Which MCB Does Your AC Need? 1, 1.5 and 2 Ton
The MCB for a 1.5 ton AC is typically 16A or 20A, on a circuit of its own. A 1 ton AC typically takes 16A, and a 2 ton AC 20A or 25A. Those are the ratings electricians commonly fit, but the one that counts is printed in your AC’s installation manual, which states the breaker the manufacturer expects. Below: why the numbers are what they are, single vs double pole, inverter vs fixed-speed, and the socket or switch that goes on the wall.
Key takeaways
- 1 ton AC — typically a 16A MCB.
- 1.5 ton AC — typically a 16A or 20A MCB.
- 2 ton AC — typically a 20A or 25A MCB.
- One AC, one MCB. Every AC gets its own circuit, commonly with a double pole MCB.
- ⚠ The AC’s installation manual wins. It states the breaker and cable; a licensed electrician fits them.
MCB for a 1.5 ton AC: the short answer
For a 1.5 ton AC, electricians commonly fit a 16A or 20A MCB on a circuit that feeds nothing else. For a 1 ton AC, 16A is typical. For a 2 ton AC, 20A or 25A. The MCB’s job is to protect the cable from overload and short circuit, so the exact rating follows the cable laid to the AC point and the current the AC draws.
Tonnage is the AC’s cooling capacity, not its electrical rating. Two 1.5 ton ACs can draw quite different currents depending on the model, the star rating and whether the compressor is inverter or fixed-speed. That is why the AC’s own installation manual, which lists the recommended breaker, is the final word.
We manufacture MCBs, and the switches and sockets that go on AC points, in Mumbai. This guide gives the typical ratings and the reasons behind them. The installation itself is a job for a licensed electrician.
Which MCB for 1 ton, 1.5 ton and 2 ton ACs?
The ratings below are what is commonly fitted for split and window ACs in Indian homes. 16A covers most 1 ton units, 16A–20A most 1.5 ton units, and 20A–25A most 2 ton units.
Typical MCB rating by AC size
Common practice for one AC per circuit. The AC’s installation manual states the breaker the manufacturer expects.
Where your AC’s manual gives a different figure, follow the manual. Where it gives a range, the electrician picks within it to match the cable.
| AC size | Typical MCB | Wall point | Our switch |
|---|---|---|---|
| 1 ton | 16A | 16A socket with switch | KEMPS K147 / VIZA V1246 (20A) |
| 1.5 ton | 16A or 20A | 16A socket or 20A switch | KEMPS K147 / VIZA V1246 (20A) |
| 2 ton | 20A or 25A | 32A DP switch | VIZA V1250 (32A DP) |
How much current does an AC draw?
Current is power divided by voltage. An AC’s nameplate lists its rated input power in watts. At 230 V, a 1,500 W input draws about 6.5 A and a 2,300 W input about 10 A while running.
Running current at 230 V for a given input power
Illustrative arithmetic (watts ÷ 230 V). Read the input power on your AC’s nameplate; it varies by model and star rating.
The MCB is rated well above that running current for two reasons. A fixed-speed compressor draws a much higher current for a moment as it starts, and an MCB rated too close to the running current would trip at every start. And the MCB protects the cable, so it is matched to the cable’s capacity rather than to the AC’s bare running figure.
Typically a 16A MCB on its own circuit.
The most common home AC, typically 16A or 20A.
Larger units, typically 20A or 25A, often with a DP switch.
The AC’s installation manual states the breaker; follow it.
Inverter vs fixed-speed AC: does the MCB change?
An inverter AC ramps its compressor up gradually, so it avoids the sharp starting surge of a fixed-speed (non-inverter) AC. In practice the MCB rating for the same tonnage is often the same, because it is set by the cable and the maximum load. What changes is the margin against nuisance tripping at start-up, which is smaller on a fixed-speed unit.
If an AC trips its MCB every time the compressor starts, do not simply fit a bigger MCB. That can mean the MCB is undersized for the unit, but it can also mean a failing compressor or a wiring fault. An electrician checks which.
Never upsize an AC’s MCB to stop tripping without checking the cable. A bigger MCB on the same wire lets the wire overheat before it trips.
Single pole or double pole MCB for an AC?
Many electricians fit a double pole (DP) MCB for each AC. A DP MCB breaks both phase and neutral, so the AC circuit is fully isolated when it is off, which is safer for the technician servicing the outdoor unit. A single pole (SP) MCB breaks the phase only and is also used.
We make the 10 kA MCB in single pole and double pole from 6A to 32A, which covers the 16A, 20A and 25A ratings used on AC circuits. Either way, the AC gets a circuit of its own in the distribution board.
One AC, one MCB. Two ACs on a shared circuit is the most common cause of an AC circuit tripping on a hot afternoon.
Socket or DP switch for the AC point?
The MCB sits in the distribution board. On the wall beside the AC there are two common arrangements. The first is a 16A socket with a switch, into which the AC’s plug goes. The second, common for larger units, is a 20A or 32A DP switch with the AC wired to it directly, with no plug at all.
We make both. For switches, the KEMPS 20 AX one-way switch (K147), the VIZA 20A one-way switch (V1246) and the VIZA 32A DP switch with indicator (V1250). The switch and socket ratings table lists every rating we make, and 6A vs 16A socket explains why an AC never goes on a 6A point.
The switch rating must be at least the MCB rating on that circuit. A 20A MCB feeding a 16A switch leaves the switch as the weak point.
Wire size for an AC circuit
The cable from the board to the AC point is sized by the electrician for the AC’s current and the length of the run, and the MCB is then chosen to protect that cable. That order matters: cable first, MCB second. An MCB chosen first and a cable fitted to whatever was on hand is how circuits overheat.
We do not give a cable size here, because it depends on the length of the run, how the cable is laid and the AC’s current, and it is fixed by the electrician under the wiring rules. What you can do is ask the question: which cable, which MCB, and why.
If the AC point was wired years ago for a smaller unit, have the cable checked before fitting a larger AC. A new AC on an old light-duty cable is a fire risk no MCB rating fixes.
Signs your AC MCB is wrong
Three signs point to a mismatch. Trips at start-up: the MCB may be undersized or the compressor may be struggling. Trips on hot afternoons: the circuit may be shared with other loads. Warm switch or socket: the point or its connection is overloaded or loose, and needs attention now.
Our guide on a switch getting hot or a socket sparking covers the last one in detail. In each case, an electrician checks the AC’s current, the cable and the MCB together rather than swapping one part.
Planning a home with several ACs
A 2BHK with an AC in each bedroom and one in the living room has three AC circuits, each with its own MCB, plus the incomer sized for all of them running together on a summer evening. That is the load your main MCB and sanctioned load must cover.
Plan the distribution board with spare ways for ACs added later. Our SPN white line MCB box comes in 2–4 up to 16–18 way. For every other circuit in the house, from lights to the geyser to the main line, read which MCB for home.
FAQs
Which MCB is used for a 1.5 ton AC?
Which MCB is used for a 1 ton AC?
Which MCB is used for a 2 ton AC?
Should an AC have a single pole or double pole MCB?
Can two ACs share one MCB?
Which socket is used for an AC?
Why buyers choose Vinayak Electricals
- 10 kA MCBs from 6A to 32A, single and double pole, made in Mumbai.
- Made to IS/IEC 60898-1, BIS licence CM/L-2544151.
- 20A switches (KEMPS K147, VIZA V1246) and a 32A DP switch (VIZA V1250) for AC points.
- MCB boxes and distribution boards with spare ways for more ACs.
- MRPs published openly in our catalogue.
- Over 30 years manufacturing electrical goods; ISO 9001:2015 certified.
