What Is Class III Electrical Equipment?

Class III equipment is designed to operate at safety extra-low voltage (SELV). Protection against electric shock relies on the equipment being supplied at this low voltage, and voltages higher than SELV are not generated within the equipment.

Unlike Class I equipment, Class III equipment does not rely on protective earthing.

When Is the Class III Symbol Used?

The Roman numeral III inside a diamond identifies equipment classified as Class III. It should only be used when the electrical design of the product meets the applicable requirements for Class III construction.

Simply operating at a relatively low voltage does not automatically make a product Class III.

Class I, Class II and Class III

Class I equipment uses protective earthing as part of its protection against electric shock. Class II equipment relies on double or reinforced insulation, while Class III equipment relies on operation at safety extra-low voltage.

These classifications describe different methods of protection and should not be used interchangeably.

You Might Also Need These Symbols

Depending on your product, see also the Protective Earth and Class II Double Insulated symbols. Electrical products may also require the CE or UKCA mark and, in the EU, the WEEE crossed-out wheeled bin.

Download

Download the Class III symbol below in SVG, PNG and PDF format.

class-III-appliance-symbol.pngclass-III-appliance-symbol.svgclass-III-appliance-symbol.pdf

Use this symbol only for equipment that meets the applicable requirements for Class III construction. Do not use it simply because a product operates at low voltage.

Looking for another electrical marking? View all electronics symbols.