Creepage distance is a measurement that is commonly used in determining the conducting path of the flow of electricity. The term creepage itself has to do with determining the distance between the point of origin and the point of termination along the surface of the insulation used to protect the wiring used in conducting the electrical flow. This type of measurement is essential in assessing the impact of the flow of current on the insulation, especially in terms of how quickly a certain level of current will result in damaging the insulation to the point that it no longer offers adequate protection. The deterioration, known as tracking, is key to determining what type of insulation is best under various conditions, including humidity and altitude.
The idea behind determining the creepage distance is to identify the distance between the two conductive parts that may exist and still keep the rate of deterioration within reasonable limits. This measurement is also sometimes known as the clearance distance. Along with considering the amount of power that is carried between the two points, factors such as the humidity in the general area and the possible presence of contaminants that could weaken the insulation and cause corrosion to the wiring are also important factors. Taking the time to consider these factors makes it easier to choose insulation materials that are more likely to hold up well under specific conditions and maintain the efficiency of the machinery relying on the wiring as a power source.
A safe voltage creepage distance will vary, based on the type of equipment involved, the insulation that protects the wiring, and the amount of current that is conducted through that wiring. Different grades for wiring are used throughout the world to carry current safely from a power source to the devices that require the current flow to operate. By utilizing the most appropriate gauge of wiring and insulation, and allowing for external factors like humidity, it is possible to establish a means of conducting current with relative safety, while also ensuring that the flow remains more or less consistent. This in turn helps to minimize the chances of damaging equipment on the receiving end, either from providing an inadequate amount of power or causing frequent power surges that overload the receiving circuits.
Creepage distance standards will vary somewhat based on the application involved and the type of current that is conveyed along the wiring. Most nations have safety standards that are based in part on the responsible determination of electrical creepage distance, and make use of various methods to monitor and certify wiring contained in devices or used in various electrical grids and systems to control the flow of current. Inspection of electrical devices and systems from time to time makes it possible to identify any unusual rate of deterioration and make replacements on an as-needed basis.
By Malcolm Tatum