GB/T 22764.4-2008Cabinets for low-voltage switchgear - Part 4: Electrical safety requirements (English PDF)

3.1 Overview

Electrical safety designed primarily to prevent the risk of two types.

---electric shock;

--- Burns due to high temperature may be caused by fire and other harmful effects.

Therefore, the basic principles of security is protection against electric shock and thermal effects protection, electric shock protection can be applied to the product, but also can be used in production

Product or part of a device.

Electrical safety design generally consists of low-voltage and low-voltage cabinet manufacturer of complete sets of equipment manufacturers together.

3.2 direct contact with the protection of design requirements

Direct contact protection design should meet the dangers and livestock that may occur in contact with live parts of electrical installations should be protected. This

One kind of protection obtained by the following method.

--- Prevent current from any human or animal body by;

--- Can limit the current through the body, so that it is lower than current shock.

3.3 indirect contact protection design requirements

Indirect contact hazard protection should be designed to meet the humans and livestock in case of failure of the contact with the exposed conductive parts that may arise should the anti

Protection. One of the following methods can be used to obtain this protection.

--- Prevent fault currents from any person or animal body by;

--- Limit fault current through the body to a value lower than the shock current;

--- In case of failure, when a person or animal by touching the exposed conductive parts which may result in a value equal to or greater than the current shock

The current through the body within a specified time automatically cut off power supply.

3.4 Protection against thermal effects of the design requirements

Protection against thermal effects should be designed to meet the product is not dangerous due to high temperature or electric arc and ignite flammable occurred and normal operation of the product […]