Dan Luckow Electric




Molded Case Circuit Breakers


Call us at 1-800-237-4965 for price and availability or contact us.

We inventory all major brands of circuit breakers from 1amp to 5000amp. Molded Case Circuit Breakers

Circuit Breakers

A circuit breaker is an electrical switched which is developed to automatically project an electrical circuit from getting damaged due to short circuit or overload. It was designed to interrupt current flow on the detection of a faulty condition. The circuit breaker is different from a fuse in the sense that a fuse only works once after which it must be replaced. Circuit breakers on the other hand can resume its normal operation again once it is reset which can be achieved automatically or manually.

The size of a circuit breaker in most cases is dependent on the size of the appliance it is protecting based on the voltage it is to receive. Small circuit breakers are mostly used to protect individual household appliance and there are also large circuit breakers used to protect high voltage circuits that has the capability to power a full city.

Thomas Edison described an early type of circuit breaker in a patent application submitted in 1879. His commercial power distribution system was created to reduce or stop the effects of overloads and accidental short-circuits on circuit wiring through the use of fuses. Brown, Boveri and Cie however patented a new type of circuit breaker similar to the modern ones in 1924. The predecessors of the thermal-magnetic breaker in modern types known as DeutschesReichspatent were however created by Hugo Stotz and are still currently used in household load centers.

While circuit breaker systems details could vary based on the type of circuit breaker, voltage class and current rating, most of their other features operate in a common way. For the circuit breaker to be activated, it must detect a faulty condition. The faulty condition for low voltage circuit breakers are usually observed in the breaker enclosure, while the circuit breakers for high voltages are usually sensed and operated by protective relay pilot devices.

A separate battery is usually used to energize the trip solenoid that operates the latch. Some high-voltage circuit breakers however have protective relays, an internal control power source as well as current transformers. The circuit breaker opens to interrupt the flow of current once it detects a fault. The contacts are separated by energy, which is stored mechanically inside the breaker. Furthermore, some of the energy needed can also be gotten from the faulty current. While big circuit breaker systems make use of solenoids to trip off their mechanism and are able to restore energy though electric motors, smaller circuit breakers can be operated manually.

The contacts of the circuit breakers made from copper alloys, silver alloys, copper and other highly conductive materials must have the ability to work without getting heated excessively. It must also have the ability to endure the heat produced from the arc when it is interrupting the circuit. The process of interrupting the current could lead to the erosion of the contact material caused by arcing which in turn could have a negative effect on the length of the service life of the contacts. It is however possible to change the contacts of high voltage circuit breakers. The arc is caused by the interruption of current. The circuit breaker must however have the ability to endure, cool and extinguish the arch in a controlled way.

Circuit breakers are classified by their features which include interrupting type, structural features, voltage class and construction types. Some types of circuit breakers include magnetic circuit breakers, low-voltage circuit breakers, common trip breakers, thermal magnetic circuit breakers, high-voltage circuit breakers, medium-voltage circuit breakers, disconnecting circuit breaker, Sulfur hexafluoride high-voltage circuit breakers, earth leakage circuit breaker, carbon dioxide high-voltage circuit breakers, residual-current device, residual current breaker, recloser and polyswitch.

The major importance of circuit breakers is that they help to protect our electrical appliances from getting damaged by cutting off power supply.

Give us a call 24/7/365 and talk to our dedicated staff so we can get you the Molded Case Circuit Breakers you are looking for. 

Call 1-800-237-4965