And in some cases we have found that routing a slot in the board between traces is the most effective way to cram more stuff in a smaller package and still pass Hipot testing and TÜV creepage and clearance requirements. Phil -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Brooks,Bill Sent: Thursday, October 06, 2005 12:02 PM To: [log in to unmask] Subject: Re: [TN] Highvoltage testvoltage Marcel, That particular section of the IPC-2221 spec refers to the insulation resistance across the surface and through the board material. If you are planning on passing a test with 2100 volts peak to peak you need to calculate a minimum spacing something like this to pass. For internal conductors - .25mm plus 4mm = 4.25mm plus mfg tolerance For external conductors uncoated, sea level to 3050m - 2.5mm plus 8mm = 10.5mm plus mfg tolerance And so on... Just find the condition that you expect the board to survive in and make sure that your spacing between conductors is greater than the minimum number you come up with by calculating the voltage spacing from that table. In your case the minimum spacing on the outside surfaces would be 10.5mm. If you expect to meet that minimum, you mist add the manufacturing tolerances into your equation before coming up with the nominal spacing you will design the board with... I would design based upon passing the test voltage, otherwise you will not pass the test and designing to the 'working' voltage doesn't help you. Note that the conformal coatings can reduce the spacing needed, however they indicate that you should not depend upon the coatings as a way to prevent voltage breakdown, obviously the coatings are not reliable under all circumstances as an insulator and the coating thickness varies greatly... they only protect the surface of the board and components from contamination from dirt, humidity and/or any conductive materials in the environment being deposited between the two voltage extremes and providing an ionic path for voltage break over. Avoid sharp corners on traces or pads or features in copper in between the 2 voltage extremes... electrical arcing tends to form at the sharp points... Clean boards have a much better chance of passing the electrical test, once an ionic path has formed through any contamination... it's all over. Note that these are minimum spacings... If you are trying to pass a safety agency test, you may be required to use greater spacing to qualify. For example TUV has more stringent requirements than the minimums stated in Table 6-1 in IPC-2221. Best regards, Bill Brooks - KG6VVP PCB Design Engineer, C.I.D.+, C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 Datron World Communications, Inc. _______________________________________ San Diego Chapter of the IPC Designers Council Communications Officer, Web Manager http://dcchapters.ipc.org/SanDiego/ http://pcbwizards.com -----Original Message----- From: Marcel van den Berk [mailto:[log in to unmask]] Sent: Thursday, October 06, 2005 4:58 AM To: [log in to unmask] Subject: [TN] Highvoltage testvoltage Dear Technet-ers, We, at development ASML, have some discussions and questions about the interpretation of chapter 6.3 electrical clearances and in particular for highvoltage (700Vac). Question regarding to IPC-2221 : 1) Are the electrical conductor spacings as mentioned in table 6-1 based on a testvoltages ? (for example 2100V testvoltage) 2) Must i design , my board, on the testvoltage (2100V) or on the working voltage ? 3) Is there a relationship between IPC-2221, 6.3 and the IEC60950 ? and if "yes" where can i find this relationship? 4) Can i use the same highvoltage rules for Flex-boards? Is there anyone how can help me? , thanks in advance. Best Regards, ------------------------------------------------------------------------ ---- Marcel van den Berk DFM Support / PCB Technology / Board layout Electronic DEVelopment------------PRoduction Standards group A.S.M.L. De Run 6665 p.o.box 324 5504 DT Veldhoven The Netherlands E-mail: [log in to unmask] Internet: http://www.asml.com <http://www.asml.com/> ------------------------------------------------------------------------ ---- -- The information contained in this communication and any attachments is confidential and may be privileged, and is for the sole use of the intended recipient(s). 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ASML is neither liable for the proper and complete transmission of the information contained in this communication, nor for any delay in its receipt. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------