Circuit Breakers

Circuit Breakers

Whether the application is in your home or an industrial factory, breakers have become the standard. Until now you may have never had to learn more about them besides what to do when one is tripped, but let’s take a look at some of the details of a circuit breaker and how that will guide your purchase Starting with the basics, we know a circuit breaker is a device that will interrupt the flow of current in an electrical circuit. This interruption protects the surrounding electrical components and wiring from damage caused by either electrical overloads or short circuits. Great, now that we know that; let’s explore the next step in figuring out what kind of circuit breaker you’re looking for. The most common types of circuit breakers generally fall under two categories: MCCB (Molded Case Circuit Breaker) and MCB (Miniature Case Circuit Breaker) The easiest way of discerning the two breakers is to remember a MCCB will be suited for higher energy environments, like commercial factories, while the mini-breakers are meant for smaller environments with lower current ratings. Miniature Circuit Breaker (MCB) Rated current of no more than 100 Amps Trip current is usually not adjustable Thermal or thermal-magnetic operation Interruption current rating of up to 18,000 Amps (Depending on series and brand) Molded Case Circuit Breaker (MCCB) Rated current up to 1000-2,500 Amps (depending on series and brand) Trip current may be adjustable Thermal or thermal-magnetic operation Interruption current rating of up to 200,00 Amps (Depending on series and brand) Now that we’ve determined the sizing of your circuit breaker we should move on to protection ratings. Commonly circuit breakers will have one of these protection ratings: UL489, and UL1077. Wondering where UL508 protection ratings went? Find out here! UL489 Rated Circuit Breakers Considered to be the standard according to the National Electrical Code, UL489 listed circuit breakers are defined as “any listed circuit breaker that has an interrupting rating other than 5,000 Amps.” Overload tests are performed at 6x the current rating of the device or 150A minimum. Devices rated up to 600V and 6,000A are covered in this standard. Beyond overload protection the UL489 rated circuit breaker must offer short circuit protection, switching functionality, as well as disconnection function. Lastly, most UL489 devices are used in electrical distribution panels; therefore, the minimum current ratings available are seldom less than 15A.