What does P mean in circuit breaker? How to choose?

Circuit breaker, to put it simply, is a kind of electrical appliance that can disconnect the circuit power supply, from the previous gate knife type to the ceramic fuse switch, and then to the current air switch and leakage protection air switch, which is gradually improved and improved in safety.

The P mentioned above is mainly for air switches or leakage protection air switches, to put it simply, P here refers to the number of decoupling electrodes of the air switch, that is, there are several pushers we see, such as 1 pusher, almost this switch is a single P switch, it has no connection with the P of the air conditioner, and the p of the air conditioner refers to the power.

How many P's are there in an air switch in life?

Single P-type switch: such is common, it has only one terminal port, single in and single out, usually connected to the live wire of the home, when there is an overload in the line, the air switch will heat up, the internal magnetic decoupling will fall off, disconnect the load of the live wire, usually the developer configuration is also like this.

2P type switch: such a switch can also be common in the meter box, it has two terminals, respectively connected to the red line, zero line, double in and double out, when the load occurs in the case of overcurrent, its internal magnetic decoupling will fall off at the same time, only to hear a crisp "snap" sound, instantly disconnect the load of the live wire zero line, in our home distribution box is also a lot.

3P type switch: This kind of switch is less common, because it will not be used in some 220V circuits or environments where the house is not too large, it is a switch specially used for three-phase electricity (also called power electricity, 380V).

This kind of switch has three wiring electrodes, three in and three out, respectively, are connected to the live wire, mainly used in the main switch at home or the equipment that needs three-phase electric power supply to directly use such a switch, where to connect the zero wire and grounding wire in the three-phase electricity? They have their own arrangements, and they won't be randomized, so I won't express them here.

4P type switch: such a switch is also rare, it is an additional wiring electrode on the 3P type switch, in addition to the electrodes of 3 live wires, there is also an additional neutral wire wiring pile, it is a four-in and four-out switch. This kind of switch is also used in some large villas.

The above is the current air switch of several types, usually in addition to the difference in the rated current of the switch itself, it is the difference in its wiring electrode. In addition to the matching degree of the rated current, there are the following precautions for the use of switches in the home:

1. Is there a demand for leakage protection?

The condition for the air switch to trigger the protection mechanism is that the load is overcurrent and short circuit, and the magnetic hook inside the switch will instantly decouple, disconnect the live wire or disconnect the neutral line of the live wire at the same time.

However, when leakage occurs in the load, the air switch will no longer produce protection, so it is necessary to consider the air switch with leakage protection for some circuit loads, which is usually expressed in the way of P+N, such as 2P+N, N represents.

In the air switch with N representation, the neutral line should be connected to the N terminal, such as 1P+N, which makes the single in and single out mentioned above become a double in and double out mode, so that the air switch has overload, short circuit and overcurrent protection, and also has leakage protection.

Obviously, the air switch with leakage protection is more meaningful, and it is usually used in the circuit of some high-power electrical appliances, such as air conditioners, ovens, steamers, etc.

2. Is there enough space in the distribution box? Are you well funded?

Since I mentioned earlier that the P+N switch is very comprehensive in the protection of users in life, do we replace everything at home with this?

In fact, there is no need to do so at all. Because the P+N switch occupies a wider space than the ordinary air switch, if it is replaced with an air switch with leakage protection, it will bring insufficient space to the distribution box, and the expansion of the distribution box is very troublesome, and the general decoration party is unwilling to expand the distribution box.

Another reason is that their price difference is also very large, the number of air switches in a family is usually more than 10, so there is also an expense.

In daily work, the main switch is usually used in the way of P+N, so that the main switch has the function of leakage protection, when the back of the load circuit, as long as there is leakage, the main switch will also be disconnected from the zero live line for time, to achieve the purpose of protection.

However, in such a situation, the specific circuit of the back-end load leakage is not obvious, and it takes a lot of troubleshooting time, so you can use P+N in the circuit where the high-power electrical appliances are located in life.

summary

The P in the circuit breaker is used as a way to identify the wiring port, and it is also a way to judge the power supply mode, for example, if you see a 3P or 4P circuit breaker, you will conclude that the house uses a 380V power supply. In addition, the P+N in the circuit breaker is an air switch circuit breaker with leakage protection, and its protection function is compatible with leakage protection.

What does P mean in circuit breaker? How to choose?

What does P mean in circuit breaker? How to choose?

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