Iec 60950 third edition, 199904 iec 609501, 2001 en 60950. Calculation of creepage discharge safety factors against the. A detailed overview of the calculation of the clearance and creepage distance is available as a download. In this paper, a relationship between the creepage distance of the insulator and sdd has been proposed. Pdf an online measurement method for insulator creepage. The empirical data gathered thus far has been used to develop the requirements for clearances and creepage distances as presented. Calculating creepage and clearance early avoids design. The period for the calculation of the effective voltage is for this reason at least the. At the same time, many measurement errors made during manual analysis. Supply voltage v acrms table 2 clearances, creepage and test voltage vpeak or dc overvoltage category ii vpeak clearance for reinforced mm creepage for reinforced mm test voltage. Creepage distances and clearances degrees of protection.
Ppc porcelain solid core post insulators and operating rods. If you want to learn more information about creepage distance for insulators, please visit orient power website. If the design distances are respected, the panel builder gets the guaranty of the performances to almost all types of over voltages and installation environmental constraints. As an example, a 15 pin highdensity dsub miniature connector has contacts on 0.
Creepage distance is also referred to as the leakage or creep distance. The protected creepage distance plus unprotected creepage distance is the creepage distance. Select the insulation, pollution degree, nominal ac mains, and enter the working voltage peak or dc, then click on the button to get the corresponding clearance in mm and mils. Specifically, creepage is the shortest distance between the path of two conductive parts of a medical device and is measures along the surface of insulation. The cumulative stress method in order to investigate the safety of a creepage distance, any selected path of desired length from the total creepage distance i. The minimum distance for creepage and clearance will depend on whether the design requires functional, basic, or reinforced isolation ratings. The second is surface creepage, or the distance across. However, instead of measuring distance in air, it measures the shortest distance along the surface of the insulation material. Application note coolmos electrical safety and isolation in. Board material and environment also affect creepage requirements. Research on insulator creepage distance measurement based on different. Clearances and creepage distances in lv electrical switchboards.
Typical creepage distances offered by silicon labs packages package nominal creepage mm creepage in air per iec60112 mm qsop16 3. Electronic band theory a branch of physics dictates that a charge flows if states are available into which electrons can be excited. The increased length is only measured down the groove to the point where it reduces to 1mm width. Of course, it is not the only standard that defines the electrical. Types of insulators edit a three phase insulator used on distribution lines, typically.
Iec608151986 iec600711199312 pollution level minimum nominal specific creepage distance1 mmkv2. Customers buy insulators and require the creepage distance, 900mm creepage distance polymer pin type insulator is used in south africa. Moisture or particulate accumulation on the board can shorten creepage. As reference value, in the worst case household appliance, for reinforced insulation between high voltage 220 vrms and low voltage creepage distance between tracks fig. Understanding creepage distances in compliance magazine. Understanding isolator standards and certification to meet. The greater the creepage distance, the higher the external safety protection. Clearance calculation in air insulated substations.
Jan 01, 2014 the term creepage refers to the abrupt junction of two, parallel insulating media. Iec 610101, edition 3 this changed in the third edition with a. Creepage is measured over the surface between the nodes. The creepage distance and surface characteristics determine the powerfrequency withstand of an insulator. Assuming pollution degree 2 and material group iiib, the required creepage distance for basic insulation would be 3. Pdf derivation of creepage distance in terms of esdd and. Calculation of creepage discharge safety factors against. Two methods have been utilized for the safety analysis of the creepage paths with nonuniform tangential electric elds. The indoor part inside the valve hall is 8327 mm long and has a flashover distance of 6720 mm and a creepage distance of 23,200 mm. Ipc2221 is generally accepted in electronic industry as a generic pcb design standard. The shortest distance may be through air air gap or along the surface of the insulation creepage distance.
It clearance is the shortest distance between two conductive parts, measured through air. Clearance calculator this program is based on table 2h of iec 60950. We will accomplish this by applying our very best technology, accuracy, value, proactivity, friendliness and dependability to our customers needs. Creepage distances and clearances degrees of protection i p 2 3 degrees of protection acc.
The level of component isolation rating required is determined by the end. Clearances and creepage distances in lv electrical. Implementation of standard iec 61439 socomec 3 socomec, a specialist manufacturer our range of products and services allows professionals working in the electricity sector to implement distribution and control gear assemblies that meet market requirements. The shortest distance between the high and low voltage points along the external insulating surface of an arresters weathersheds. A proper and adequate creepage distanceprotects against tracking, a process that produces a partially conducting. For 220 kv, the unified specific creepage distance of a surge arrester range approximately from 44 to 56 mmkv us1. The distance from a to b on the left side is part of protected creepage distance, and many a to b distances added on an insulator will form the total protected creepage distance. Leakagecreepage distance for surge arrestors electric. Study of creepage distance the contaminated insulator in. If you have a highdensity board, especially with high voltages, you need to be even more concerned. According to the existing jec 8 the required creepage for surge arresters of theses classes is. Pdf study of creepage distance of the contaminated. Application note coolmos electrical safety and isolation. In most electrical circuit connected to the ac mains supply, creepage distance is a concern.
For each calculated path segment between two points of contact, the software determines what proportion of the specification has been achieved. This can be done easily if the mathematical relationship between the creepage distance and salt deposit. The data of the cigre working group is given in terms of the withstand specific leakage or creepage distance in mmkv rms line to line voltage as a. Design engineers, especially printed circuit board pcb designers, are often not aware of the reasons for using creepage and clearance distances. Creepage requirements for medical applications analog. The connectors are the most likely place in a cable assembly where this path of least resistance exists. Clearance, creepage and other safety aspects in mysensors.
Creepage distance is the shortest distance separating two conductors as measured along the surface touching. What is the creepage distance and protected creepage distance. S bharadwaj reddy december 31, 2015 september 11, 2016 december 31, 2015 september 11, 2016. Clearance is the shortest distance between two conductive parts, or between a conductive part and ground, measured through air or other insulating medium.
Creepage distance of the insulated leakage path measured between the two points which define s. If no such states are available, the material is an insulator. Minimum required clearance according to ev 50107 in millimeter. Minimum creepage distances are 2025 mmkv, but must be increased in high pollution or airborne seasalt areas. Maintaining a certain creepage distance addresses the risk of tracking failures over lifetime. For reinforced insulation, the values for creepage distances are double the values provided in the table for basic. However, when it comes to distances between the pc traces, in my view, the ipc2221 table 61 stepwise limits are mostly baseless.
Ul 840 standard for insulation coordination including. Socomec, your best asset socomec is an independent manufacturing company specialising. Bus spacings in metalenclosed switchgear powell industries, inc. Abstract for design purposes, the specific knowledge about the creepage distance of the insulator for the contaminated environment is important. Creepage is along the surface, as the ant walks, and clearance is shortest distance, as the bird flys. Pdf study of creepage distance of the contaminated insulator in.
For example, a loose piece of solder could short out a pin carrying high voltage to another lowvoltage point in the circuit. Results are displayed as 3d graphics for better interpretation. This allows electrons to gain energy and thereby move through a conductor such as a metal. Pdf insulators play a crucial role in ensuring the normal operation of the. This path is above, not through, insulation and is measured in either air gap or creepage distance. All the required minimum distances throughout the whole substation can now be automatically determined based on the 3d substation model processed by the phase checker. Apr 28, 2020 creepage distance is a measurement that is commonly used in determining the conducting path of the flow of electricity. Iec 61439 suggests that the panel builders perform the routine verification for clearances and creepage distances. In this paper, a relationship between the creepage distance of the insulator and. Very heavy 31 1 for the actual creepage distance, the specified manufacturing tolerances are applicable. Creepage leakage distance 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. In the second edition of the 606011, the necessary air clearances and creepage distances were defined in a. I am just pointing this out just incase you are using creepage and clearance interchangeably, especially as you are referring to connectors and thus creepage may be what you are really interested in. These are the industry standard terms used to describe levels of voltage isolation performance and minimum safety requirements.
Clearance calculation in air insulated substations primtech. Mopp and moop in iec 606011 3rd mouser electronics. The following table gives for 888 v an interpolated creepage distance value of,32. In the manual process, a magnifying glass or microscope is used, in the automatic process a computer controlled camera and software based image analysis is. Image from here, along with some good reading material in practice, creepage and clearance on a pcb are the same initially. The insulation calculator will automatically determine the insulation.
Some researchers 1 have established the relationship between creepage distance and the sdd empirically. As always, the amount of it distances required for a given mode depends on the end system specification. The results of the creepage distance and clearance analysis is shown as a. Average and peak pressure 57 lets assume a circular contact patch, with a radius of 0. For example, a primary circuit to a primary circuit requires functional insulation. In general, this distance is dictated by the pollution degree of the environment in which the system will be used and the highest operating voltage present in the. Thus, according to the gaussian imaging formula, equation 1 is. When a medical device is developed, isolation between patient and mains voltage is a main concern. If a clearance is located remote from a creepage, and its distance is less than that of the creepage such that the clearance will break down at a lower voltage than the creepage, then what should be the requirement for the. When evaluating spacing, both clearance and creepage distances need to be addressed. Study of creepage distance of the contaminated insulator in. If it is less than 100%, the vulnerable path is highlighted in the analytics report. An online measurement method for insulator creepage distance on transmission lines article pdf available in energies 117. The purpose of the insulator or insulation is to insulate the electrically charged part of any equipment or machine from another charged part or uncharged metal part creepage leakage distance is the shortest path between two conductive parts mea.
In addition there exists an ammendmend a1 since 2012. Chapter 5 insulator design insulator,insulator manufacturer. Minimum creepage distances pollution degree printed wiring material voltage r. Jun 06, 2018 iec 61439 suggests that the panel builders perform the routine verification for clearances and creepage distances. Clearance and creepage are two very different things when talking about withstand voltage. Similar to clearance, creepage measures distance between conductors on a pcb. Clearance requirements in ehv ais substation you must respect. In addition, according to the iec 614391 section 10. Creepage distance for pcbs handling line voltage ac. Download pdf the international standard for medical safety equipment, iec 60601, covers electrical aspects of isolation components and differs from other standards in several respects, including creepage and clearance requirements and defibrillation tolerance testing. It is a particular junction such as that between solid and gaseous insulating media. Of course, it is not the only standard that defines the electrical clearance. 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. The results of the creepage distance and clearance analysis is shown as a percentage of the specified distance parameters.
In this guide you will find the information you need to design this system into a luminaire. Creepage distance for the avoidance of the failure by tracking download view the rating of clearance and creepage distances depends on the expected electrical surge, the characteristic values of the electronic protection measures as well as the contamination at the place of installation. Electrical insulation is the absence of electrical conduction. Applicable standards insulation, clearance, and creepage are in accordance with. Protected creepage distance of an insulator means 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 90or 45in special cases to the longitudinal axis of the insulator.
The minimum clearance distance up to installation heights of 2000 m above sea level is determined from the rated surge voltage and the pollution severity. The creepage distance of insulator can protect avoiding puncture and provide voltage protection. Dry arcing distance also called arc distance, and it means direct discharge distance, also you can refer the iec standard. Calculation of the clearance and creepage distance in accordance with vde iec and ul. Safety considerations and layout recommendations for. This edition covers the philips led linear driver on board dob family released for europe. Creepage distance an overview sciencedirect topics.
1291 1204 879 1221 900 843 662 1131 56 1412 487 532 496 593 1223 1277 1508 1281 1412 1463 886 424 232 1384 1386 552 395 157 1102 1444 1428 363 1420 235 108 395 1263 1146 1269 1314 1207