GB/T 32704-2016Safety requirements for laboratory instrument and equipment - Balance instrument (English PDF)

3.1 anti-shock protection equipment

3.1.1 Class I equipment class Iequipment

Use the following methods to obtain protection against electric shock equipment.

--- the use of basic insulation;

--- also equipped with a connection device, so that those in the basic insulation once the failure will bring dangerous voltage conductive parts and buildings

The protective earth conductor in the wiring is connected.

Note. Class I equipment can have double insulation and reinforced insulation parts.

3.1.2 Class II equipment class IIequipment

Anti-shock protection not only rely on basic insulation, but also take additional safety protection equipment (such as the use of double insulation or reinforcement must

Edge of the equipment), such equipment does not rely on the protection of grounding, do not rely on the installation of protective measures.

3.1.3 Class III equipment class IIIequipment

The anti-shock protection is a device that is powered by a safety extra-low voltage (SELV) circuit and does not generate dangerous voltages.

Note 1. The voltage limit under normal operating conditions is less than the specified value in 6.3.1a of GB 4793.1-2007 is considered to be a safety extra-low voltage.

Note 2. For Class III equipment, although no anti-shock requirements, but the other requirements of this standard are applicable.

3.2 Protection isolation

Use basic protection and additional protection between circuits (basic insulation plus additional insulation or protective shield) or use such as reinforced insulation

The protection of the protective measures.