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…

A question about clause 21.1 and detachable parts

21.1 Appliances shall have adequate mechanical strength and be constructed to withstand such rough handling that may be expected in normal use.Compliance is checked by applying blows to the appliance in accordance with test Ehb ofIEC 60068-2-75, the spring hammer test.The appliance is rigidly supported and three blows, having an impact energy of 0,5 J,…

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

detachable part: part that can be removed or opened without the aid of a tool, a part that is removed or opened in accordance with the instructions for use, even if a tool is needed for removal, or a part that does not fulfil the test of 22.11.NOTE 1 If for installation purposes a part…

Clause 3 – How to understand the definition of “non-detachable part”

non-detachable-part: part that can only be removed or opened with the aid of a tool or a part that fulfils the test of 22.11. The definition of this concept is mainly for the judgment of clause 8 and clause 20, and the judgment of other clauses may also be used. On the appliance, whether any…

Clause 3 – How to understand the definition of “combined appliance”

combined appliance: appliance incorporating heating elements and motors. We know that this standard mainly protects against the following five types of dangers, which are electric shock, mechanical damage from moving parts, thermal damage (such as burns), fire damage, chemical and biological damage. Generally speaking, thermal damage is caused by electric heating elements, and mechanical damage…

Clause 3 – How to understand the definition of “motor-operated appliance”

motor-operated appliance: appliance incorporating motors but without any heating elementNote 1 to entry: Magnetically driven appliances are considered to be motor-operated appliances. Household electrical appliances usually use heating elements or motors to complete their designed functions. The main functions are heating, such as heating food or air, and rotation or mechanical movement of products, such…

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

heating appliance: appliance incorporating heating elements but without any motor. Before introducing this definition, we need to briefly introduce the electric heating elements commonly used in household electrical appliances. PTC heating element: PTC (Positive Temperature Coefficient) heating elements are widely used for various heating applications because of their self-regulating properties and safety features. Here are…