The emphasis here is on a part of the construction on the appliance, which can meet the requirements of double insulation or reinforced insulation. Therefore, a class I appliance will also contain a class II construction .Example: The oven shown in the figure below uses a metal shell and a plastic switch knob. When the…
class II appliance: appliance in which protection against electric shock does not rely on basic insulation only but in which additional safety precautions are provided, such as double insulation or reinforced insulation, there being no provision for protective earthing or reliance upon installation conditions. NOTE 1 Such an appliance may be of one of the…
class I appliance: appliance in which protection against electric shock does not rely on basic insulation only but which includes an additional safety precaution, in that conductive accessible parts are connected to the protective earthing conductor in the fixed wiring of the installation in such a way that conductive accessible parts cannot become live in…
class 0I appliance: appliance having at least basic insulation throughout and incorporating an earthing terminal but having a supply cord without earthing conductor and a plug without earthing contact. The appliance has a terminal for connecting an external protective conductor (protective earth conductor), but there is no wire for connecting the appliance to the protective…
class 0 appliance: appliance in which protection against electric shock relies upon basic insulation only, there being no means for the connection of conductive accessible parts, if any, to the protective conductor in the fixed wiring of the installation, reliance in the event of a failure of the basic insulation being placed upon the environment.NOTE…
protective impedance: impedance connected between live parts and accessible conductive parts of class II constructions so that the current, in normal use and under likely fault conditions in the appliance, is limited to a safe value. Case 1:The first case is usually some situations that require low-voltage power supply, such as adapter-powered products. The output…
functional insulation: insulation between conductive parts of different potential which is necessary only for the proper functioning of the appliance. Functional insulation is set because of the functional needs of the appliance. In electrical products, there must be conductive parts with different potentials (different voltages). If the voltage of all energized conductors in the product…
reinforced insulation: single insulation applied to live parts, that provides a degree of protection against electric shock equivalent to double insulation under the conditions specified in this standard.NOTE It is not implied that the insulation is one homogeneous piece. The insulation may comprise several layers which cannot be tested singly as supplementary insulation or basic…
double insulation: insulation system comprising both basic insulation and supplementary insulation The definition is only to simplify the description of basic insulation and supplementary insulation in the standard, using one name to descirbe two names. As shown in the figure below, the supply cord has two layers of insulation, the inner wire sheath and the…
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