How to choose a household miniature circuit breakers (mcb)?

(1) When choosing a household miniature circuit breaker, first determine the current of the load, and then determine the rated current of the micro-break

First of all, calculate the current of all loads in the line according to the power, and then multiply it by the synchronization coefficient to obtain the calculated current.

The rated current of the micro-break must be greater than the calculated current.

(2) Determine the rated ultimate short-circuit breaking capacity Icu

When selecting, make sure that the short-circuit breaking capacity is greater than the expected short-circuit current value on the line. If it is not calculated, the ultimate short-circuit breaking capacity of 10kA is preferred.

(3) Choose a reliable brand

There are many brands of miniature circuit breakers types, and the price varies greatly. In order to ensure the safety of your electricity use, please be sure to choose a reliable brand. CSQ has 30+ manufacturing experience and exports to more than 50 countries around the world. Certificates are complete, with an independent laboratory, which can provide complete experimental reports. Safe and trustworthy.

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（4）Determine the number of poles of the micro-break, including 1P, 2P and 1P+N

The number of poles of the micro-break is closely related to the installation position of the micro-break and the grounding system.

This is the TN-C-S home power distribution system, and it is also an optional solution for most of our home power distribution systems.

In the figure, the neutral line is repeatedly grounded outdoors and separated into the neutral line N and the ground line PE to enter the household. The main switch of the indoor distribution box adopts 2P micro-breaker, which can simultaneously connect and disconnect the phase line and the neutral line. There are 4 outputs in the picture, all of which use 1P micro-break. In addition, refrigerators, kitchen appliances and sockets are equipped with leakage protectors, and lighting and air conditioners generally do not need to be equipped with leakage protectors.

If the grounding system is TN-C directly into the home, no matter it is the incoming line micro-break or the feeder micro-break, only the 1P specification can be used.

Sometimes we can replace the 2P micro-break with a 1P+N micro-break. The 1P+N micro-break has two poles. The pole connected to the phase line L can implement overload and short circuit protection, while the pole connected to the neutral line N has no protection, and is essentially an isolation switch. In the 1P+N switch, the pole marked with P must be connected to the phase line, and the pole marked with N must be connected to the neutral line, and the two must not be interchanged.