How to Identify Class I and Class II Electrical Equipment

One of the first things you need to work out before testing an appliance is whether it’s Class I or Class II.

Why? Because it affects the tests you need to perform.

There are a few clues that can help you identify the class, but you don’t want to make assumptions based on whether something is metal, plastic or how many pins are on the plug.

Check the Manufacturer Label First

In this quick video, Mark, one of our Test & Tag trainers, shows where to find the manufacturer's label or rating plate and what to look for when identifying Class I and Class II equipment.

For Class II equipment, one of the key things to look for is the square-within-a-square symbol. This indicates the equipment is double insulated and does not rely on protective earthing.

What is Class I Equipment?

Class I equipment relies on protective earthing as part of its protection against electric shock.

It generally has an earth connection, and may also have a metal enclosure or a three-core cable, but these features shouldn't be used on their own to classify the appliance. 

Common examples can include desktop computers, kettles, microwaves and fridges. 

Always check the manufacturer's label, markings and equipment information rather than relying on appearence alone. 

What is Class II Equipment?

Class II appliances use double or reinforced insulation and do not rely on protective earthing. It is normally identified by the square-within-a-square symbol.

Common examples can include hair dryers, chargers, some power drills and household appliances.

And remember, a plastic enclosure doesn't automatically mean something is Class II.

Class I vs Class II at a Glance