Hi Scott:
I have seen no safety standards or codes that specify which products must be Class I and which products must be Class II, except in the USA washers and dryers must be Class I. As far as I know, the decision is that of the manufacturer. I have been associated with a manufacturer who has made the same product both ways. In my case, one of the factors in deciding Class I or Class II was cost (e.g., a 3-wire cord was more expensive than a 2-wire cord). I suspect a major factor is “momentum” of the manufacturer: we made it this way last time, and we know how to do it this way. A product with a grounding (3-wire) power cord is a Class I product regardless whether it has no accessible conductive parts. Unlike a Class II product, a Class I product does not bear a marking attesting that it is Class I. Note that a Class I construction necessarily includes Class II construction, e.g., appliance inlet which is all-insulated. We ignore the Class II construction portions of a Class I product. I checked our electric kettle (which has accessible metal) and electric coffee-maker (which has the heater plate accessible metal). Both are 2-wire. Neither has the double-insulated symbol. Both are UL-certified. Best regards from beautiful snowy Bend, Oregon, USA, Rich From: Scott Xe <scott...@gmail.com> Sent: Tuesday, January 14, 2020 6:59 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] Class I vs Class II safety constructions In terms of safety level, both constructions are given the equivalent protection against electric shock. In electrical appliances, Class I is used most whereas Class II is employed in most electronic products. Is there any background for such design route? In some cases such as induction cookers, the enclosure is plastic/glass - no any internal metal part exposes to the outside surfaces. The product is not marked with a double square symbol and comes with a 3-pin plug. Why is this type of product not classified as Class II rather than Class I with the plastic/glass enclosure? Thanks and regards, Scott - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
