MCB vs MCCB vs RCCB: Which Breaker Does What, and Where

Difference between MCB and MCCB: the short answer

The difference between an MCB and an MCCB is size and duty. An MCB, a miniature circuit breaker, protects the small circuits of a home or shop at up to about 63A or a little more. An MCCB, a moulded case circuit breaker, protects big feeders from roughly 16A up to well over a thousand amps, breaks much larger fault currents, and often has an adjustable trip.

Both do the same basic job. They switch a circuit on and off by hand, and they trip by themselves on overload and short circuit to protect the cable. What changes is how much current they carry, how big a fault they can safely break, and whether their trip setting can be changed.

In a typical Indian flat you will only meet MCBs. MCCBs live in the main panels of buildings, factories, malls and large motor or generator feeds, where an electrical consultant chooses them. We make MCBs, from 6A to 63A, at our works in Marol, Andheri East, Mumbai. We do not make MCCBs. This guide sets the two side by side, adds the RCCB, ELCB and RCBO, and shows where each belongs.

What is the full form of MCCB and MCB?

MCCB stands for moulded case circuit breaker and MCB for miniature circuit breaker; the moulded case is the larger insulated body that houses the bigger contacts and trip unit of an MCCB, while miniature describes the compact, rail-mounted body of an MCB that fits one way in a distribution board.

The other names you will meet on the same board:

MCB: miniature circuit breaker MCCB: moulded case circuit breaker RCCB: residual current circuit breaker ELCB: earth leakage circuit breaker RCBO: RCCB with overcurrent protection

Each is built to its own standard. MCBs for homes are commonly made to IS/IEC 60898-1, the standard printed on our VIYONA MCBs, while MCCBs are commonly built to IS/IEC 60947-2, the standard for industrial circuit breakers.

An MCB of the single pole kind takes one way in the box. An MCCB usually bolts into a panel of its own rather than clipping onto a home rail.

MCB vs MCCB: current rating and breaking capacity

As general practice, MCBs are made in current ratings from about 0.5A or 6A up to around 63A, with some ranges going to about 125A, while MCCBs commonly start around 16A and run to 1600A or more, and MCCBs are usually built to break much larger fault currents than an MCB can.

Breaking capacity is the largest short-circuit current a breaker can safely interrupt. Home MCBs are commonly 6 kA or 10 kA; our VIYONA 10 kA range is all 10 kA. MCCBs commonly start around 25 kA and go much higher, because a main panel close to a transformer can see far more fault current than a flat’s board.

Our 6 kA vs 10 kA MCB guide explains kA in detail.

Can you adjust the trip of an MCB or MCCB?

No, an MCB has a fixed trip: its current rating and its trip curve are set at the factory and cannot be changed, while many MCCBs let the electrician adjust the overload setting, and sometimes the short-circuit setting too, within a range, to match the cable and the load they protect.

That adjustability is one of the main reasons MCCBs are chosen for big feeders. One MCCB frame can be set to the load, and coordinated with the breakers below it so that a fault trips only the nearest one. Larger MCCBs can carry an electronic trip unit with finer settings.

An MCB’s fixed trip is a feature in a home: nobody can turn a 16A circuit into a 32A one with a screwdriver. If an MCB trips too often, the answer is to find out why, not to fit a bigger one. Our guide to an MCB tripping again and again covers the causes.

Where is an MCB used and where is an MCCB used?

An MCB is used on the final circuits of homes, shops and offices, such as lights, sockets, ACs and geysers, while an MCCB is used upstream on large feeders, such as a building’s main incomer, a floor or tower feed, a lift or pump panel, a generator changeover or an industrial motor.

Where you commonly find each, as general practice:

MCB: Flat distribution board Shop or office board AC and geyser circuits Sub-board per floor

MCCB: Building main panel Lift, pump and fire panels Generator changeover Factory motor feeds

In a housing society, the MCCB in the meter room feeds the building, and each flat’s own board then uses MCBs. A large home with a three phase supply still normally uses MCBs; see single phase vs three phase. For which MCB each home circuit needs, see which MCB for home.

MCB vs MCCB vs RCCB vs ELCB: what does each protect against?

An MCB and an MCCB both protect wiring from overload and short circuit, at small and large sizes respectively, while an RCCB and the older ELCB protect people from electric shock by tripping on current leaking to earth, so a safe home board pairs MCBs with an RCCB rather than choosing one or the other.

Put simply: MCB and MCCB protect cables and RCCB and ELCB protect people. An MCB’s trip is set in amps; an RCCB’s sensitivity in milliamps, commonly 30 mA for homes. A plain RCCB does not trip on overload, and an MCB does not trip on a small leak.

The ELCB is the old voltage-operated form of leakage protection; our RCCB vs ELCB guide explains why the current-operated RCCB replaced it. The isolator, which switches but never trips, is covered in isolator vs MCB.

At building scale the same split holds: an MCCB at the main panel may be paired with an earth-fault relay or a leakage device, chosen by the consultant.

MCB vs RCBO: what is the difference?

An MCB trips only on overload and short circuit, while an RCBO combines an MCB and an RCCB in one unit, so it also trips on earth leakage, giving one circuit both cable protection and shock protection without needing a separate RCCB in front of it.

The trade-off is cost and space against selectivity. With one RCCB over many MCBs, a leak on any circuit blacks out every circuit behind that RCCB. With an RCBO per circuit, only the faulty circuit goes off. For a fridge or a home office on its own circuit, that can be worth paying for.

Most Indian homes use the simpler layout: one RCCB, several MCBs. Either way, every circuit keeps overcurrent protection matched to its wire. If an RCCB, or the leakage side of an RCBO, keeps tripping, see RCCB tripping again and again.

VIYONA 401 is a single pole 10 kA MCB for 6 A to 32 A circuits with an MRP of ₹145, and VIYONA 411 is the double pole version at ₹350.

Can an MCB be used in place of an MCCB?

An MCB can be used in place of an MCCB only where the circuit’s current and its prospective fault current are both within the MCB’s ratings, which in practice means small loads far from the transformer; a big feeder or a main panel needs the higher current rating and breaking capacity of an MCCB.

Two numbers decide it. The first is the load current: if the feeder carries more than the top MCB rating, an MCB cannot be used. The second is the fault level: if a short circuit at that point could exceed the MCB’s kA rating, the MCB may fail to clear it safely.

The reverse question also comes up: should a home use an MCCB because it is “stronger”? Usually no. An MCCB set too high on a small circuit protects the cable less well than a correctly rated MCB.

A big pump or motor may need an MCB with a different trip curve, or a motor protection device; ask your electrician.

MCB vs MCCB price: why is an MCCB dearer?

An MCCB costs several times more than an MCB because it is a larger, heavier device built for far higher currents and fault levels, often with an adjustable or electronic trip, while an MCB is a compact, fixed-trip breaker made in large volumes for home circuits.

For a home board, the cost that matters is the MCB per circuit. Our VIYONA 10 kA MCBs by pole and rating:

VIYONA 433 is a 63 A four pole 10 kA MCB with an MRP of ₹1,035, the largest MCB we make. At 6A to 32A, single pole is ₹145. For the full list, see our 10 kA MCB range.

How to tell an MCB from an MCCB in a panel

To tell an MCB from an MCCB, look at the size and the face: an MCB is a narrow device about one module wide per pole that clips onto a rail, while an MCCB is a much larger moulded block, usually bolted in, often with a rating dial or trip unit and a frame size marked on it.

What to read on the face, with the panel closed:

Current rating, e.g. C16 or 63A Breaking capacity in kA or a boxed figure Standard: IEC 60898-1 or 60947-2 Adjust dial: MCCB

On our MCBs you will find IS/IEC 60898-1, the BIS licence CM/L-2544151 and the 10 kA rating. In a drawing, both are shown with the circuit breaker symbol, labelled with their rating; see our electrical symbols chart.

For a breaker in the switch board itself, our KEMPS TinyTrip modular MCBs are another option: the K225 single pole at ₹295 and the K226 double pole at ₹625, on our TinyTrip MCB page.

What we make: MCBs, not MCCBs

We make the VIYONA 10 kA range of miniature circuit breakers from 6A to 63A, in single, double, three and four pole, every one at 10 kA breaking capacity, plus isolators and MCB boxes, at our Mumbai works; we do not make MCCBs, RCCBs or RCBOs, which should come from a brand that lists them.

The range in one line: 401–403 single pole 411–413 double pole 422–423 three pole 432–433 four pole, from ₹145 to ₹1,035 MRP. Isolators run from ₹230 (442, 40A double pole) to ₹530 (462, 63A four pole).

To house them, the SPN white line MCB box runs from ₹380 to ₹950, and the double door board range includes TPN boards from ₹2,620; see SPN vs TPN distribution board.