Low Voltage Circuit Breaker Selection Guide

What Do You Know About Low Voltage Circuit Breakers?

The circuit breaker is a static protective device that is used to protect electrical and electronic devices from voltage surges. A circuit breaker (CB) can break a circuit whenever a fault occurs and it can make a circuit whenever an arc is released. The electrical circuit breaker is an indispensable device that is greatly needed for every single step to ensure sufficient safety. CB can be used for low-voltage and high-voltage applications. However, we will clearly let you know about the low-voltage circuit breaker selection guide that may help you to select the right circuit breaker.

How to Select a Low Voltage Circuit Breaker?

Every single person is highly dedicated to safe their home appliances and any other electrical and electronic devices. To ensure proper safety from surge voltage or surge current the circuit breaker plays a leading role. But choosing a circuit breaker is one kind of challenge. Don’t worry we are going to share with you about low voltage circuit breaker selection guide. The circuit breaker is designed to provide better protection against over-voltage and overcurrent. You have to choose the right CB that is eligible to protect your crucial device. There are some key factors to choose the best circuit breaker, such as

  1. First of all, you have to decide what type of circuit breaker you need, such as do you need a standard breaker, do you need Ground Fault Circuit Interrupter (GFCI), or do you need Earth Fault Circuit Interrupter (EFCI). If you would like to use it in your kitchen, or bathroom then you can choose a GFCI circuit breaker.
  2. You should identify the renowned CB brands that have been performing better in the marketplace.
  3. In the third step, you should check the circuit breaker specification. In this case, you will be aware of your desired CB and what type of circuit breaker (CB) you are looking for.
  4. Whenever you are going to buy a CB then you must focus on some key features, such as operating voltage, load and tripping current, frequency, and the number of poles (single pole, double pole, etc).
  5. Check your desired CB physical specification, such as breaker connection (plug-in, bolt-on), breaker mounting type (DIN rail types, or panel mount type), and circuit breaker frame type.
  6. You must check the breaking capacity of the circuit breaker. Basically, the best circuit breaker has the highest breaking capacity within as short as possible time.
  7. You should remember that sometimes the circuit breaker goes bad. So check it before running the high-voltage machine.

How to Test a Low-Voltage Circuit Breaker?

Circuit breaker testing is the crucial part. It is because you need to be sure that your circuit breaker is working properly. Suppose you have a low-voltage circuit breaker but you never test it whenever you purchased it. You have installed it and somehow surge voltage or surge current appeared due to lightning or some other internal reason. In this case, your breaker did not trip due to anything failure of its mechanism or the breaker was not working properly to safe your device.

As a result, your device will be burned out successfully. For this reason, the best way is whenever you would like to install a CB in your homes, offices, and industries please test its working procedure. It means to test the circuit breaker before you install finally. We are going to share with you the low-voltage circuit breaker testing procedure.

  1. First of all, prepare your circuit breaker for testing purposes and connect your circuit breaker one phase with the testing probe and press your (CB) lever in on position.
  2. Suppose you have chosen a 90-ampere rating circuit breaker if the current becomes more than 90 Ampere then your breaker will automatically trip and stop the current flow and count the time to break (it is for single-phase load).
  3. If you have a circuit breaker for a three-phase load then you have to test the breaker for each phase, and you have to count the time by the same thing for another phase. If your circuit breaker trip for over current like the first phase then you can be sure that your breaker is able to trip whenever high current flow through it and it is ready to install.

 It is noted that if you have any 30 Ampere device you have to take a circuit breaker those have a breaking capacity at least three times higher than it. It means 30 * 3 = 90 Ampere. Because most of the load of the electrical power system is the inductive load. For this reason, whenever we start a single-phase load or three-phase load then the starting current becomes very high than the rated current. However, if the surge power or load current becomes more than 90 Ampere then your circuit breaker will trip.

It is noticeable that whenever we run motor single-phase or three-phase motor then we need an MCB circuit breaker. MCB means miniature circuit breaker, we can test the MCB circuit breaker by following the above testing process. However, we are showing here the MCB selection chart for motors then it will be clear for you. This MCB selection chart for 3 phase motor will show you what type of breaker you need to choose for your single-phase or three-phase motor.


On the other hand, a high voltage low current circuit breaker means that a miniature circuit breaker (MCB) is used for the low current rating. Basically, MCB is specially designed for due to this reason. This type of circuit breaker is used for those who have a 125 Ampere current rating. MCB offers better protection for short circuits and overload.

Can Low Voltage Trip a Circuit Breaker?

Can low voltage trip a circuit breaker? The answer is no. Low voltage has no effect on the CB though it becomes a single-pole circuit breaker or double-pole circuit breaker. Because circuit breakers don’t have access to a neutral wire. For this reason, Breaker cannot measure voltage so low voltage doesn’t matter. There are three main reasons for to occur low voltage, such as higher load, higher loss due to low efficiency, and bad wiring. However, circuit trips if overload and surge power occur and save the device from short circuit.

There are different types of circuit breakers in the power system and these are used for protection purposes. Basically, the lowest operating voltage circuit breaker is an air-break circuit breaker. Such type of circuit breaker is used in electricity generating station auxiliary protection and other industrial plant protection purposes.

What are low voltage circuit breaker ratings?

Low Voltage Circuit Breaker Ratings (LVCBR) is used to protect electrical equipment from damage caused by overcurrent conditions. LVCBRs can be rated at either 15A or 20A. When selecting an LVCBR, consider the following factors:

  1. Size of the load that the circuit breaker will handle.
  2. Type of wiring being protected.
  3. A number of circuits are protected.
  4. Location of the circuit breakers.
  5. Rating of other devices connected to the circuit.


Those who use electricity must need safe their crucial devices in their homes offices factories and other indoor and outdoor applications. In this case, two devices can be used electrical fuse and an electrical circuit breaker. Both of the works are in the same process (they resist the over-current). We have given here a low-voltage circuit breaker selection guide and referred to some other crucial things. We hope it may successfully help you to find a better low-voltage circuit breaker.

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