There are two main factors that determine the safety characteristics of the isolation transformer.

1. The secondary line of the isolation transformer is not connected to the earth.

First of all, it is generally understood that the power supply system in China generally uses a three-phase four-wire system when providing low voltage to the user. The neutral line is grounded, commonly known as the point. That is, the line to the user's home, one of which is the fire line and the other is the zero line. It is in the same position as the earth, and when the person standing on the ground comes into contact with the fire line or the conductor connected to the fire line, the current enters the human body to the earth from the fire line, forming a loop through the ground line, causing electric shock. The secondary line of the isolation transformer is not connected to the earth, and there is no potential difference between any two lines and the earth. Therefore, under normal circumstances, when the user touches any line, no electric shock will occur.

2. The input and output of the isolation transformer are completely isolated and have an insulator in the middle.

The input and output of the isolation transformer are independent and there is no common line. At the same time, when manufacturing the isolation transformer, the manufacturer will apply insulating varnish on the outside of the winding. The used wire is also known as the "enamel wire", and the enameled wire can effectively realize the electrical isolation between the input and output terminals, thus being safe and effective. The risk of electric shock to the user due to accidental contact with the charged body is avoided.

But in fact, this "security" is not absolute, there are two points that require special attention from the user.

1. The user cannot touch the secondary ends of the isolation transformer at the same time, otherwise there is a danger of electric shock.

2. The secondary ends of the isolation transformer cannot be grounded, otherwise there is a danger of electric shock.