Interesting that North America code generally has 'polarized' connectors for Class II stuff, and all ANSI/CSA standards scoped for NFPA70/CSA C22.1 (at least ones that for employer's products) require touch/leakage current to be measured both L/N normal and L/N reversed.
DP input switch for both class I and II construction is normative for my stuff that connects to AC mains. Brian From: Pete Perkins [mailto:00000061f3f32d0c-dmarc-requ...@ieee.org] Sent: Monday, January 30, 2017 11:32 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Double Pole Mains Switches, Cord Connected Products Scott, Mike et al, The single pole switch is intended to be in the line side of the input power; in the case where the polarity is reversed, the emc components can be powered with line voltage on both Line and Neutral side increasing the electric shock touch current and protective conductor current. Safety standards need to specify testing in both Normal and Reverse polarity to ensure that the touch current and/or protective current is still within the limits specified under this condition. Use of a double pole switch ensures that this doubling of the touch current from the emc filter doesn’t happen. This same condition occurs with a single fuse in one pole of the input circuit. :>) br, Pete Peter E Perkins, PE Principal Product Safety & Regulatory Affairs Consultant PO Box 23427 Tigard, ORe 97281-3427 503/452-1201 p.perk...@ieee.org From: Scott Xe [mailto:scott...@gmail.com] Sent: Monday, January 30, 2017 5:51 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Double Pole Mains Switches, Cord Connected Products Some national plugs may not be reversible but those countries also widely acceptable to 2-pin Europe plugs or 3-pin Schuko plugs that are reversible. The safety standards do not need DPDT switch in compliance. Even though the single pole is not restricted to be on the live wire. Thus the switch on neutral wire is still considered acceptance. Needless to say, single pole switch on live wire and DPDT switch are considered the best practice in safety perspective. As I see less and less this practice is implemented in the latest products due to no support from harmonised safety standards. Regards, Scott From: Mike Sherman ----- Original Message ----- <msherma...@comcast.net> Reply-To: <msherma...@comcast.net> Date: Sunday, 29 January 2017 at 12:16 AM To: <EMC-PSTC@LISTSERV.IEEE.ORG> Subject: [PSES] Double Pole Mains Switches, Cord Connected Products Because of the lack of polarization on many 2 pin European plugs, I have always recommended double pole mains switches on cord connected products for the EU market. However, I am not finding support for this in standards such as 60335-1, 60601-1 or 62368-1. Your thoughts will be appreciated, oh experienced group, on: --safety issue involved --standards that do require double pole (sometimes referred to as "all-pole") mains switches. Mike Sherman Graco Inc. - ---------------------------------------------------------------- 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>
