Is standard for creepage distance?

Asked by: Dr. Oren Aufderhar
Score: 4.2/5 (51 votes)

When designing a switch-mode power supply for use in information technology (IT) equipment, a typical rule of thumb is to allow an 8-mm creepage distance between primary and secondary circuits, and a 4-mm distance between primary and ground.

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Also asked, What is creepage distance?

Creepage distance means the shortest distance along the surface of a solid insulating material between two conductive parts. The values of table "Creepage distances to avoid failure due to tracking" are based upon existing data and are suitable for the majority of applications.

Also, How do you measure creepage distance?.
How to Determine Creepage Distance for Connectors
  1. Creepage Distance/Air Gap: The Path of Least Resistance. ...
  2. Check the Pins on the Connector Face. ...
  3. Check the Backside of the Connector: ...
  4. Check Female Contacts as well: ...
  5. Check For Hidden Creepage Paths Inside the Connector. ...
  6. Check for Hidden Creepage Paths Outside the Connector.


In this regard, Why is creepage distance important?

The isolation required between parts with different operating voltages, to prevent against unacceptable risk, is the primary reason for the importance of creepage and clearance distances. ... It [creepage] is the shortest distance between two conductive parts, measured through air.

How can creepage distance be improved?

Thinking back to the mountaintop metaphor, one way to increase creepage is to make a valley between the peaks. You can cut grooves or troughs into the PCB substrate to increase creepage. You can also sometimes cut slots all the way through the insulator to increase the distance.

24 related questions found

What is flashover distance?

Strike distance is simply the shortest distance between the end fittings of the insulator in the surrounding medium. It is also sometimes referred to as the dry arc distance, flashover distance, or tight string distance. ... The higher the operating voltage, the greater strike distance you will need.

What is current creepage?

Creepage is defined as the shortest distance between two conductive paths measured along the surface of a solid insulation. The shortest path is typically found around the end of the package body between conductive pins or leads.

What causes creepage?

This can include an accumulation of conductive contaminants that can become conductive with moisture (i.e. dust). This also includes periodic overvoltage events on the mains voltage. These events can be caused by a number of normal situations including weather and switching induced overvoltages.

What is creepage distance of bushing?

distance. Minimum nominal creepage distance is the shortest distance along the surface of an insulator between two conductive parts. In the case of bushings, this is the distance between the bushing top metallic dome/terminal and the flange, which is referred to in terms of mm/kV, Fig. 9 [1, 9].

What is tracking in electrical?

Tracking is defined as a process that produces localised irreversible deterioration on the surface of an insulator, resulting in the loss of the insulating function by the formation of a conductive path on the surface of the insulator.

What is creepage distance in surge arrester?

Creepage distance is the distance on the surface of the housing from high to low voltage end (see Fig. 4). This parameter is critical when an arrester is being applied in areas where there is salt, industrial or other contamination.

What is leakage distance?

Leakage distance is defined as the shortest path on the surface of an insulation material over which leakage current may flow.

What is creepage distance in disc insulator?

The creepage distance is an important parameter of the insulator that affects the safe operation of transmission lines. It refers to the shortest distance between two electrodes along the outer surface of the insulating member under a normal operating voltage.

What is basic insulation level?

Definition: A design voltage level for electrical apparatus that refers to a short duration (1.2 x 50 microsecond) crest voltage and is used to measure the ability of an insulation system to withstand high surge voltage.

What is dry arcing distance?

Dry arcing distance is the shortest distance outside the insulator along the air not along the insulator body and between those parts which normally have the operating voltage between them. ... Arcing distance is also called as flash over distance.

What is creepage distance Mcq?

MCQ: What is meant by Creepage Distance? ... Shortest distance between two conducting parts along the surface of the insulating material. Distance between ground and the highest earthed point on the equipment.

Why bushings are used in transformers?

The bushings used for the low voltage winding(s) of a transformer are often solid type with a porcelain or epoxy insulator. ... Their purpose is to control the voltage field around the center conductor so that the voltage distributes more uniformly across the surrounding insulation system in the bushing.

What is voltage creep?

Creepage or creep distance is pretty simple. ... It represents the shortest distance along the surface of the insulator between the conductive ends of the insulator. In a typical insulator application, one end would be at an elevated voltage level and the other end would be at a lower voltage or grounded.

What is PCB voltage?

Although power supply circuit boards are classified according to their output voltage and power. There is no universally accepted definition for high voltage; however, the generally accepted level for industrial circuitry is ≥ 100V (AC or DC).

What is electrical clearance?

The electrical clearance is the electrical isolation between two conductive components, whereas the creepage indicates the conduction of electricity across the surface of a nonconductive component. The clearance and creepage distance are two important parameters while designing an electrical assembly.

What is pollution degree?

Pollution degree is a classification according to the amount of dry pollution and condensation present in the environment. This classification is important since it affects creepage and clearance distances required to ensure the safety of a product. ... Temporary conductivity caused by condensation is to be expected.

What is protected creepage?

part of the creepage distance on the illuminated side of the insulator which would lie in shadow if light were projected on to the insulator at 90° (or 45° in special cases) to the longitudinal axis of the insulator.

What is minimum electrical clearance in PCB?

Under the IPC 2221 standards, the minimum PCB trace clearance (really, the clearance between any two conductors) is 0.1 mm for general purpose devices, or 4 mils. For power conversion devices, this minimum spacing is 0.13 mm, or 5.1 mils.

What is reinforced insulation?

The reinforced insulation is an improved basic insulation with such mechanical and electrical properties that, in itself, the insulation provides the same degree of protection against electrical shock as double insulation. ... The reinforced insulation has the same level of insulation just like a double insulation.