Class I Earthed Equipment
Class I equipment includes extension leads, multiboxes and other equipment that relies on an earth connection to ensure ongoing operator safety. It must always have an earth pin on the plug – it does not usually say that it is Class I, so the lack of the Class II symbol or the words ‘double insulated’ is the main determining factor.
The primary safety protection for the operation of Class I equipment is the earth conductor so this must be in good condition.
Usually, most Class I appliances (even outside of the AS/NZS 3551) have lots of exposed metal and are likely to be heavy to lift eg:
- Floor Polishers
- Radiant Heaters
- Microwaves
- Computers
- Some Vacuum Cleaners – NOT ALL
- Whiteware
- Electrical Machinery
- All Extension Leads and IEC Leads are also Class I
For medical equipment, in a patient/and or users environment, the most common class I item will be leads that are connected to other medical equipment or chargers.
NOTE
Any 3 pin make of plug you look at will have the bottom pin (earth pin) longer than the others so that this is the first pin to be connected and the last to be disconnected. This will help you to understand the importance of the earth conductor.
It is important to note that sometimes it is not easy to establish whether something is Class I or Class II. If unsure, the first thing to do is treat it as if it is a Class I appliance and test it accordingly. If the equipment passes the test then it is Class I. If it fails it could be because either it is faulty or else it is Class II. In this instance refer to manufacturer/supplier for advice or to a qualified repair company.
If at any point during the Inspection or Testing process it becomes UNCLEAR whether an item should be considered safe or not, then it should be considered UNSAFE.