AC Breaker Size Guide Pakistan — For Air Conditioners, Hybrid Inverters & On-Grid Solar (2026)
Updated: May 2026 · CNC Electric Pakistan
AC Breaker Size for AC, Inverter & Solar — Pakistan Quick Answer (May 2026)
For a typical Pakistani 1.5 ton inverter AC (running on WAPDA or solar), use a 1P 20A Curve C MCB on 2.5 mm² cable. For 2 ton AC with high inrush, upsize to 1P 32A on 4.0 mm² cable. For hybrid solar inverter feeding multiple ACs, use a 2P 40A or 63A MCB at the inverter AC output. Always: breaker amp rating must NEVER exceed cable safe current — undersizing the cable is a fire hazard, not the breaker.
Read also: AC Breaker Collection · AC Breaker Tripping Fixes
Choosing the right ac breaker and correct mcb size is one of the most practical electrical decisions in a Pakistani home, office, shop, or solar installation. A breaker that is too small nuisance-trips during compressor start or inverter surge, and a breaker that is too large allows cable overheating before protection operates. This guide covers the three use cases that matter most in Pakistan: air conditioners, hybrid solar inverters, and on-grid solar inverters. It is written for real WAPDA conditions, load shedding reality, 220V single-phase systems, and 380V three-phase systems that electricians deal with every day.
The goal here is simple: size the breaker from current, match it with the right cable, use the correct pole configuration, and avoid the common shortcuts that create hidden faults. For readers who want to compare product options, see circuit breakers, AC breakers, DC breakers, RCCB/RCBO, and SPD protection. If you need a broader quick-reference chart, also read the MCB size chart for Pakistan, the solar DB box guide, the types of circuit breakers guide, and the trip curves guide.
AC Breaker Size for Air Conditioners in Pakistan
The most searched question is simple: what breaker is correct for a 1 ton, 1.5 ton, or 2 ton AC? In practice, the answer depends on whether the unit is inverter or non-inverter, and whether the electrician has given the AC its own dedicated circuit. Most branded units in Pakistan from Gree, Haier, Orient, Dawlance, Kenwood, Pel, Changhong Ruba, TCL, Samsung, and LG run comfortably on a correctly sized C-curve MCB with proper cable. The mistake is not the breaker brand. The mistake is usually undersized cable, a B-curve breaker, shared wiring with lights or sockets, or random oversizing to stop tripping.
AC compressors pull a high starting current for a short time. That is why C-curve MCBs are the standard choice. A B-curve trips too quickly when a compressor starts, especially on low WAPDA voltage or long cable runs. Inverter ACs usually have lower inrush than fixed-speed units, but they still need correct protection and wire sizing. Pakistani builders often pull 1.5mm cable everywhere because it is cheap and familiar. That is acceptable only for small loads. Once tonnage rises, current and voltage drop rise with it. A breaker cannot fix a weak cable.
| AC Size | Type | Running Current | Starting Current (Inrush) | Recommended MCB | Wire Size | Notes |
|---|---|---|---|---|---|---|
| 0.75 ton | Non-inverter | 3-4A | 15-20A | 10A C-curve 1P | 1.5mm² | Light duty |
| 1 ton | Non-inverter | 5-6A | 20-25A | 16A C-curve 1P | 1.5mm² | Most common |
| 1.5 ton | Non-inverter | 7-8A | 25-35A | 20A C-curve 1P | 2.5mm² | Standard home |
| 1.5 ton | Inverter AC | 5-7A | 15-25A | 16A C-curve 1P | 2.5mm² | Lower inrush |
| 2 ton | Non-inverter | 9-10A | 30-45A | 25A C-curve 1P | 4mm² | Heavy |
| 2 ton | Inverter AC | 7-9A | 20-30A | 20A C-curve 1P | 2.5mm² | Lower draw |
| 2.5 ton | Non-inverter | 11-13A | 40-55A | 32A C-curve 1P | 4mm² | Commercial |
| 3 ton | Non-inverter | 14-16A | 50-65A | 40A C-curve 1P | 6mm² | Large commercial |
| 5 ton | 3-phase | 8-10A per phase | 30-40A per phase | 20A C-curve 3P | 4mm² | Industrial/commercial |
A dedicated AC circuit matters because compressors hate weak supply. If the same breaker line feeds lights, sockets, irons, or water pumps, voltage dips rise during start-up and nuisance tripping becomes normal. A dedicated circuit also makes fault tracing easier. When an AC trips its own breaker, the electrician knows exactly where to check: cable insulation, terminal tightening, compressor current, or outdoor unit condition. On shared circuits, one fault hides another.
Wire size is just as important as the breaker. A 20A MCB on 1.5mm cable for a 1.5 ton AC is bad practice. The breaker may tolerate the load while the cable warms up over time, especially in hot ceilings, PVC conduit, or bundled runs. In Lahore or Karachi summer, ambient temperature makes bad installation worse. When an AC breaker trips often, do not assume the breaker is poor quality. Check three things first: actual running current, trip curve, and cable size. In many houses the correct fix is not a bigger breaker; it is a proper 2.5mm or 4mm dedicated line with clean terminations.
| Practical AC Sizing Rule | What to Do |
|---|---|
| 1 ton or smaller room AC | 16A C-curve with healthy 1.5mm cable or better, dedicated line preferred |
| 1.5 ton inverter AC | 16A C-curve with 2.5mm cable gives cleaner performance than builder-grade mixed wiring |
| 1.5 ton non-inverter AC | 20A C-curve with 2.5mm cable on dedicated circuit |
| 2 ton class | 20A to 25A C-curve depending on type, with 2.5mm to 4mm cable |
| Repeated breaker trips | Measure current, confirm C-curve, inspect cable and voltage drop before upsizing |
MCB Size for Hybrid Solar Inverters — Input and Output
Hybrid inverters are where many Pakistani installations go wrong because the inverter has two AC protection points, not one. The AC input MCB sits between WAPDA and the inverter and protects the inverter from grid-side faults or isolation events. The AC output MCB sits between inverter and loads distribution and protects the load side supplied by the inverter. On battery-based systems, both sides matter because power flow changes with charging, bypass, backup mode, and grid return.
Single-phase hybrid inverters should normally use 2-pole MCBs so both line and neutral are switched and isolated together. Three-phase hybrids should normally use 4-pole MCBs. For this application, C-curve is the right default because it handles normal transformer and power electronics behavior without the unnecessary looseness of D-curve. A 63A breaker on a 5kW hybrid inverter is not “heavy duty”; it is dangerous oversizing. The breaker stops being meaningful protection and the cable becomes the weak fuse. Output side safety also needs an RCCB or RCBO where required by installation design.
| Inverter Brand | Model | Capacity | AC Input Current | Input MCB Size | AC Output Current | Output MCB Size | DC Breaker Size |
|---|---|---|---|---|---|---|---|
| Solis | S6-EH1P(3.6-6)K-H-US | 5kW | 25A | 32A 2P C-curve | 25A | 32A 2P C-curve | 32A 2P 500V DC |
| Solis | S6-EH3P(5-10)K-H | 10kW | 16A/phase | 20A 4P C-curve | 16A/phase | 20A 4P C-curve | 32A 2P 1000V DC |
| Growatt | SPH 5000TL BL-UP | 5kW | 25A | 32A 2P C-curve | 25A | 32A 2P C-curve | 32A 2P 500V DC |
| Growatt | SPH 10000TL3 BH-UP | 10kW | 16A/phase | 20A 4P C-curve | 16A/phase | 20A 4P C-curve | 32A 2P 1000V DC |
| Huawei | SUN2000-5KTL-M1 | 5kW | 25A | 32A 2P C-curve | 25A | 32A 2P C-curve | 25A 2P 600V DC |
| Huawei | SUN2000-10KTL-M1 | 10kW | 16A/phase | 20A 4P C-curve | 16A/phase | 20A 4P C-curve | 25A 2P 1000V DC |
| Goodwe | GW5048-EM | 5kW | 25A | 32A 2P C-curve | 25A | 32A 2P C-curve | 32A 2P 500V DC |
| Fronius | Symo GEN24 5.0 Plus | 5kW | 25A | 32A 2P C-curve | 25A | 32A 2P C-curve | 25A 2P 600V DC |
| ZRSolar | ZR-5KH | 5kW | 25A | 32A 2P C-curve | 25A | 32A 2P C-curve | 32A 2P 500V DC |
| Voltronic | Axpert MAX | 5kW | 25A | 32A 2P C-curve | 25A | 32A 2P C-curve | 32A 2P 500V DC |
| Infini | InfiniSolar V 5kW | 5kW | 25A | 32A 2P C-curve | 25A | 32A 2P C-curve | 32A 2P 500V DC |
| Tesla | Powerwall + | 5kW | 25A | 32A 2P C-curve | 25A | 32A 2P C-curve | N/A (DC-coupled) |
In a clean hybrid installation, the grid input MCB, inverter output MCB, DC breaker, and surge protection all sit inside a properly planned AC/DC box layout. This is why the solar DB guide matters. Protection is a system, not a single device. If the inverter is 5kW single-phase, 32A 2-pole C-curve is a very common practical size for both input and output positions. If the inverter is 10kW three-phase, 20A 4-pole often becomes the correct practical choice because current is distributed across phases.
| Hybrid Inverter Position | Purpose | Correct Practice |
|---|---|---|
| AC Input MCB | Protects inverter from grid-side faults and isolates WAPDA input | 2P for single-phase, 4P for three-phase, C-curve |
| AC Output MCB | Protects load-side output supplied by inverter | Match inverter output current, do not oversize |
| RCCB/RCBO | Shock and earth leakage protection on output side | Add where required by load distribution design |
| DC Breaker | Isolates PV/battery DC side and protects DC circuit | Choose correct DC voltage class first, then current |
AC-Side MCB Size for On-Grid Solar Inverters
On-grid solar inverters are simpler than hybrids on the AC side because they usually need one main AC output protection point to the grid or net metering panel. There is no battery backup output path in the standard design, so sizing focuses on the inverter’s AC export current. In Pakistan, proper documentation matters because net metering files, protection diagrams, and approval packages are stronger when breaker sizing is correct and clearly shown. The inverter should never be connected with a random breaker pulled from shelf stock.
A good on-grid installation uses the correct AC breaker, correct DC isolator, and SPD on both AC and DC sides. For single-phase 5kW units, 32A 2-pole C-curve is common. As size increases into three-phase 10kW, 15kW, and 20kW ranges, pole count and conductor size change quickly. A zero-export controller does not remove the need for proper MCB sizing; it only manages export behavior. Protection still follows current and cable rules.
| Brand | Model | Capacity | AC Output Current | MCB Size | Poles | Wire Size |
|---|---|---|---|---|---|---|
| Solis | S6-GR1P(2.5-6)K | 5kW | 23A | 32A 2P C-curve | 2P | 4mm² |
| Solis | S6-GR3P(3-20)K | 10kW | 16A/phase | 20A 4P C-curve | 4P | 4mm² |
| Solis | S6-GR3P(3-20)K | 15kW | 24A/phase | 32A 4P C-curve | 4P | 6mm² |
| Solis | S6-GR3P(3-20)K | 20kW | 32A/phase | 40A 4P C-curve | 4P | 10mm² |
| Growatt | MIN 5000TL-X | 5kW | 23A | 32A 2P C-curve | 2P | 4mm² |
| Growatt | MOD 10KTL3-X | 10kW | 16A/phase | 20A 4P C-curve | 4P | 4mm² |
| Huawei | SUN2000-5KTL-L1 | 5kW | 25A | 32A 2P C-curve | 2P | 4mm² |
| Huawei | SUN2000-10KTL-M0 | 10kW | 16A/phase | 20A 4P C-curve | 4P | 4mm² |
| Canadian Solar | CSI-5K-T400 | 5kW | 23A | 32A 2P C-curve | 2P | 4mm² |
| Fronius | Primo 5.0-1 | 5kW | 23A | 32A 2P C-curve | 2P | 4mm² |
| SMA | Sunny Boy 5.0 | 5kW | 22A | 32A 2P C-curve | 2P | 4mm² |
| Goodwe | GW5000-NS | 5kW | 23A | 32A 2P C-curve | 2P | 4mm² |
| JA Solar | JAIH-5K | 5kW | 23A | 32A 2P C-curve | 2P | 4mm² |
| Longi | LR5-54HPH | 5kW | 23A | 32A 2P C-curve | 2P | 4mm² |
| ZRSolar | ZR-5KG | 5kW | 23A | 32A 2P C-curve | 2P | 4mm² |
| On-Grid Design Point | Correct Practice |
|---|---|
| AC output breaker | Choose from inverter AC output current, not panel wattage alone |
| Single-phase 5kW class | 32A 2P C-curve with 4mm² is a common practical combination |
| Three-phase 10kW class | 20A 4P C-curve with 4mm² per phase |
| SPDs | Use SPD on AC and DC sides, especially in exposed roof installations |
| Net metering file quality | Breaker, SPD, cable, and isolator details should match drawings and installed hardware |
DC Breaker Size for Solar Panel Strings
DC breaker sizing starts with two numbers: string open-circuit voltage and string short-circuit current. In Pakistani solar installations using 540W-class modules, current per string is often around 13A to 14A, while voltage rises with the number of panels in series. The biggest mistake is using a breaker with enough current rating but the wrong DC voltage class. A 500V DC breaker on a near-900V string is wrong even if the current is only 14A. DC arcs do not behave like AC arcs, so voltage rating matters first.
| Panels in String | String Voc (approx) | String Isc (approx) | DC Breaker | DC Breaker Voltage |
|---|---|---|---|---|
| 8 panels (540W) | ~380V | ~14A | 20A 2P | 500V DC |
| 10 panels (540W) | ~475V | ~14A | 20A 2P | 500V DC |
| 12 panels (540W) | ~570V | ~14A | 20A 2P | 800V DC |
| 14 panels (540W) | ~665V | ~14A | 20A 2P | 800V DC |
| 16 panels (540W) | ~760V | ~14A | 20A 2P | 1000V DC |
| 20 panels (540W) | ~950V | ~14A | 20A 2P | 1000V DC |
In simple terms, current decides the ampere class, while string voltage decides whether you need 500V, 800V, or 1000V DC hardware. On rooftops with long strings, cold weather voltage rise margin should be respected. This is also where DC breakers and DC SPD devices work together. The breaker isolates and interrupts. The SPD handles surge energy.
7 Common MCB Sizing Mistakes in Pakistan
Most field problems do not come from complicated design theory. They come from repeated shortcuts. The same mistakes show up in homes, plazas, workshops, and solar sites: wrong trip curve, wrong poles, wrong cable, missing earth leakage protection, and no surge protection. When those errors combine with low WAPDA voltage, generator changeover, or roof heat, the system becomes unstable.
| Mistake | Why It Is Wrong | Correct Fix |
|---|---|---|
| Using B-curve MCB for AC or inverter | Trips too fast on inrush or startup conditions | Use C-curve for these applications |
| Oversizing MCB | Cable heats before breaker trips | Choose breaker from actual current and cable |
| Using 1-pole MCB on inverter | Neutral remains connected, isolation is incomplete | Use 2P single-phase or 4P three-phase |
| No RCCB on inverter output | Shock protection is incomplete | Add RCCB/RCBO where output distribution requires it |
| Sharing AC circuit with lights | Voltage drop and nuisance tripping rise | Give AC a dedicated circuit |
| Wrong DC breaker voltage rating | DC arc interruption becomes unsafe | Match breaker to actual string voltage class |
| No SPD on AC or DC side | Surge energy reaches inverter, DB, or appliances | Add correct SPD on both sides where needed |
- Using B-curve on AC compressors and inverter circuits instead of C-curve.
- Putting a 63A breaker on a 5kW inverter because “bigger is safer.” It is not.
- Switching only phase on inverter circuits and leaving neutral permanently tied.
- Skipping RCCB/RCBO because the system already has an MCB.
- Running ACs on mixed house wiring meant for sockets and lights.
- Installing a 500V DC breaker on a high-voltage string near 800V to 1000V.
- Ignoring SPD on rooftops and in areas with unstable supply and switching transients.
Frequently Asked Questions
| Question | Answer |
|---|---|
| What size MCB for 1.5 ton AC in Pakistan? | Usually 20A C-curve for non-inverter, 16A C-curve for inverter AC, with proper dedicated cable. |
| What size MCB for 5kW solar inverter? | A 32A C-curve is a common practical size for single-phase 5kW inverter AC circuits. |
| Do I need input and output MCB on hybrid inverter? | Yes. Hybrid inverters normally need both AC input and AC output protection. |
| Can I use B-curve MCB for air conditioner? | No. C-curve is the normal choice because AC compressors have startup inrush. |
| What size wire for 2 ton AC? | Usually 2.5mm² to 4mm² depending on type, run length, and installation conditions. |
| What MCB for 10kW 3-phase inverter? | A 20A 4-pole C-curve is a common reference size for many 10kW three-phase units. |
| Is RCCB required on inverter output? | Yes, where output-side earth leakage protection is required by system design. |
| What size DC breaker for solar panels? | Commonly 20A, but voltage class must match actual string Voc first. |
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Disclaimer: The MCB sizes listed in this guide are based on typical inverter specifications and standard electrical practice. Always verify the exact current ratings from the manufacturer's datasheet for your specific model and firmware version. Cable sizing should account for installation method, ambient temperature, and cable run length. Consult a qualified electrician for site-specific requirements.
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