Clause 3 – How to understand the definition of “thermostat”

thermostat: temperature-sensing device, the operating temperature of which may be either fixed or adjustable and which during normal operation keeps the temperature of the controlled part between certain limits by automatically opening and closing a circuit. The thermostat itself does not control the temperature, the thermostat senses the temperature and controls the temperature by switching…

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

detachable power supply part: part of the appliance the output of which is intended to be detachable from the class III construction part of the appliance.Note 1 to entry: Means of detachment are a flexible cord and connector or an appliance outlet fitted to the detachable power supply part. This actually defines a detachable adapter….

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

(IEC 60335-1 Ed. 5.1) battery-operated appliance: appliance deriving its energy from batteries enabling the appliance to perform its intended function without a mains connection.(IEC 60335-1 Ed. 6)battery-operated appliance: appliance deriving its energy from batteries enabling the appliance to perform its intended function without a supply connectionNote 1 to entry: A battery-operated appliance can have a…

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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…

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

small part: part, where each surface lies completely within a circle of 15 mm diameter, or a part where some of the surface lies outside a 15 mm diameter circle but in such a way that it is not possible to fit a circle of 8 mm diameter on any of the surfaces.NOTE A part…

Clause 3 – How to understand the definition of “tool”

tool: screwdriver, coin or any other object that may be used to operate a screw or similar fixing means. I’d like to explain the intent of the standard, which defines a separate tool, in order to distinguish between operations that use a tool and those that do not. For example, if a tool is used…

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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…