Drm is included at the request of the publisher, as it helps them protect their by restricting file sharing. This application note details the creepage and clearance requirements of an isolator type component, such as a digital isolator, used to provide protection from. Isolation means that no direct electrical connection, or conductor, exists between two or more circuits or between circuits and accessible parts. If you have a highdensity board, especially with high voltages, you need to be even more concerned. V mm 25 32 40 50 63 80 100 125 160 200 250 320 400 500 630 800 this voltage is for functional insulation, the working voltage, for basic and supplementary insulation of the circuit energized directly from the supply mains see 4. Creepage is along the surface, as the ant walks, and clearance is shortest distance, as the bird flys. The protected creepage distance plus unprotected creepage distance is the creepage distance. Pdf an online measurement method for insulator creepage. The following table gives for 888 v an interpolated creepage distance value of,32 mm. Image from here, along with some good reading material in practice, creepage and clearance on a pcb are the same initially. In order to read a secure pdf, you will need to install the fileopen plugin on your computer. For reinforced insulation, the values for creepage distances are double the values provided in the table for basic. Clearance, creepage and other safety aspects in mysensors.
Autocrear provides a robust and efficient softwarebased analysis of creepage and clearance. Package mosfet coolmos p7 and ce sj mosfet in to220. This is one of the most important parts by knowing your isolation grouptype you need to have for safety you enter this into the creepage calculator to get your creepage distance. Thus, it reduces system cost by offering an alternative to frequently used approaches to increase creepage distance. Indoor voltage in kv phase to earth in mm phase to phase in mm 0. The period for the calculation of the effective voltage is for this reason at.
Thus, according to the gaussian imaging formula, equation 1 is. Creepage is the linear surface distance from a live part to ground. Electrical safety and isolation in high voltage applications infineon. The to220 fullpak wide creepage package meets the requirements of open frame power supplies without additional measures. Ul840 insulation coordination including clearances and creepage distance for electrical. Clearance and creepage distance the following picture explains how to measure the distance between two metal parts. Pcb creepage and clearance requirements from around the world on. Free fall distance 24 deceleration distance 42 harness stretch 12 safety factor 24 total fall distance. Notice that since this is the total surface distance between the conductors, it is considerably longer than the clearance distance of the same contacts. Fall clearance calculation using an srl before fall free fall ffd hs dd sf cr post fall ah. The creepage path follows the contour of the groove.
Based on over 5 years of research, it features novel stateoftheart algorithms to handle the highly complex metrics of creepage and clearance paths and is capable of processing even large assemblies. Calculation of creepage discharge safety factors against. The shortest distance along a solid insulation surface between two conductive parts. Pdf insulators play a crucial role in ensuring the normal operation of the power system. The required minimum clearance were based on ul609501 standard, table 2n. Secure pdf files include digital rights management drm software.
Iec 60050 international electrotechnical vocabulary. This increases the creepage distance to the perimeter of the slot rather than the diameter. Ht insulators have stacked skirt or bell shapes to prevent dirt and dust from forming a conductive path across the insulator. These standards dictate both the working voltage require ment and the creepageclearance distance spacing necessary to deem an end product safe for end. Clearance calculator this program is based on table 2h of iec 60950. Problems with clearance and creepage distances are avoided. What is meant by creep distance in insulator design. Pcb creepage and clearance requirements from around the.
Therefore, a method has been developed based on the cumulative stress characteristics 12 that. Dry arcing distance also called arc distance, and it means direct discharge distance, also you can refer the iec standard. Research on insulator creepage distance measurement based on different photographic equipment. Its quite common to see a routed slot in a pcb underneath things like optocouplers and transformers used for isolation. Information and technical guidance for applications above. Design engineers, especially printed circuit board pcb designers, are often not aware of the reasons for using creepage and clearance distances. Since there are engineers from all over the world and from all different industries here, i thought it would be interesting to hear what you guys use as far as creepage and clearance rules in your pcb designs and why. Fall clearance calculation using an srl gorbel inc.
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. A special consideration is required symmetry in both the leakage inductance and dc. The clearances for air and creepage surface will usually be different. Typical connector body and contacts demonstrating the creepage distance. Note that generally all ipc documents are voluntarily rather than. Figure 2 typical connector body and contacts demonstrating the creepage distance clearance connector body effective creepage distance creepage connector body. 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. The required minimum clearance were based on ul609501. Minimum creepage distances pollution degree printed wiring material voltage r. Minimizing the leakage inductance on a pushpull converter design could be a big problem. Chapter 17 winding capacitance and leakage inductance. Creepage is the distance between the edges of the lead connections at the surface of the pcb.
The pull effect pulls the wire into the terminal point. It represents the shortest distance along the surface of the insulator between the conductive ends of the insulator. An online measurement method for insulator creepage distance on. Clearance space through the air creepage distance space over the surface. Calculating creepage and clearance early avoids design. Assuming pollution degree 2 and material group iiib, the required creepage distance for basic insulation would be 3. According to the existing jec 8 the required creepage for surge arresters of theses classes is.1549 1321 1514 315 654 1458 1055 1632 1536 1327 441 197 70 889 946 1413 524 326 197 877 646 606 957 829 812 308 1361 1127 732 867