Hi Rick, I am not sure what standard you are referencing, but regarding PCB things are moving. Currently the EN 61010 (lab and measuring / process control) allows for reduced creepage and clearance down to 1.5 mm for 230 Vac (on PCB) if can be shown the enclosure complies with IPx5 or better. It is formulated like you suggested, the pollution degree can be improved to 1 when the enclosure passes the IPx5 test. IPx5 is a rather innocent water spraying test using 12 litres per minute sprayed onto your equipment from 3 meters distance.
If you are involved in LVD approval, you might reference to this standards clause for other equipment too, if you decide to use "no standards" route. I suggest however, if you decide to do that that you ask a statement of opinion from a Notified Body for electrical safety. Gert Gremmen -----Original Message----- From: [email protected] [mailto:[email protected]]On Behalf Of [email protected] Sent: donderdag 31 januari 2002 21:01 To: [email protected] Subject: Pollution Degree vs. Creapage Distance I am wading through the creapage and clearance requirements for secondary circuits using the values in tables 5 and 6. It becomes very apparent that the creapage distances become quite large when you assume material group IIIb (CTI). For operational insulation, this might be 2-3X the clearance values. My question to the group is: Does the application of a solder mask allow for a change from pollution degree 2 to pollution degree 1? I understand that conformal coating requires significant testing when used to reduce spacings per table 7, but in this case I am only asking if solder mask can be used to improve the pollution concern. Assuming this is NOT the case, are there any other practical suggestions? Cutting slots in multilayer cards is a bit tricky. I can live with 0.7mm of clearance, but 2.5 mm (operational) or 5.0 (reinforced) of creapage is a bit difficult on a densely populated power supply. One last question. Why are the secondary circuit spacing requirements based on a primary input voltage? Thanks Rick Busche E&S [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
