Please teach me what is the principle behind this

吾妻思萌

Please teach me what is the principle behind this [Copy link]

What is the principle of grounding? Why is there an abnormal grounding? It is on the water heater at home.

maychang

[Why is there an abnormal grounding? It's on the water heater at home]

The water heater manufacturer has built the leakage protector into the plug.

fjdeepblue

This is a leakage protection switch. Its principle is to detect zero-sequence current. If there is no leakage, the currents of the neutral wire and the live wire are equal. If there is leakage, they are not equal.

吾妻思萌

[Why is there an abnormal grounding? It is on the water heater at home.] The water heater manufacturer built the leakage protector into the plug.

Teacher, is this not an air switch?

tagetage

This is a simplified version of the switch and socket ground leakage detector.

maychang

Azuma Simeng posted on 2024-2-15 09:24 Teacher, does this inherit the air switch?

There are two types of air switches: one without leakage protection and one with leakage protection. The air switch with leakage protection is actually the leakage protector next to the air switch pushing a small lever to activate the leakage switch. As for whether the leakage protection in the picture has an air switch, I didn't take it apart to see, so I don't know.

黑屋白巫

I think it should be the literal meaning: there is a problem with the ground wire of the socket. Maybe the socket is not connected to the ground wire, or the ground wire is broken. Or check whether the circuit breaker of the corresponding line is normal.

chunyang

According to safety regulations, the water heater rack must be reliably connected to the ground. If not, it is considered "abnormal grounding", which can be achieved by detecting the induced voltage of the rack. The floating rack will sense the voltage through the distributed capacitance, and the voltage can be detected as long as the input impedance of the detection circuit is high enough. If the rack is reliably connected to the ground, the induced voltage will be very low, and it can be considered "normal grounding" if it is lower than the detection threshold.