Hi, I would like to take up the point in the second paragraph of John's message with regard to the need to reliably connect a door to earth.
IEC 60601-1 specifies five methods for separating accessible parts from live parts in clause 17(g). The second method is "The accessible part is separated from live parts by a protectively earthed metal part, which may be a fully enclosing conductive screen". So, assuming that the door only touches earthed parts and cannot be touched by live parts in single fault conditions, then it would not be required to comply with the earth continuity test of clause 18. In this case additional earthing arrangements, beyond a hinge, are not required. Jon Griver http://www.601help.com The Medical Device Designers Guide to IEC 60601-1 From: "Crabb, John" <[email protected]> To: "Ned Devine" <[email protected]>; "IEEE EMC/Product Safety (IEEE, EMC/Product Safety)" <[email protected]> Sent: Friday, November 14, 2003 7:00 PM Subject: RE: Grounding > > 2.6.1 of IEC 60950-1 refers to "parts of equipment shall be reliably > connected to the main protective earthing terminal". A hinge would > certainly not be regarded as a "reliable connection". > > As far as your door is concerned, is there any single insulated hazardous > voltage wiring likely to contact it, or any other single faults which would > cause the door to assume a hazardous voltage ? > If not, it could be debated that it doesn't require to be grounded. > > Regards, > John Crabb, (Product Safety) , > NCR Financial Solutions Group Ltd., Discovery Centre, > 3 Fulton Road, Dundee, Scotland, DD2 4SW > E-Mail :[email protected] > Tel: +44 (0)1382-592289 (direct ). Fax +44 (0)1382-622243. > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Ned Devine > Sent: 14 November 2003 15:29 > To: IEEE EMC/Product Safety (IEEE, EMC/Product Safety) > Subject: Grounding > > > > Hi, > > I need some help. I told someone that you can not depend on mechanical > contact only (i.e. in this case a door hinge) for protective earth. Even if > it passes the test, it would still not be acceptable because it does not > meet the construction requirements. He then asked me to show him were it > said that in the standard (IEC 60950-1 or IEC 60601-1). I looked and could > not find it. Am I just missing it, or is it not in the standards? > > There is a reference in CSA standards to C22.2 No. 0.4 that has the > requirement, but I can not find a similar reference in UL or IEC standards. > > > Ned Devine > Program Manager III > Entela, Inc. > 3033 Madison Ave. SE > Grand Rapids, MI 49548 > > Phone: 616 248 9671 > Fax: 616 574 9752 > e-mail: [email protected] > www.entela.com > 1-800-888-3787 > Web: www.entela.com > Grand Rapids * Detroit * Boston * Toronto * Taipei 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] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
