Hi Matthew:
According to IEC 60601-1 Sub-clause 6.2: ME EQUIPMENT energized from an external electrical power source shall be classified as CLASS I ME EQUIPMENT or CLASS II ME EQUIPMENT Its okay to have Class I equipment with Class II construction throughout. However, you are likely to find it unacceptable to authorities to use a protective earth cord without an internal connection. I suggest you run a PE wire from the appliance inlet to the metal tank or some other metal in the equipment - even though it is not needed as the equipment is double-insulated throughout. Best regards, Rich From: Matthew D. Varas <[email protected]> Sent: Tuesday, October 18, 2022 9:53 AM To: [email protected] Subject: [PSES] Confusion about IEC 60601-1-11 Power Cord Requirements and Functional vs Protective Earth Terminals Hello, We are converting a product to comply with 60601-1-11 for home use and I was hoping to get some clarification on the power cord requirements. The device is a mains-powered heating tank which uses snap-action thermostats to control mains power through the internal heating pad. It is currently intended for professional healthcare environments and has a metal tank that is treated as an applied part. A three-prong power cord is used to provide a protective earth connection as a MOP which, as I understand it, is not allowable per clause 6 of 60601-1-11 ("shall be class II or internally powered" and "shall not have a functional earth terminal"). The sales and marketing folks do not want to switch to a two-prong cord out of concern that it will look unprofessional when used in a professional healthcare environment, regardless of the fact that it will be redesigned to be double insulated through other MOP's. In trying to respond to them a coworker and I are in disagreement about how to interpret clause 6 and could use some help. Does this mean that : 1. The power cord must be two prong, or 2. The power cord can be three prong but can have the earth terminal not connected internally If it were to not be connected internally, I assume that a C18 connector on the device (while still using the three-prong cord) would be the correct path, however I interpret this to mean option 1 is correct. Which leads to the second related part of my question: I am unclear on the differences between a functional earth terminal and a protective earth terminal. After looking at Figure 2 in 60601-1, in this particular application it doesn't seem like there would be a difference between the two since it uses only mains power. Is this correct and can someone help me understand what the difference would be between the two, especially as it relates to home use? Thank you, Matthew Varas Electrical Engineer WR MEDICAL ELECTRONICS CO. direct 651.604.8473 | cell 763.222.6900 email [email protected] <mailto:[email protected]> follow wr medical Twitter <https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftwitter.c om%2Fwrmedical&data=04%7C01%7C%7C57c82b962a9e4c6dc35f08d8e56460ba%7C6dd45322 13424424b49f6ed32f836526%7C0%7C0%7C637511566569805805%7CUnknown%7CTWFpbGZsb3 d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000& sdata=JAFTd43d1%2FzmlmUwpHAW4Fr4oBdymQPfXBVZm7jgC6E%3D&reserved=0> | wrmed.com <https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.wrmed. com%2F&data=04%7C01%7C%7C57c82b962a9e4c6dc35f08d8e56460ba%7C6dd4532213424424 b49f6ed32f836526%7C0%7C0%7C637511566569815760%7CUnknown%7CTWFpbGZsb3d8eyJWIj oiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Lf oWjov5ngPlhGseN6fDmXIL7t1sLpzww5aI9DWghx4%3D&reserved=0> - ---------------------------------------------------------------- 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 <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html 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: Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
