Answer / raj

To identify the creepage distance

* Define the installation category
* Define the degree of pollution expected
*From the nominal voltage and the type of supply system
select the rated voltage from table 00.03 a/b
*From the rated voltage and degree of pollution select
the minimum creepage required in table 00.04

For the dimensioning of the creepage distance the tracking
formation of the insulating material has to be considered.
If not indicated contrary, the CTI value of the insulating
material is <400 and the isolation group

Answer / deadzg_devil

Creepage Distance. Creepage is the shortest path between two conductive parts (or between a conductive part and the bounding surface of the equipment) measured along the surface of the insulation. A proper and adequate creepage distance protects against tracking, a process that produces a partially conducting path of localized deterioration on the surface of an insulating material as a result of the electric discharges on or close to an insulation surface. The degree of tracking required depends on two major factors: the comparative tracking index (CTI) of the material and the degree of pollution in the environment. Used for electrical insulating materials, the CTI provides a numerical value of the voltage that will cause failure by tracking during standard testing. IEC 112 provides a fuller explanation of tracking and CTI.1 Tracking that damages the insulating material normally occurs because of one or more of the following reasons:

*
Humidity in the atmosphere.
*
Presence of contamination.
*
Corrosive chemicals.
*
Altitude at which equipment is to be operated.

Answer / k.prakashchandra

The above answer is correct. You can take it as the shortest
path between conductive parts including bounding
surface,measured along the surface of the insulation

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