Murray Molded Case Circuit Breakers

Murray Electrical Products has been around since 1899. The company has made a name for itself with its innovative designs and quality, reliable products. Murray designs and manufactures a variety of electrical products. They range from safety switches and multi-family meters, to AC disconnects and circuit breakers.

Murray Circuit Breakers

Electricity has become a basic human need since its invention in the late 18th century. The prevalence of electricity also means an increased demand for electrical circuits and circuit breakers.

The main function of circuit breakers is to protect circuits from melting under excess currents. They work by stopping the flow of electrical currents during high current surges. This is an especially important feature, as they prevent fires caused by faulty electrical circuit wirings.

Murray makes a variety of circuit protection products. One of these products is the Combination Arc Fault Circuit Interrupter, which works to prevent all types of an arc fault. Other circuit protection products include circuit breakers and surge arresters, which work to limit surges in voltages by transferring surges of currents to the ground.


About Molded Case Circuit breakers

Generally, most molded case circuit breakers are designed with an electrochemical trip unit that protects against excess current. This is done by combining two devices, one that detects changes in temperature, while the other detects changes in currents.

The trip unit inside molded case circuit breakers can be made up of a combination of different trip units. They serve to protect against thermal overloads, short circuits and ground faults.

Murray has many different designs of molded case circuit breakers. They can be found anywhere from domestic and commercial to industrial applications. You can find more information about some popular molded case circuit breakers from Murray below.


Murray’s BQ1100KM is a single pole, molded case circuit breaker. This means it can only be connected to a single circuit at a time.

The current rating for the BQ1100KM is 100 A, while its voltage rating is 277 V. This means it can only withstand voltages smaller than 277 V and currents smaller than 100 A.


Murray’s BQ125KM is also a single pole, molded case circuit breaker like its counterpart, the BQ1100KM. As a result, it only has the capacity to protect one circuit against current surges at a time.

At 277 V, the voltage rating for the BQ125KM is the same as the voltage rating for the BQ1100KM. This means it can handle all voltages smaller than 277 V. The BQ125KM is also rated for a current up to 25 A, meaning it is also a miniature circuit breaker capable of handling small currents less than 25 A.


Murray’s BQ245KM is another molded case circuit breaker. The BQ1100KM has two poles, so it can protect two different circuits from excess currents at the same time.

The BQ245KM also has a voltage rating of 277 V, which is the same as the BQ1100KM and the BQ125KM. At 45 A, its current rating falls between the BQ125KM and the BQ1100KM.


The ED220W by Murray is another molded case circuit breaker with two poles, like the BQ245KM. Therefore, it can be connected to two different circuits at the same time.

Like other circuit breakers in Murray’s ED line, the ED220W has a rather high amperage rating at 200 A. The ED220W also has a short circuit interrupting capacity of 10K. This means it can safely interrupt currents up to 10K.


The ED4160KP by Murray is a molded case circuit breaker. It is also a type HED breaker with a single pole, meaning it can only protect a single circuit from excess currents at a time.

The voltage rating on the ED4160 is 480 V, so it falls in the middle range of other Murray circuit breakers. Its current rating is 60 A, meaning it can withstand currents less than 60 A flowing through.


The ED4130 by Murray is another molded case circuit breakers with a single pole. Like its other single pole counterparts, the BQ1100KM, BQ125KM and BQ245KM, the ED4130 can only protect a single circuit from excess currents at a time.

At 30 A, the amperage rating for the ED4160 is also relatively small compared to other circuits in Murray’s product line. However, its voltage rating is 480 V, which is common for a typical circuit breaker.

Murray Electrical Products designs and manufactures a variety of molded case circuit breakers under its name. They work to accommodate the needs of both the commercial and industrial sectors. Some popular molded case circuit breakers made by Murray include the BQ125KM, which has a single pole, to the ED220W, which has two poles.