What is a Double Insulated Electrical Appliance?

A Class II or double insulated electrical appliance is one which has been built in such a way that it does not require a connection to electrical earth (ground).

Double Insulated/Double Insulation

The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing. This is usually achieved at least in part by having two layers of insulating material surrounding live parts or by using reinforced insulation.

In the United Kingdom, a double insulated appliance must be labelled Class IIdouble insulated, or bear the double insulation symbol (a square inside another square).

An example of a double insulated electrical appliance could be an electric drill or a desk fan. Other items that are class 2 could be a lamp or a hand blender.

The bit not many people realise is that double insulated appliances don’t actually require the portable appliance test per say, but they do need a regular visual inspection by a competent person. The competent person is someone who knows about the appliance such as the maintenance engineer or IT consultant; but the best person is the PAT Testing engineer.

Double insulated equipment would usually be inspected as part of your ongoing PAT Testing regime but it shouldn’t need to be inspected as class I appliances that undergo regular portable appliance tests.

By |2020-01-20T21:14:08+00:00June 12th, 2013|PAT Testing Info|Comments Off on What is a Double Insulated Electrical Appliance?

About the Author:

I am Richard Ayre; editor for this site, owner of the site and the business, and a PAT testing engineer with over 10 years experience. I consider myself an expert in testing IT equipment in office environments; I have worked in many different industries for hundreds of different clients testing all kinds of electrical equipment. I am also Operations Director for the Portable Appliance Testing Trade Association As well as being the business owner I am also an employer; based in Wallsend near Newcastle upon Tyne. I am also involved in the running of the Portable Appliance Testing Trade Association as Operations Director and joint founder. "PATTA" attends important meetings and provides representation for the smaller businesses that do PAT testing in the UK, when decisions are being made that affect them.