Hi group, I have a query on the understanding of the above section. I thought I fully understood it until I used a different lab for Product Safety Compliance testing (both accredited!).
We use a linear (basically a transformer with a PTC thermistor) class II SELV O/P stand alone power supply rated 10Vac, 5A. One of the labs tested the O/P Isc with a direct application of the sc. The other lab tested the O/P Isc by applying a load of 8A. The results were therefore interpreted differently. Isc (direct) = 30A falling to 0A within 30secs. Considered a PASS (8A for < 1min) Isc (8A load) = 8A for > 2mins. Considered a FAIL (8A > 1min) This has a crucial bearing on whether I need a fire enclosure or not for my all plastic enclosure! 1. What is the correct method to test for a Limited Power source in determining what enclosure is required? 2. If a fire enclosure was needed what is the minimum plastic rating i.e. 94V0, V1 or what? 3. I cannot put a 5A fuse in the product, the lab says that the overcurrent protective device must be outwith the non-fire enclosure in order to stop the non compliant energy source entering the enclosure. Is this correct? 4. Similarly, I cannot use a resettable fuse in the product to meet these requirements? 5. Does the PTC used in the power supply need to meet the IEC 60730-1? I would very much appreciate clarification on this matter. THANKS!! Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: [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: 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"
