Residual current circuit breaker models will include the number of poles, such as DZ47LE-16 2P C16A type residual current circuit breakers produced by TAIXI Electric, of which 2P is the number of poles. In addition, in the residual current circuit breaker will encounter such as 3P, 4P, 3P + N and other different types of poles, different poles and their own mean what it means. Here according to personal understanding, a brief introduction.
First, what is the number of poles. From a professional point of view, the so-called circuit breaker "pole" actually refers to the broken pole for the wire, but not necessarily provide protection for each knife. Popular point refers to the number of lines at the same time off, for example, 3P and 4P is that you can disconnect 3 or 4 at the same time. For example, the general distribution box installed more 3P, used in the control of three-phase AC circuit power supply three phase line. 4P can also be used in three-phase AC circuit control three-phase power supply, another control is often used as a switch normally open auxiliary contact, that is, when other controllers (such as PLC, etc.) need to collect the break The situation can be the junction as a sub-closing signal transmission into, which depends on the actual needs of the.
Next, we introduce the meaning of P and N in this series. According to the individual's understanding and some of the online data, from two aspects to discuss:
One: from the product classification
1P, 2P, 1P + N, 3P, 4P, 4P + N, P refers to the installation of the protection of the pole (knife pole), N refers to the neutral line only installed the knife, not installed protection module. 2P and 1P + N are bipolar switches, and 4P and 3P + N are called quadrupole switch, 1P + N, 3P + N because the neutral line is not installed protection, so cheap point, the neutral line with the phase line Knife pole with action. Some products also divided 1P + N into two: one with two module widths, one with only one module width (smaller).
1P: single-pole switch
2P: two-pole switch
3P: three-pole switch
4P: four-pole switch
1P+N: Single-pole switch with zero line terminal (zero line is not broken)
3P+N: Three-pole switch with zero line terminal (zero line is not broken)
Two: from the electrical technical aspects
Single-pole switch and two-pole switch, three-pole switch and four-level switch selection, in fact, look at the line of the neutral line need to be disconnected, you can determine the following points: 1. Consider the maintenance of security: TT system needs to be overhauled Neutral line, so the need for two-pole and four-pole switch, TN system, do a good job after the connection, in addition to special circumstances (see measures), do not need to disconnect the neutral line, the general election pole and three poles can be. Four-pole switch can be used as little as possible, because there is "zero" danger. 2. When there are two power supply, see if you need to isolate the two ground system. Another: 1P + N, 3P + N and 2P, 4P in the electrical are used as a poles, four pole switch to look at the need to determine the need to disconnect the neutral line, but the neutral current can not exceed the phase line, 1P + N, 3P + N can be selected from cost savings. If the neutral current is likely to exceed the influence of the phase line (harmonics and so on), 2P and 4P need to be selected.
1P (1 pole) switch: only one connector, can only disconnect a phase line, this switch is suitable for control of a phase "fire" line
2P (2 pole) switch: There are two terminals, one connected to a line of a zero line, this switch is suitable for controlling a phase of a zero
3P (3 pole) switch: There are three, three are connected to the "fire" line, this switch is suitable for control three-phase 380V voltage lines
4P (4 pole) switch: there are four, three are connected to the "fire" line, a zero line, this switch is suitable for control three-phase four-wire system
Finally, we say that we have found the same series of circuit breakers in the discussion of the above series, but some may have N, for example, 4P and 3P + N are four poles, then what is the difference between them, we How to choose?
According to the above discussion, both are four-pole switch, the difference is, 4P N line with protection, 3P + N of the N line is not protected, while 3P + N of the N-line without overload, short-circuit trip coil , Can not afford to protect the role of N-line and other 3-pole there is a mechanical relationship between.
These are personal experience and reference, the views of the Internet, summed up the problem of residual current circuit breaker series, but also hope to help you buy residual current circuit breaker.