Most asked Miniature Circuit Breakers questions & answers (MCB FAQs)
- Raghotham n
- May 30, 2023
- 5 min read
Updated: Aug 26, 2023
What is MCB working principle?
A bimetallic strip and an electromagnetic coil are two essential parts of how a miniature circuit breaker operates. Here is a brief description of how an MCB works:
Bimetallic Strip: The bimetallic strip in the MCB is composed of two different metals that have been joined together and have various thermal expansion coefficients. This bimetallic strip is what the MCB’s electrical current passes through.
Thermal Protection: The bimetallic strip warms up due to the resistive heating effect in the case of an overload or excessive current. The strip bends because each metal in it expands at a different rate.
Tripping Mechanism: A tripping mechanism is activated as the bimetallic strip bends. Typically, the latch or spring-loaded component of this device is secured in place by the strip. The latch is released when the strip bends sufficiently to open the MCB contacts, cutting off the circuit.
Resetting the MCB: The MCB may need to be manually reset when the fault has been fixed or the overload removed. To do this, turn the switch back to its initial position. This restore the electrical connection and permits the electricity to flow once more.
In an MCB, the electromagnetic coil and bimetallic strip work together to provide magnetic and thermal protection. While the electromagnetic protection mechanism reacts quickly to short circuits and abrupt surges, the thermal protection mechanism reacts to continuous over-current. This operational principle guarantees the MCB’s capacity to safeguard the electrical circuit from harm and avert dangerous circumstance.
How many types of MCB?
There are mainly three types of MCB based on their tripping characteristics:
Type B MCB: Type B MCB are designed to protect circuits with resistive or slightly inductive loads. They have a magnetic tripping characteristic that quickly responds to short-circuits and overcurrents. Type B MCB typically trip at 3 to 5 times their rated current.
Type C MCB: Type C MCB are suitable for circuits with a mix of resistive and inductive loads. They have a slightly delayed magnetic tripping characteristic to accommodate higher inrush currents typically associated with motors, transformers, and other inductive devices. Type C MCB typically trip at 5 to 10 times their rated current.
Type D MCB: Type D MCB are designed to protect circuits with high inductive loads or equipment with significant inrush currents. They have a more pronounced delayed tripping characteristic to handle large inrush currents associated with equipment like large motors, welders, or transformers. Type D MCB typically trip at 10 to 20 times their rated current.
To ensure proper protection and reliable operation, it’s important to choose right type of MCB depending on the particular load characteristics and application needs of the circuit.
What is 6 amp mcb load capacity in watts?
To calculate the load capacity of a 6 Amp MCB in watts, you need to multiply the current rating by the voltage. To calculate the load capacity formula is:
Load Capacity (in watts) = Current (in amperes) x Voltage (in volts)
Just assuming a standard voltage of 230 volts which was common used in many residential and commercial settings, the load capacity of a 6 Amp MCB would be:
Load Capacity = 6 Amps x 230 volts = 1,380 watts or 1.38 kilowatts
So 6 Amp MCB can handle a load capacity of up to approximately 1,380 watts when connected to a 230-volt power supply. Keep in mind that this calculation is based on standard voltage, and actual voltages may vary depending on your location and electrical system.
16 Amp MCB Used for?
A 16 Amp MCB is commonly used for various electrical applications, including:
Residential Power Supply: In residential installation, 16 Amp MCB is often used for distributing power to circuits that have moderate current loads such as lighting circuits, general purpose outlets, smaller appliances and electronic devices.
Small Electronic Appliances and Equipment: 16 Amp MCB is suitable for protecting circuits that power smaller appliances like refrigerator, washing machine, dishwasher, microwave oven and other household equipment that do not have high power demands.
Lighting Circuits: 16 Amp MCB are commonly used to protect lighting circuits, particularly in residential and commercial settings where there is a moderate number of lights or lower power lighting fixtures.
Heating Ventilation and Air Conditioning Systems: In some cases, 16 Amp MCB may be used to protect circuits that power heating, ventilation, and air conditioning (HVAC) systems, especially for smaller residential or light commercial installations.
Small Industrial Applications: In smaller industrial setups or workshops, a 16 Amp MCB can be used to protect circuits that power smaller machinery, motor, pump or other equipment that have lower power requirements.
32 amp MCB used for?
A 32 Amp MCB is commonly used for various electrical applications, including:
Residential Power Distribution: In residential installations, a 32 Amp MCB is often used for distributing power to circuits that require higher current loads, such as kitchen appliance, electric water heater, air conditioning unit or heavy-duty power tools.
Commercial and Industrial Applications: In commercial and industrial settings, 32 Amp MCB can be used to protect circuits that power equipment like motor, pump, compressor, industrial machineries or larger electrical loads.
Lighting Circuits: 32 Amp MCB can also be used to protect lighting circuits, especially in cases where there is a significant number of lights or high-power lighting fixtures.
Single-Phase and Three-Phase Circuits: Depending on the electrical system, 32 Amp MCB can be used for both single-phase and three-phase circuits. In single-phase applications, it is often used for higher current loads, while in three-phase systems, it may protect individual circuits or equipment.
It’s important to note that the specific use of a 32 Amp MCB may vary depending on the electrical requirements and regulations of the specific installation. It is always recommended to consult with a qualified electrician or engineer to determine the appropriate MCB size and application based on your specific electrical needs.
What is 63 amp MCB load capacity in watts?
To measure the load capacity of 63 Amp MCB in watts, you need to multiply the current rating by the voltage & to calculate the load capacity, need to try with below given formula:
Load Capacity (in watts) = Current (in amperes) x Voltage (in volts)
Just assuming a standard voltage of 230 volts, the load capacity of a 63 Amp MCB would be:
Load Capacity = 63 Amps x 230 volts = 14,490 watts or 14.49 kilowatts
Hence, 63 Amp MCB can handle a load capacity of up to approximately 14,490 watts. when connected to a 230-volt power supply. Keep in mind that this calculation is based on standard voltage, and actual voltages may vary depending on your location and electrical system.
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