
The calculation is simple: current (A) equals power (W) divided by voltage (220 V). For example, if a kitchen socket group has a kettle (2000 W), a microwave (1000 W), and a toaster (800 W), the combined load is 3800 W, roughly 17 A. You'd round up to the nearest standard rating with a small margin — typically 20 A, provided the wire on that circuit is rated for it.
The key is to size for a realistic scenario of several appliances running at once, not just the peak draw of a single device.
Typical ratings for household circuits
In practice, the same breaker ratings repeat from one apartment to the next. The table below gives approximate values, but the final choice always has to account for the actual wire cross-section and real load.
| Circuit | Typical load | Breaker rating |
|---|---|---|
| Lighting | up to 2 kW | 10 A (1.5 mm² wire) |
| Sockets (living rooms) | up to 3.5 kW | 16 A (2.5 mm² wire) |
| Kitchen socket group | up to 4.4 kW | 20 A (2.5–4 mm² wire) |
| Electric stove | up to 7 kW | 25–32 A (4–6 mm² wire) |
| Apartment main breaker | per design | 25–40 A |
Common mistakes when picking a rating
- Installing a breaker 'with margin' without checking the wire cross-section — that removes protection rather than adding safety.
- Using a single rating for the whole apartment instead of splitting circuits by purpose (lighting, sockets, heavy appliances separately).
- Ignoring the trip characteristic (B, C, D), which matters for inrush currents from things like a fridge compressor or a drill.
- Forgetting that a breaker doesn't protect against current leakage — that needs an RCD or an RCBO, not a higher-rated ordinary breaker.
When to call an electrician
If you're not sure of the wire cross-section on a circuit, don't have design documentation for the panel, or plan to connect heavy equipment (a stove, water heater, air conditioner), it's worth having an electrician do the sizing. A specialist checks the actual cable cross-section, the condition of the panel, and picks a rating that accounts for trip characteristics and selectivity with the main breaker. ELECTRIC ASTANA handles this kind of work 24/7, around the clock — call or message on WhatsApp for a consultation.