Brian, There are a couple of things that you might try: 1) Modify your PCB outline to rout a channel between the contacts and coil. This would have to be cut completely through the PCB board, so any internal planes would need to have clearance added first. I have seen this done successfully with opto-isolators that did not meet creepage spacings.
2) Use a high-voltage epoxy compound to add insulation around the relay pins. This reduces the potential at the PCB surface. It would have to be added post-solder. Another less pleasant option is to add extension leads to the relay, insulate with high- voltage epoxy, and then bend the exposed portion of the leads to match the PCB holes which would have the correct spacing. The main advantage over method 2 is the ease of replacing the relay (no epoxy on the PCB). I would ask the relay vendors for advice. You cannot be the first customer to have encountered this issue. Scott Lacey On 10 Dec 2002 at 15:33, [email protected] wrote: > > Happy Holidays Group, > > Let me set the scene for you: > > We have a piece of laboratory equipment that has a 10,000 volt low > current power supply that puts a high potential onto a small metal > sample as it is being tested. When the operator opens a door to > remove the sample we have to turn off the high voltage to protect the > operator. > > We have been looking for a High Voltage Relay to do the job without > luck. We have found several that are rated for 10,000 volts, but the > creepage and clearance spacing between the pins don't seem to match > what the IEC61010-1:2001 standard says. > > If I am reading the standard correctly, the creepage is the big > problem. Table 7 calls for a spacing of 40mm on pc cards pollution > degree 1. This seems like a lot. The clearance would be 30.3mm - > 31.6mm according to Table 5. We have one relay that is rated 10,000 > volts, but it only has 23mm between the contact and the coil pins. > How can this be? Am I looking at something wrong here? > > I can't find any high voltage relays with any kind of agency > approvals. > > 1. Am I figuring out the creepage distance correctly or am I missing > something? > > 2. If I do have to meet the spacings listed above, does anyone know of > a good source for a compliant relay? > > 3. Anyone have tips and suggestions how to minimize spacings in high > voltage circuits? > > Thanks to all. > Brian Kunde > LECO Corp. > > ------------------------------------------- > 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: > Ron Pickard: [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: > http://ieeepstc.mindcruiser.com/ > Click on "browse" and then "emc-pstc mailing list" ------------------------------------------- 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: Ron Pickard: [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: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
