Class II equipment

From Electrical Installation Guide

Class II equipment symbol: DB431010.png

These appliances are also referred to as having “double insulation” since in class II appliances a supplementary insulation is added to the basic insulation (see Figure F74).

No conductive parts of a class II appliance must be connected to a protective conductor:

  • Most portable or semi-fixed equipment, certain lamps, and some types of transformer are designed to have double insulation. It is important to take particular care in the exploitation of class II equipment and to verify regularly and often that the class II standard is maintained (no broken outer envelope, etc.). Electronic devices, radio and television sets have safety levels equivalent to class II, but are not formally class II appliances
  • Supplementary insulation in an electrical installation: IEC 60364-4-41(Sub-clause 413-2) and some national standards such as NF C 15-100 (France) describe in more detail the necessary measures to achieve the supplementary insulation during installation work.
Fig. F74 – Principale of class II insultation level (IEC 60364-4-41 sub-clause 412)

A simple example is that of drawing a cable into a PVC conduit. Methods are also described for distribution switchboards.

  • For ASSEMBLIES, IEC 61439-1 describes a set of requirements, for what is referred to as “total insulation”, equivalent to class II equipment
  • Some cables are recognised as being equivalent to class II by many national standards.