functional insulation as well as other insulation exists on circuit boards. Typically, the surface environment of a circuit board is determined to be either Pollution degree 3 or pollution degree 2.If the circuit board is mounted in an electrical box and sealed with a solid sealant, the sealing will look as follows: What should be…
We know that clause 29.3.2 and clause 21.2 are two separate clauses and they are not very much related, which means that the product being assessed needs to fulfill both clauses if applicable.A reinforced insulation system consisting of three separate layers of insulating material or what could be considered a double insulation system, Each layer…
safety isolating transformer: transformer, the input winding of which is electrically separated from the output winding by an insulation at least equivalent to double insulation or reinforced insulation, that is intended to supply an appliance or circuit at safety extra-low voltage The transformer mentioned here is used to supply power to appliances or circuits. Most…
safety extra-low voltage: voltage not exceeding 42 V between conductors and between conductors and earth, the no-load voltage not exceeding 50 V When safety extra-low voltage is obtained from the supply mains, it is to be through a safety isolating transformer or a convertor with separate windings, the insulation of which complies with double insulation…
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 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…
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…
There is a note in table 17 and table 18 as “For working voltages > 10 V and ≤ 630 V, if the voltage is not specified in the table, the values of creepage distances may be found by interpolation.”. If the operating voltage is not the value listed in the table, then we usually…
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