Electricians generally recommend homeowners to install circuit breakers for the safety of residential electricity use. This is because when a fault occurs in the home's wiring, the circuit breaker can automatically trip and cut off the power, thereby reducing the loss of the accident. But do you know how to wire a circuit breaker? Is it also "neutral on the left and live on the right"? Qingdao Cable will tell you.
What is a circuit breaker?
A circuit breaker is a switch device capable of making, carrying, and breaking the current under normal circuit conditions, as well as making, carrying, and breaking the current under abnormal circuit conditions (including short-circuit conditions) within a specified time. It is a type of switch, yet different from the ones we commonly use. Circuit breakers are primarily designed to interrupt the current in high-voltage circuits, allowing for a rapid shutdown of the current when our system experiences a fault. This prevents the situation from escalating further, serving the purpose of protecting people's property. It is an excellent safety protection device.
Our lives are now better protected with the addition of circuit breakers, which have gradually become a part of people's daily lives, bringing us a safer environment.
Left Zero, Right Fire
I remember first hearing "left zero, right fire" in my middle school physics class, when I was rather clueless. It wasn't until my college courses that I truly grasped the meaning of the term.
The so-called "left zero, right hot" simply refers to the order of the socket prongs—facing the socket, the left prong is the neutral wire, and the right prong is the live wire, that's all.
Plugs may not necessarily be "left neutral, right hot" when wiring. Some terminal screws are arranged horizontally, but when you face the terminal screws (the back of the plug), the order of the terminals is the reverse of the order of the holes, becoming "left hot, right neutral." Some terminal screws are arranged vertically, making the concept of left and right even more irrelevant.
During actual wiring, the wire lug markings should be the guiding factor. Those marked with 'L' are for the live wire, while those marked with 'N' are for the neutral wire.
Section 3: Wiring Position of Neutral to Neutral
Any residual current circuit breaker cannot function without a neutral wire; the absence of a neutral wire is due to a wrong connection. In residential residual current circuit breakers, if categorized by poles, they can be divided into two types: 1P and 2P.
Both switches have two sets of terminals (one input and one output count as a set). Among the two sets of 1P leakage terminals, one set is marked with "N." During wiring, the neutral wire should be connected to this set of terminals, while the remaining set is connected to the live wire—do not remember "left neutral, right live" like with plug wiring. The direction of the neutral and live wires on the switch is not fixed; the terminal order varies by brand and model of the product. When wiring, use the actual position of the "N" terminal as the standard.
The two sets of terminal blocks with 2P leakage have no markings, meaning we can choose the wiring sequence at will. However, it is generally recommended to follow the 1P leakage wiring sequence inside the distribution box to ensure both sequences are identical. This way, the wiring will look neater and future maintenance will be more convenient.
In any case, the neutral wire will not be left unconnected to the switch.
How should circuit breakers be wired?
Flip the circuit breaker towards you, taking a 2P breaker as an example, as shown in the following image. The two upper terminals typically represent the input side, while the two lower terminals denote the output side. Since this is a 2P breaker, it can control the on/off of two circuits. The terminal labeled with an uppercase "N" on one side indicates the neutral wire is connected, and the other is for the hot wire.
In fact, as mentioned above, circuit breakers generally have high power ratings (compared to the power used for residential electricity), so for safety, additional 1P circuit breakers are often added at the back of the circuit. These 1P circuit breakers typically have lower power ratings. For a 1P circuit breaker, it's sufficient to connect a hot wire from a 2P circuit breaker directly. Of course, for a 2P circuit breaker, you can also connect one hot wire and one neutral wire. If the circuit breaker does not have an N symbol, it's usually connected left for hot and right for neutral, which is the opposite of the standard connection on a plug, where the standard is left for neutral and right for hot.
What if it's reversed?
Reversing the neutral and live wires doesn't pose a significant hindrance for 2P circuit breakers and 2P residual current circuit breakers; the only impact is that it appears irregular. During maintenance, it requires a recheck of the neutral and live wires, causing a slight inconvenience.
During the disconnection of a 1P+N circuit breaker or a 1P residual current circuit breaker, only the live wire—the wire connected to the unmarked terminal—is disconnected. If the neutral and live wires are mistakenly connected, the neutral wire is actually disconnected when the circuit breaker trips. Although there is no current in the circuit at this point, voltage remains. Touching it can still cause electric shock.
The neutral wire of the 1P circuit breaker is on the neutral busbar, making it highly unlikely to be connected incorrectly. The consequences of connecting the 1P circuit breaker incorrectly are the same as those of reversing the neutral and live wires in a 1P+N circuit breaker.
