Class of Insulation

Class Symbol Description
Class 0   Functional insulation without earthing devices.
Class I   Functional insulation with terminal or cable complete with conductor for earthing.
Class II Double insulation or reinforced insulation without earthing devices.
Class III For connection at very low voltage. With no other internal or external circuits operating at voltages different from the very low safety voltage.

Degree of IP Protection

Class Symbol Description  
IP20   Solid bodies larger than 12mm diam
IP23 Solid bodies larger than 12mm diam. Rainfall
IP40   Solid bodies diam 1mm
IP43 Solid bodies diam 1mm. Rainfall
IP44 Solid bodies diam 1mm. Sprays from all directions
IP54 Partial protection against dust. Sprays from all directions
IP55 Partial protection against dust. Jets from all directions
IP65 Sealed against dust and jets from all directions
IP68 Sealed against dust operation while submerged for long periods at depth.