Sunpower UK's Electronics Glossary - IEC Protection Classes
IEC Protection Classes: Used in the electrical appliance manufacturing industry to differentiate between the protective earth connection requirements of devices.
These appliances must have their chassis connected to electrical earth (ground) by an earth conductor. A fault in the appliance which causes a live conductor to contact the casing will cause a current flow in the earth conductor. The current should trip either an over current device or a residual current circuit breaker, which will cut off the supply of electricity to the appliance.
A Class 2 or double insulated electrical appliance is designed in such a way that it does not require (and must not have) a safety connection to electrical earth (ground).
Designed to be supplied from a SELV power source. The voltage from a SELV supply is low enough that under normal conditions a person can safely come into contact with it without risk of electric shock. The extra safety features built into Class 1 and Class 2 appliances are therefore not required.
This Electronics Dictionary is a free service provided by Sunpower UK, and includes an ongoing list of current electronics vocabulary in use today. Sunpower UK sells a bespoke product range of electronics power supplies suitable for all your power supply needs, be it large or small.