Choose a circuit breaker for an air conditioner from the appliance nameplate, cable capacity, starting current and fault level. A C-curve breaker can help with compressor inrush, but it is not automatically the right answer for every AC.
The correct breaker is the smallest standard rating that can carry the air conditioner's design current without exceeding the cable's safe capacity, while still meeting the appliance instructions, starting-current behavior and local disconnection rules.
Do not select an AC breaker from BTU, horsepower or tonnage alone. Read the exact model's electrical label first. For a plug-in portable AC, follow its plug and socket instructions. For fixed equipment, use the manufacturer's minimum circuit ampacity and maximum overcurrent protection values when provided, then verify the cable, trip curve, poles and fault rating.
Midea's PortaSplit became a visible part of Europe's 2026 cooling rush, but its electrical data tells a more useful story than the sales headlines. Midea reports that more than 300,000 PortaSplit units have been sold across European markets since the product launched there in 2024.1
The official PortaSplit manual lists a 220-240V, 50Hz single-phase supply, 3.5kW rated cooling capacity and 10A maximum current. It also says to plug the unit directly into a wall socket and not use an extension cord, splitter or multi-plug adapter.2
This example does not mean that every 10A portable AC needs a C16 breaker, or that a homeowner should replace the breaker behind an existing socket. It means the electrician must compare the exact appliance instructions with the existing socket circuit, other loads on that circuit, conductor capacity and local rules. If those conditions are unknown, the safe next step is inspection, not a larger breaker.
A sound selection follows five linked checks. Skipping any one of them can produce a breaker that appears to work but no longer protects the cable or disconnects a fault quickly enough.
Record supply voltage, phase, rated input current, maximum current and any manufacturer-stated fuse or breaker value. On many North American fixed systems, also look for MCA (minimum circuit ampacity) and MOCP or MOP (maximum overcurrent protection). Do not substitute data from a similar BTU or tonnage model.
Use the manufacturer's declared current and installation method. A simple watts-divided-by-volts calculation can be a cross-check, but it does not replace nameplate current because compressor controls, power factor, inverter electronics, heating mode and test conditions affect actual demand.
The IEC-based relationship is IB ≤ In ≤ Iz: design current must not exceed breaker current, and breaker current must not exceed the conductor's permitted current. Cable material, cross-section, installation method, ambient temperature and grouping all change Iz.3
Compare the AC's declared or measured inrush with the breaker's time-current curve. C curve is commonly considered for motor loads, but modern inverter compressors may start differently. A curve with a higher instantaneous threshold must still meet automatic-disconnection and fault-loop requirements.
Match voltage and phase, then confirm that breaking capacity is at least the prospective short-circuit current at the board. Check local requirements for isolation and residual-current protection, including the type of RCD or RCBO suitable for the appliance electronics.
The curve letter describes the breaker's instantaneous magnetic response, not its normal amp rating. Under IEC 60898-type conventions, B and C have different instantaneous ranges; the exact D range can vary by product standard and manufacturer documentation, so the selected device's data sheet remains authoritative.4
| Curve | Typical instantaneous range | When it may fit | What must be checked |
|---|---|---|---|
| Type B | About 3-5 x In | Low-inrush loads and some inverter-driven appliances where manufacturer data permits | Actual startup behavior and nuisance-trip history |
| Type C | About 5-10 x In | Motor and compressor circuits with moderate inrush | Fault-loop impedance, disconnection time, cable protection and manufacturer instructions |
| Type D | Higher than C; consult product data | High-inrush equipment only when the system study supports it | Short-circuit current, coordination and local approval; rarely a default residential choice |
A less sensitive curve can delay fault clearing. A larger amp rating can leave the cable under-protected. Repeated tripping may also indicate a shared overloaded circuit, poor connection, damaged cord, failing compressor or supply-voltage problem.
An air conditioner breaker size chart is useful only when it directs you to the right source value. Cooling capacity helps size the AC for a room; it does not uniquely determine electrical current.
| AC type | Start with | Circuit decision | Do not size from |
|---|---|---|---|
| 230V plug-in portable AC | Manual, plug type, maximum current and socket rating | Verify the existing socket circuit and other connected loads; use direct wall connection when instructed | Watts or BTU alone |
| 115V portable or window AC | Manufacturer's electrical-requirements section | Some models require a separate circuit or time-delay protection; follow the exact manual | A similarly named 230V model |
| Fixed mini-split | Nameplate, installation manual, MCA and MOCP/MOP when supplied | Design the dedicated final circuit, isolation and protection to local rules | Indoor-unit current alone |
| Central AC or heat pump | Outdoor-unit nameplate and manufacturer overcurrent data | Coordinate conductor ampacity, breaker/fuse, disconnect and any auxiliary heat load | Tonnage, including the phrase "3-ton AC," by itself |
| Multiple AC units in one building | Each final circuit plus coincident feeder demand | Check submains, risers, busbars and main protection as a system | One apartment's breaker multiplied without a diversity study |
There is no safe universal answer. Two 10,000 BTU units can use different voltages, compressor technologies and input currents. One may be a 230V inverter model supplied with a regional plug; another may be a 115V unit whose manual requires an individual branch circuit. Use the exact electrical label and manual.
Tonnage describes cooling output, not branch-circuit current. Fixed 3-ton systems vary by efficiency, compressor design, voltage, phase and optional electric heat. Use the outdoor unit's MCA and MOCP/MOP values, where provided, and have the circuit designed to the applicable code.
For a single-phase load, dividing input watts by supply volts gives a rough current cross-check. It is not the final breaker calculation because the nameplate may already account for conditions the simple formula omits.
1,350 W / 230 V = 5.87 A
If the same appliance manual lists a 10A maximum current, use the manufacturer's declared electrical data when checking the circuit. Do not infer that 5.87A automatically calls for a particular breaker curve or rating.
This is also why the blanket "breaker equals 125 percent of rated current" rule should not be presented as a global sizing method. North American motor-compressor rules, European IEC-based wiring practices and manufacturer-marked MCA/MOCP values do not collapse into one universal multiplier.
A trip is a symptom, not permission to install a larger breaker. The timing of the trip helps narrow the cause, but internal appliance work and distribution-board testing belong with qualified technicians.
| When it trips | Possible causes | Safe next step |
|---|---|---|
| Immediately at startup | High inrush, short circuit, earth fault, damaged cord, unsuitable curve or appliance fault | Stop repeated resets; isolate the unit and have current and fault conditions tested |
| After several minutes | Sustained overload, shared circuit, weak connection, overheating conductor or compressor problem | Disconnect other loads and arrange inspection of the circuit and appliance |
| Only on very hot days | Long duty cycle, higher condensing pressure, voltage drop or coincident building demand | Check supply voltage, connections, ventilation and feeder loading |
| RCD or RCBO trips | Leakage current, moisture, damaged insulation or protection-type compatibility | Do not bypass residual-current protection; test the appliance and circuit |
The kA figure is the maximum prospective short-circuit current the breaker can interrupt under its specified conditions. It is not the current the AC consumes and it is not extra headroom for compressor inrush.
The breaker's rated breaking capacity must equal or exceed the prospective short-circuit current at its installation point.5 That value depends on the supply transformer, network impedance, conductor lengths and upstream coordination. An older building does not automatically need 10kA, and a newer building does not automatically make 6kA sufficient. Measure or calculate the fault level.
For panel builders and electrical distributors, GEYA offers B, C and D curve options across the miniature circuit breaker range. The correct variant is chosen after the circuit study, not from the appliance category alone.
For IEC/EN 60898-1 final-distribution applications where the calculated prospective fault current and project specification permit the selected breaking capacity.
For projects whose calculated fault level or specification requires higher breaking capacity, while retaining the required current rating and trip curve.
A product being available in C curve or 10kA does not make that configuration correct for a given air conditioner. Confirm current, cable, poles, voltage, inrush, fault level, disconnection time and local protection requirements together.
The PortaSplit boom also matters above the apartment distribution board. During a heatwave, many units can run at the same time. Each final circuit may be correctly protected while the shared riser, submain, busbar or service entrance approaches its limit.
Landlords, facility managers and panel builders should compare realistic coincident demand with feeder and busbar capacity. If the constraint sits upstream, the solution may involve load management, feeder work or coordinated MCCB protection, not a different MCB in one apartment.
No. C curve is commonly used where compressor or motor inrush would nuisance-trip a B curve, but the correct curve depends on manufacturer data, startup current, cable protection, fault-loop conditions and local rules. Some inverter units may operate correctly on another permitted curve.
Fixed split and central systems commonly require a dedicated circuit under their installation instructions and local rules. Plug-in portable units must follow their own manual and the existing socket-circuit limits. Even where a separate circuit is not explicitly required, sharing with another high-load appliance can overload the circuit.
Not without verifying conductor capacity, socket rating, installation method, fault protection and appliance instructions. Upsizing the breaker alone can remove protection from the cable and connected accessories. Find the cause of the trip first.
Follow the appliance manual. Midea's PortaSplit manual specifically says to plug directly into a wall socket and not use an extension cord, splitter or multi-plug adapter. Other models may carry similar restrictions.
They may use different supply voltages, compressor technologies, efficiency levels, heating functions and control electronics. BTU describes cooling capacity; the nameplate and manual describe the electrical load.
It is higher breaking capacity, but suitability depends on prospective short-circuit current at the installation point. It does not improve normal load capacity or solve compressor inrush by itself.
Send GEYA the supply voltage, load current, required poles, trip curve, prospective fault current and quantity. Our team can match the appropriate MCB configuration for your panel or distribution project.
Check Out The Full Catalog
Quick Info Exchange Helps Us Serve You Better
(Low-voltage and solar energy electrical components catalog)
