Low voltage Moulded case circuit breakers with Factory Price

An MCCB is a low-voltage protective device whose current-interruption components are housed in a solid moulded plastic case. It provides overload and short-circuit protection for higher-current circuits than an MCB can handle, typically from 16 A up to several hundred or even thousands of amps.

It uses a thermal-magnetic trip (or an electronic trip unit): a bimetal strip bends slowly under sustained overload (inverse-time delay), while a magnetic solenoid or electronic sensor trips instantly on a short circuit. When tripped, the contacts open and an arc chute splits and cools the arc until the fault current is safely interrupted.

An MCB is small, DIN-rail mountable, up to about 63–125 A, with fixed trip curves and limited breaking capacity. An MCCB handles much higher currents (often 100–1600 A+), offers higher breaking capacity, and commonly provides adjustable trip settings and field interchangeable accessories, making it suitable for main switchgear and feeders.

Adjustable trip lets the installer set the overload (long-time) and short-circuit (short-time/instantaneous) thresholds to match the load and to coordinate with downstream devices. MCBs have fixed factory trip curves, while adjustable MCCBs allow engineers to tune protection selectivity across a distribution system.

Low-voltage MCCBs are offered in a wide range — commonly 16 A, 32 A, 63 A, 100 A, 160 A, 250 A, 400 A, 630 A, 800 A, 1000 A, and up to 1600–2500 A for larger frames. The frame size and the rated current (In) are chosen together so the breaker can carry the load and coordinate with cables and downstream breakers.

They are typically mounted in a distribution board or switchgear enclosure, either by bolts to a mounting plate or on a DIN rail for smaller frames. Busbars or rated cables connect line and load terminals, and accessories such as shunt trips, undervoltage releases, and auxiliary contacts can be field-fitted for remote tripping and status signaling.

Low-voltage MCCBs are built and tested to IEC 60947-2 (low-voltage switchgear and controlgear — circuit breakers). This standard defines rated operational voltage (Ue), rated current (In), ultimate breaking capacity (Icu), service short-circuit breaking capacity (Ics), and the trip characteristics that define protection performance.

MCCBs are used as main breakers and feeder protection in industrial panels, commercial buildings, machine centers, generator and capacitor banks, HVAC and pump installations, and as incoming protection for distribution boards. They sit upstream of MCB branch circuits, forming a coordinated protection chain.

Choose In to be equal to or just above the full-load current, with a breaking capacity (Icu/Ics) greater than the prospective short-circuit current at that point in the system. Select the trip type (thermal-magnetic vs. electronic) and adjustability based on coordination requirements, and verify the number of poles (2P/3P/4P) matches the system.

Inspect connections and busbar torque periodically, check for overheating or arc marks, and exercise the operating handle to keep the mechanism free. Electronic trip units should be tested with primary-current injection where required by maintenance schedules. A breaker that has interrupted a major fault should be inspected or replaced by a qualified electrician before returning to service.