Now more and more people want to install smart homes in their new homes when they are renovating, and enjoy the smart life brought by technology. When we search for smart switches, we will find that there are two types of single fire wire switches and neutral wire switches. They look exactly the same. What is the difference between single line smart switch , or with neutral line smart switch?

Today we will talk about the difference, and what kind of scene it is suitable for smart home use.

       We have to start with the circuit at home. The traditional circuit uses a mechanical switch to physically disconnect the neutral wire loop to control the light on and off. Of course, if you have multiple lights on a circuit, this switch will control the light on and off at the same time. I have learned physics in this junior high school. I hope you haven't returned it to the teacher.

       If we want to remotely control this switch or link with other equipment to realize intelligence, the easiest way is to add one to the mechanical switch that can receive instructions and control the mechanical switch, so you can send remotely Commands or other devices can send commands to control this switch, isn't it simple?

       In fact, it is not as simple as we thought. When you remotely control the switch to turn off, the switch itself has no electricity, because the entire loop is disconnected, and you can no longer close the switch remotely. It's kind of like you lock yourself out without taking it out. So this method fails.

　　 Is there any way to make this switch be able to supply power independently, so that the opening and closing of the circuit will not affect the work of the switch itself, such as using a battery to power the switch alone?

       If you use a battery to power the switch, the biggest problem is that the replacement of the battery requires the disassembly of the switch panel, which may be exposed to strong electricity, so it is best to be operated by an electrician with professional knowledge. After all, life safety is involved, so this solution is relatively Difficult to operate, you can't change the battery once, please call an electrician for a while.

　　 Another way is whether we can add a neutral line to the switch, so that the switch has an independent loop, so that the switch can be powered independently, and the line switch of the light bulb does not affect the work of the switch. As shown below:

Our traditional switch is called single fire, this kind of switch that adds a neutral wire to the switch is called neutral fire switch. Last comparison chart.

　　Single fire switch: except for the line connecting the switch to the light, there is only one live wire access switch (traditional switch)

　　Zero-fire switch: In addition to the line connecting the switch to the light, there is a live wire and a neutral wire switch

　　 The zero-fire switch must be installed after the renovation of the home’s electrical circuit is completed during the renovation. After the renovation of the water and electricity, the zero line cannot be added.

If it is an old house or a house that has been renovated, the switch cannot add another zero line, can it not be used as a smart home?

       It's not. As mentioned above, the problem with the single line switch is that when the circuit is disconnected, the switch itself is also powered off, so if we can not only physically disconnect the wires but also control the light switch, this problem can be solved. Engineers modified the switch: the switch is not a mechanical switch to physically disconnect the circuit, but a load is added to the circuit between the switch and the light bulb. When the switch is closed, only a small current flows through the switch and the light bulb due to the load. The current passed is too small to light the bulb while maintaining the switch operation, thus solving the problem of single line switch.

       The load must ensure that the current passing through is small enough to not light the bulb while maintaining the switch. Therefore, the single-fire switch has certain requirements on the power of the lamp. If the power of the lamp is too small, it is easy to be lit by the small current passed or flicker . Therefore, the single fire wire switch has certain requirements on the power of the lamp, for example:

       A small number of lamps are connected to a single fire wire switch. Why does the lamp flash when the lamp is turned off?

       Answer: When a single line switch takes power, a small current needs to pass through the switch and also through the lamp, so there are certain compatibility requirements for the lamp. Lights with a power lower than 5W may flicker or dimly bright; light strips driven by high-voltage direct power supply will flicker after turning off the lights. If there is a step-down driver, the flickering can be avoided.

       I have talked about the origin and characteristics of smart single line switch and with neutral line switch above. I hope you can choose the smart switch socket product suitable for your family.

       TRANSMEI SMART HOME provide the smart single fire wire switches, and with neutral wire smart switches,both in WIFI and ZIGBEE 3.0. as well as various smart socket products.

 Welcome to contact us from website:  www.transmei.net.