IEC Protection Classes
In today’s blog we will be discussing the basic IEC protection classes that are used to differentiate between the ground or earthing requirements of equipment devices, namely sockets and plugs.
Plugs and sockets used in electrical circuits are assigned a classification based on the insulation and grounding capabilities they have for the application in which they were designed. The IEC has established five protection classes for plugs and sockets used in electrical circuits. These classes are Class 0, Class 01, Class I, Class II, and Class III. Today, we will briefly discuss the Class 0, Class 01 and Class I.
Intended for use in dry areas, these appliances do not have a protective-earth connection and only have a single level of insulation. A single fault could cause shock. This risk of shock has led the UK to ban items in this class.
These appliances are similar to Class 0, but have an earth terminal – although it is unused given that two-core/two-conductor cable is used.
Appliances in this class are required to have their chassis connected to a ground. Because most Class I equipment is constructed with minimal insulation between the circuit and the chassis of the equipment, a third conductor, the ground wire, is required in order to protect the user of the equipment in the event of a short circuit. The ground wire provides a connection between the ground pin on the plug and the chassis of the equipment. The plug pin connects to the socket and removes any short-circuited current from the user, applying where it can be diffused safely. A grounded plug and socket pattern must have at least three pins or contact points.
Stay tuned for next’s week discussion of Class II (ungrounded) equipment.
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