In our life, we often see electric sparks, especially when the plug or socket on the socket. Ordinary people's popular "electric spark" actually has a professional term called "arc".

Generation of Arc:

The arc is because when two conductors (one of which has a voltage of more than 20V) are closed but there is no direct contact (virtual connection state), the voltage directly passes through the air to generate current. Due to the high air resistance, the current in the air has the characteristics of high temperature and Luminescence - when the current flows through almost all high resistance conductors, it will emit high temperature and light, such as tungsten filament (incandescent lamp), electric furnace, etc.

Let's say in more detail: when two conductors are wrongly connected, the electric field intensity is greatly affected by the curvature of the contact surface. Under the action of strong electric field, the surrounding air is ionized and produces a large number of charged ions.

These ions move under the action of an electric field and produce an electric current. But the electric field here is not closed, but in the air. When neutral particles in the air (dust, non ionized air, etc.) come into contact with charged ions, they will release kinetic energy, resulting in luminescence and heating.

Arc hazard:

Arc has two main hazards:

1. The temperature of the arc itself is very high, which is a test of the flame retardancy of plugs and sockets. If the arc is large, it may pop up and hurt people, or ignite other objects.

2. Arc has certain corrosivity to metal. Sockets that ignite frequently may affect the flatness of the internal spring clip - a damaged spring clip will not only affect the conductivity, but also lead to the next stronger ignition.

Arc protection

In order to prevent the generation of electric arc, people think of many methods. We have three things in common in our lives:

1. Increase the strength of the spring clip and the thickness of the plug, tighten the plug directly, shorten the virtual connection time and avoid air ionization.

2. The circuit breaker is equipped with arc extinguishing grid. After the arc is generated, the arc will be elongated, cooled and extinguished with air in time (all household circuit breakers are also known as "air switches").

3. Improve the popularization rate of safe electricity use knowledge, and try to cut off the power supply when pulling and inserting the plug of high-power electrical appliances (directly cut off the line, or pull and insert after turning off the electrical power supply).