What's the difference between Class I lights and Class II lights? Who can tell me?

According to the safety performance of lamps and lanterns, lamps and lanterns are divided into four categories, namely:

Class 0 lamps: rely on basic insulation as electric shock protection-only rely on pvc insulation of wires. Once the basic insulation fails (broken wires, such as broken skin when crossing lines), it will lead to electric shock accidents and fire hazards. Electric shock protection must depend on the environment.

A class of lamps: the protection against electric shock depends not only on the basic insulation, but also on additional safety measures, that is, connecting the accessible conductive part to the protective grounding conductor in the fixed line, so that the accessible conductive part will not be charged when the basic insulation fails. (Class 0 lamp+ground wire)

Class II lamps Class II lamps

(1) Definition of Class 2 lamp:

The protection against electric shock depends not only on basic insulation, but also on additional safety measures, such as double insulation or reinforced insulation, but not on grounding or installation conditions.

(2) Characteristics and standard requirements of Class 2 lamps:

1. This lamp can have one of the following forms:

A) The lamp has a complete shell, which is made of durable solid insulating material and covers all metal parts. Except that nameplates, screws, rivets and other small parts are completely isolated from live parts by insulating materials, such insulation is at least equivalent to strengthening insulation. This kind of lamp is called insulated shell type I lamp.

B) The lamps and lanterns of solid Full Metal Jacket are internally insulated by double insulation, except for the parts that obviously cannot be insulated by double insulation, which are reinforced by insulation. This kind of lamp is called Class II lamp with metal shell.

C) a lamp of the above-mentioned combination type of a) and b).

2 insulation shell The shell of N-type lamp can be part or all of supplementary insulation or enhanced insulation.

If grounding helps to start, but it is not directly connected to accessible metal parts, the lamp is still regarded as a Class II lamp. The lamp cap shell of the light source and the starting belt of the light source are not considered as easy-to-touch metal parts, except for the live parts determined by the tests in Appendix A. ..

If the lamps with double insulation and/or reinforced insulation have unified grounding terminals or contacts, the lamps are of Class I structure. However, if the fixed Class II lamp is used for loop installation, it can have an internal terminal to maintain the electrical continuity of the grounding conductor, which does not terminate in the lamp. The internal terminal is isolated from the contactable metal by secondary insulation.

Class III lamps: The power supply used is safe and ultra-low voltage, and the low voltage higher than SELV(36v) will not be generated inside the lamps: the commercial power is converted into a low voltage of 36v (by adding a transformer).

It can be seen that Class 0 lamps are lamps without special grounding devices. This kind of lamp has the lowest safety performance.