Recently, people have been asking in the comments section how much amperage a circuit breaker is. Although the parameters of circuit breakers have been mentioned in other articles before, today I still feel like taking it out separately to explain.

When choosing a circuit breaker, one should start from three aspects - function, number of poles, and current. Through these three aspects, it is sufficient to choose the appropriate circuit breaker parameters for oneself.

What are the parameters of a circuit breaker

The parameters of the circuit breaker are generally written in the upper left corner of the product, as shown in the following figure as an example

When choosing a circuit breaker, we usually focus on the first two rows of parameters. The parameters of this circuit breaker are NBE7-63LE C63

Let's explain in detail what the combination of letters and numbers represents.

Function

Household circuit breakers generally only have two additional functions - leakage protection and overvoltage protection. The only thing that can be reflected in the parameters of the circuit breaker is leakage protection.

The letter "LE" in the parameter means "with leakage protection". For all other circuit breakers without leakage, simply remove "LE" from the parameters.

Taking the set of parameters mentioned above as an example, the parameter without leakage of the same model is NBE7-63 C63.

Therefore, whether or not to have leakage protection function can be seen from the parameters.

From the appearance, it goes without saying that a regular circuit breaker is not necessary. Circuit breakers with leakage protection and overvoltage/undervoltage protection are prone to confusion.

As the name of the leakage protection device accessory has already been written into the circuit breaker parameters, there are no markings expressing leakage protection on the leakage protection module.

However, the under voltage release accessory is not written into the circuit breaker parameters, so there will be a name annotation on the module. In the upper left corner of the module, MN is written, representing the undervoltage trip function. Written with MV, representing overvoltage trip function. Writing MN+MV represents having overvoltage and undervoltage trip function.

The functional options for household circuit breakers are limited, generally choosing the DZ47 model, and only installing leakage protection in the socket circuit is sufficient. Parameter example: DZ47-32LE C32

1、 Current

Current is a key factor in selecting a circuit breaker. Some circuit breaker models are not as easy to understand as the one above, such as DZ47-60 C32, and many people do not know exactly how many amperes it is.

Actually, what we usually refer to as' ampere 'refers to the rated current of the circuit breaker. What does rated current mean? It refers to the current in the circuit. Once it exceeds the rated current value, the circuit breaker will trip. This rated current is the number after C in the parameter.

For example, C32 means that if the circuit breaker exceeds 32A, it will trip; C20， It means that if it exceeds 20A, the circuit breaker will trip.

The number before C refers to the frame current of the circuit breaker.

The frame current refers to the maximum current that the circuit breaker can withstand, which means that if the current in the circuit exceeds this value, the circuit breaker may be burned out. For example, DZ47-60 C32 refers to the frame current of the circuit breaker being 60A - when the current in the circuit is 32A, the circuit breaker will trip. But if the current in the circuit exceeds 60A, there is a risk of the circuit breaker burning out.

Circuit breaker burnout may result in the inability to trip automatically. Therefore, using a circuit breaker with the same frame current and rated current carries risks.

When selecting the current of a circuit breaker, it is necessary to consider the actual situation, such as the rated power of the socket, the number of sockets, etc. Do not blindly pursue high current to avoid the situation where the circuit breaker does not trip after circuit overload.

2、 Extreme numbers

Pole number is another major indicator for circuit breaker selection, and 1 pole is also called 1P.

From left to right, there are 1P, 2P, 3P, and 4P circuit breakers respectively, with the latter two used for three-phase circuits

There are three types of circuit breakers used in household single-phase circuits: 1P, 1P+N, and 2P. Among them, a 1P circuit breaker refers to a device that can only disconnect the live wire and constantly monitor the current on the live wire. Once the current on the live wire reaches the rated current, the circuit breaker can provide protection for the live wire - tripping.

A 1P+N circuit breaker refers to a device that can disconnect live and neutral wires, but current detection can only detect live wires and provide protection for them.

2P circuit breaker can disconnect the live and neutral wires and simultaneously detect the current on both wires.

For general light circuits, 1P or 1P+N circuit breakers can be selected. The socket circuit must be equipped with leakage protection accessories. Generally, a 1P or 1P+N leakage circuit breaker is selected for a five hole socket; Three hole sockets must be equipped with 2P residual current circuit breakers.

From the above description, I believe everyone can easily understand how many amperes a circuit breaker is.