There are 3 main types of appliance commonly encountered in normal business and domestic environments.
Class1 equipment is defined as equipment where protection against electric shock is achieved by using basic insulation and also by providing a means of connecting the conductive parts that could become "live", if the insulation fails,to the protective earthing conductor in the fixed installation wiring.
Class1 equipment relies upon a satisfactory earth in the fixed installation , and connection to it, to ensure its safety. Portable Appliance testing of Class1 appliances only tests the integrity of the earth connection in the appliance and cannot test for the integrity within the fixed wiring. It is therefore also a requirement to have periodic fixed wiring installation tests.
Class II equipment is defined as equipment in which protection against electric shock is provided by basic insulation and additional supplementary or reinforced insulation. Commonly descibed as doubly insulated. These appliances do not rely upon installation conditions and should have no provision for protective earthing.
Class III equipment is defined as equipment that relies on supply from a SELV ( Safety extra low Voltage ) source to protect against electric shock.
JPS Calibration Services Ltd
13 St Giles Close
Wendlebury
Bicester
Oxfordshire
UK
OX25 2PZ
Tel +44 (0)845 17025 00
Fax +44 (0)845 17025 01
email enquiries@JPS-Cal.co.uk
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