Additionally, dirt can conduct electricity and cause a fault internally. Cleaningĭirt accumulated over time, can cause the components of the MCCB to deteriorate. If yours can be opened, take a look at its internal components. There are MCCBs that are sealed at the factory and others that can be opened.
Signs of overheating such as insulation and casing cracks or deformed contacts. Electric arcing indicated by casing or contact burns. Some of the signs that indicate damage include the following: This simply means checking for any signs that the MCCB has been damaged. Testing as explained in the section above. Some of the maintenance procedures necessary include the following: It is important to periodically provide maintenance for your molded case circuit breakers if they are to provide reliable protection. Magnetic protection tends to be instant and these can be handled well by the application. The pulses need to be very short since a fault can be very dangerous. Here you would want to simulate a fault by sending pulses of current that are very high. If it doesn’t then it is failing in thermal protection. 
Ideally, the breaker should trip correctly. This is where you use an over-current about 300 percent above the rated value. It is a two-part test which is conducted in the following sequence: You want to carry out this test last since the MCCB will heat up due to the high current. You will need to simulate a fault or overcurrent and then observe how the MCCB responds. You will need to test the resistance of electrical contact and then compare your findings with the manufacturer’s recommendations. Usually, this is a rather low value because the MCCB needs to allow current to pass through even when it has a low voltage. If the insulation resistance is found to be lower than the manufacturers’ recommended value, then the protection is not adequate. It requires you to disconnect the MCCB so that you can test the insulation across the load terminals, supply terminals and between phases. This test is done to ensure that you get reliable protection. Testing MCCBs Testing Insulation Resistance MCCBs, even though they are known to be used with high current applications can also be used with low current ones.
Adjustable trip settings for applications with low currents. Inrush current may need to be adjusted, providing the necessary overload protection without tripping. If the currents they draw are very high, MCCB protection becomes a necessity to reduce currents.Įlectric motors also need to be adequately protected and MCCBs do this work very well. These are used to correct power factors in industrial and commercial electrical systems. It is possible to have some welding applications that draw very high currents thus needing MCCBs since miniature circuit breakers cannot handle the high currents. MCCBs come in handy in both the situations. In some instances, you may also have additional circuits that will need trip settings. If you are using feeder circuits to distribute electric current, they can carry hundreds of amps. MCCBs, which can handle the current ratings, provide the protection needed. They usually produce hundreds of amps in output and require expensive gen-sets. Various MCCB Circuit Breakers Based on Applicationsĭue to the fact that they can handle especially high currents, molded case circuit breakers are often used with applications that are heavy duty. The on and off function can be used to switch the circuit on or off for repairs and replacements. They protect in the event of an overload where the current is higher than the rated value and lasts a longer time than normal. They offer protection in case of electrical faults by immediately interrupting a current that is extremely high due to a line fault or a short circuit. They are also used with frequencies that are 50 and 60 Hz and have the following 3 functions: 
MCCBs, as they are commonly known, have adjustable trip settings and can hold as much as 2,500 amps in current ratings.
Simply put, these are electrical protection gadgets that can be used with a wide range of voltages.
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