The Complete Guide to Buying a Circuit Breaker: Everything to Know

Did you know that modern circuit breakers have a life expectancy of 15 to 20 years? Some circuit breakers can last longer, but others have a shorter lifespan depending on the type you have.

You probably don’t pay attention to your circuit breaker until you need to, but do you know the age of your circuit breaker? If it is getting up there in years, it might be time to replace it.

Keep reading to learn factors to consider when buying a circuit breaker.

Voltage Rating

When buying a circuit breaker, you’ll need to check the voltage rating. The voltage capacity you need will have to meet your end application.

The highest voltage that can be applied across every end port is the overall voltage rating. The rating will also factor in the type of circuit breaker and how it is integrated into the system.


Frequencies higher than 120Hz will lead to the breaker derating. You should be looking for circuit breakers up to 600 amps that can apply to frequencies of 50-120Hz.

For projects where you need higher frequencies, components will need to be specifically calibrated. The quantity of deration depends on frame size, ampere rating, and current frequency.

The higher the ampere rating in a certain frame size, the greater the derating will be. There are a lot of options for circuit breakers with up to 600 amps and over 600 amps.

Maximum Interrupting Capacity

A circuit breaker provider should be honest about the maximum interrupting rating. This capacity is the higher amount of fault current that a breaker can interrupt without the system failing.

Determining this amount can be done at any time. The one rule when calculating circuit breaker features like this is that the interrupting capacity of the breaker must be equal to or more than the amount of fault current.

When you fail to apply the correct amount of interrupting capacity, damage will occur to the breaker.

Operating Conditions

Comparing circuit breaker costs involves having the end-user location in mind. The same goes when selecting a rcbo consumer unit based on operating conditions.

Some breakers are better suited for unforgiving environments. Keep these scenarios in mind when deciding what kind of circuit breaker to use:

  • High ambient temperature
  • Corrosion and moisture
  • High shock probability
  • Altitude
  • Resting position

For operating conditions that involve high temperatures, corrosion, moisture, and high shock probability, you’ll need a circuit breaker that can withstand those conditions.

Circuit breakers must be derated when used in areas where the altitude is over 6,000 feet. Most breakers can be mounted in any resting position but be sure this is the case with your breaker before purchasing.

Bay Power circuit breakers have different breakers for multiple operating conditions.

Buying a Circuit Breaker the Right Way

When buying a circuit breaker, there are a lot of things to keep in mind. Most importantly, you need to consider the application and end-user location.

If you know the uses for your circuit breaker, you can then move on to looking at voltage rating, frequency, maximum interrupting capacity, and operating conditions.

Use this guide to choose the perfect circuit breaker for your needs and don’t forget to come back to our website for more articles like this.