Electric shock protection standard
The EN standard, which is a unified European standard, is an international standard for electric shock. In that EN, “EN61140” divides the protection method against electric shock into three classes: class I, class II, and class III.
In reality, the type of transformer installed determines the protection class for electric shock.
Class I equipment
Protects electric shock protection only with basic insulation. If the basic insulation is damaged, the conductive part where a dangerous voltage may be applied is grounded. Switching power supplies belong to this class I equipment, and the transformer has a ground terminal that can be protected and grounded.
Class II equipment
Safety measures of “Double insulation” that protects against electric shock with basic insulation and “Supplementary insulation (thickness of insulation is secured 0.4 mm)” or “Reinforced Insulation” that has more protection performance than this Double insulation It is a device that has been given.
Class II transformers require all windings to be covered with insulation.
Class III equipment
A device that protects against electric shock with a SELV (Safty Extra-Low Voltate) circuit and does not have a dangerous voltage inside the device. There is no dangerous voltage above DC60V in the equipment.
