Only non-conductive pollution occurs, except for occasional temporary conduction caused by expected condensation. For example, equipment, components, or subassemblies that excluded from dust and moisture through sealed packaging. No pollution or only dry non-conductive pollution occurs. IEC 62368-1 defines the different degrees of pollution that products exist in the operating environment: If it is an unknown material group, it is assumed to be IIIb. CTI is used to measure the electrical breakdown (tracking) properties of an insulating material. The material group is distinguished by the Comparative Tracking Index (CTI). The second layer of insulation independent of the basic insulation can protect the user from dangerous voltage when the basic insulation fails. The necessary insulation between the conductive parts in the equipment so that the equipment can operate normally so is not a safety consideration for users.Ī single-layer insulation system can reach the level of protection against electric shock equivalent to double insulation. Single-layer insulation can provide users with basic protection against electric shock.ĭouble insulation includes both basic insulation and supplementary insulation. Insulation type can be defined as standards for five different purposes: As described in IEC 62368-1, the creepage and clearance will be determined according to the following conditions: The creepage and clearance will have different considerations due to different factors such as product use conditions or environment. Creepage must be greater than or equal to clearance.Ģ.2 Important factor in determining distance.Creepage: The shortest distance between two conductors along the insulating surface.The shortest distance that can achieve insulated through the air. Clearance: In the "line of sight" distance or the shortest air path between two conductors.If the basic insulation fails, the external wires connect to the protective earthing conductor to conduct dangerous currents to the earth. In addition to basic insulation, it also includes additional protective measures. This type of equipment does not provide protective grounding, but itself can provide protection from electric shock. The equipment has protection against electric shock, in addition to basic insulation, there is supplementary insulation or provide reinforced insulation. There is no dangerous voltage, and this energy does not cause pain or injury. Classes of equipment with respect to protection from electric shock This article will focus on the clearance and creepage distance of electronic products.ġ. To achieve electric shock protection, electronic equipments must have an effective insulation method, which can be divided into clearance and creepage distance and solid insulation materials. This article is mainly aimed at preventing electric shock damage to the human body.
Safety standards have clear statements and regulations on manufactured equipment and parts to provide safe and high-quality products to end-users. Not only considered the normal operating conditions of the equipment, but also possible failure conditions, expected failure, and environmental influences such as temperature, altitude, pollution, and humidity. Students may need to sketch the final sample problem to recognize that it matches the image. Note that they could use the Pythagorean Theorem to solve all three problems, since that is where the labels on the image come from.Designers must understand the principles of safety requirements in order to design safe equipment. Similarly, the diagonal of a square divides it in half to match that image. Students may recognize the height of an equilateral triangle divides it in half to match the image. When she looks up at the top of the building, she measures the angle from the ground to the top of the building to be \(60^\). An engineer is standing 10 meters away from a building.The diagonal of a square is \(5\sqrt2\) units.The side length of an equilateral triangle is 8 units.Here are three sample problems to discuss: Ask students how they might decide what types of problems to use it on, and how they would solve those problems. If applicable, remind students that this type of image might be provided as a reference on standardized tests. Why are we looking at two triangles? Are the triangles related? What are we going to do with these?) Ask students what they notice and what they wonder about the images.
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