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Foshan Shunde Guanyuda Power Supply Co., Ltd
Switching Power Supply

Switching Power Supply: Class I, Class II and Class III

CLASSI, II, III ” are mainly concerned with the insulation system of switching power supply, coming from the IEC standard:

CLASS I: the electric shock protection of the product depends not only on the basic insulation, but also on the grounding mode; ( 3 pins plug)
CLASS II: the product’s protection against electric shock depends not only on basic insulation but also on additional safety measures, such as double insulation or enhanced insulation, but without grounding or depending on installation conditions; (2 pins plug)
CLASS III: the product’s anti-shock protection depends on the power supply voltage as safe and ultra-low voltage (SELV), and does not generate dangerous voltages:

The difference between Class I and Class II of power supply are shown as below:
1. Appearance
Class I: 3 pins plug;
Class II: 2 pins plug;

2. Leaking Current
Class I: 0.75mA;
Class II: 0.25mA;

3. Hi-Pot
Class I: 1500VAC, 60SEC, 10mA;
Class II: 3000VAC, 60SEC, 10mA;

4. Rating Label
Class I: without the mark of “回”;
Class II: with the mark of “回”;

5. Protection grounding resistance test
Class I: yes;
Class II: no;

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