Hi all, John Crabb asked me about my previous response (see below). He brings up some points that I don't have experience with. I wasn't sure how to answer it. I was hoping that someone else could address his concern.
For our AC powered equipment, we have never needed to add varistors, MOV's, sidactors, TVS's ... to the AC mains for surge protection. The existing input filter (which carries its own safety approvals) has been sufficient. So... I have never run into the component restriction that John points out below. If anybody else has, maybe they could address John's question better than I? However, we have used Sidactors, TVSs and/or MOVs on signal lines and Telecom lines with good results. The only major problems that we have had are due to mismatch between power dissipation specs for a fuse and MOV in a telecom circuit. There were some instances where the MOV would burn before the fuse would blow during "power cross" testing. Chris > -----Original Message----- > From: Crabb, John [SMTP:jo...@exchange.scotland.ncr.com] > Sent: Tuesday, November 20, 2001 12:13 PM > To: Chris Maxwell > Subject: RE: Methods & Equipment; Surge & Dips > > Chris, we have been considering using Harris (Littelfuse) > LA series varistors to overcome a surge problem, but it is > being highlighted to us that there is a CENELEC > "OSM Decision" that several European countries do not > accept the use of varistors between the mains and the > protective earth. > > Have you ever come across this restriction, and if so, how > did you get round it ? > (I gather UL and CSA have no such concerns). > > Regards, > John Crabb, Development Excellence (Product Safety) , > NCR Financial Solutions Group Ltd., Kingsway West, Dundee, Scotland. > DD2 > 3XX > E-Mail :john.cr...@scotland.ncr.com > Tel: +44 (0)1382-592289 (direct ). Fax +44 (0)1382-622243. > VoicePlus > 6-341-2289. ------------------------------------------- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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.
