Anderson plugs - Classification of plugs

According to function, it can be divided into:

Earphone plug, DC plug, audio plug, USB plug, video plug, microphone plug, charger plug, mobile phone plug, etc. Internationally, household appliances are divided into three categories:

A type of electrical appliance refers to an appliance with only one layer of insulation, which must be equipped with a leakage protector and grounding protection (i.e. requires a three pin plug). Such as air conditioning, machine tools, motors, etc.

Class II electrical appliances have double-layer insulation measures and need to be equipped with leakage protectors, which do not require grounding protection (i.e. can use a two pin plug). For example: TV, electric fan, desk lamp, etc.

Three types of electrical appliances are those that use safe voltage, generally ranging from 12-36V

So the top pin of the three pin plug is used for grounding protection.