Martin, The best design method in case of a mains ground failure is to design your equipment to meet double or reinforced insulation throughout. That means your equipment will still be considered a Class I product but you have designed it to meet the more stringent requirements for double or reinforced insulation to the normally reliably earthed parts.
For your info, some Class I switching power supplies meet the double or reinforced insulation between primary and earth and between primary and SELV circuitry. Please also be advised that some Nordic countries customers may require you to design your Class I equipment to meet the double or reinforced insulation requirements between parts where normally basic insulation is all that is required. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 -----Original Message----- From: marti...@appliedbiosystems.com [mailto:marti...@appliedbiosystems.com] Sent: Thursday, May 31, 2001 12:25 AM To: emc-p...@majordomo.ieee.org Subject: Secondary Grounding Group, This is a general product safety question: In order to avoid test failures during a single fault condition where the primary ground is removed, what design methods can be used to add a second ground to the system so that a ground is still provided even during a single fault condition of removing the primary ground? All responses are appreciated. Regards Joe Martin EMC/Product Safety Engineer Applied Biosystems marti...@appliedbiosystems.com ------------------------------------------- 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: http://www.rcic.com/ click on "Virtual Conference Hall," ------------------------------------------- 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: http://www.rcic.com/ click on "Virtual Conference Hall,"
