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If the PCB is sealed with solid sealant, how to determine the creepage distance and clearance?

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…

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A question about functional insulation requirements at the ends of a current fuse

The following circuit diagram The current fuse in position F1 is usually connected in series with the line.The photos of the real thing are shown in the following two pictures, the left one is not labeled, the right one shows the location of the current fuse and some other basic information. In the diagram above,…

Clause 3 – How to understand the definition of “live part”

live part: conductor or conductive part intended to be energized in normal use, including a neutral conductor but, by convention, not a PEN conductorNOTE 1 Parts, accessible or not, complying with 8.1.4 are not considered to be live parts.NOTE 2 A PEN conductor is a protective earthed neutral conductor combining the functions of both a…

Clause 3 – How to understand the definition of “accessible part”

accessible part: part or surface that can be touched by means of test probe B of IEC 61032, and if the part or surface is metal, any conductive part connected to it.NOTE Accessible non-metallic parts with conductive coatings are considered to be accessible metal parts. There are some parts or surfaces in the appliance that…

How are the creepage distances and electrical clearances of PTC heating element surfaces determined?

We are discussing here the second structure of the PTC heating element, PTC heating element structure please refer to the explanation of its definition. How is the creepage distance of the functional insulation at the location of the red circle in Figure 1 determined? We all know that NOTE 1 of TABLE 18 section has…

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Clause 3 – How to understand the definition of “PTC heating element”

PTC heating element: element intended for heating consisting mainly of positive temperature coefficient resistors that are thermally sensitive and have a rapid non-linear increase in resistance when the temperature is raised through a particular range. As the temperature increases, the resistance of the heating element of the PTC heating element increases. The relationship between temperature…

A question about whether the second part of clause 21.2 needs to be tested.

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…