Hi Steve:
I disagree with my colleagues. You didn’t say how the mains was distributed from the first module to the second and third modules. I have assumed the mains is also distributed by the Wago/Din rail scheme. If this is the case, then I would say the grounding can also be distributed by the scheme. The Wago, while not certified to 60204, has its grounding certified (by UL) to 60079. The grounding circuit need not be more robust than the mains circuit. Screw clamp pressure contact versus screwless pressure clamp… it’s the pressure (gas-tight contact) that counts, not whether or not the pressure is provided by a screw. According to my reading of one Wago/DIN spec sheet, the pressure is applied by a lever. Electrical contact is one parameter, mechanical integrity of the connection scheme is another parameter. A lock-washer provides mechanical integrity; it may provide electrical contact, depending on the construction scheme. I’m probably missing something here that shoots down my comments. (Fight FOR your client, not AGAINST your client.) Good luck, and best regards, Rich From: Steve Brody <[email protected]> Sent: Tuesday, June 18, 2019 11:39 AM To: [email protected] Subject: [PSES] Grounding HI all, I have a client with whom I am having a discussion about grounding for an EN 60204-1 product. The product consists of 3 sub-modules all of which use mains power derived from the first module where the external mains comes into the unit. In the first module the ground from the branch circuit goes to a ground stud, lockwasher and nut, and from there a ground wire goes from the stud to a DIN rail mounted Wago terminal block designed for grounds, as it is green/yellow in color, which is screwless and uses spring pressure to secure the wire in place. Other internal grounds in this module also connect to this block. The second module receives the main ground from the first module in a similar arrangement, and the third module gets it's ground from the second module. I have pointed out to my client that, in accordance with all safety standards I am aware of, and a figure in EN 60204-1 on grounds, that modules 2 and 3 must have ground leads that goes back to the point where the main ground comes into the unit originally, and not daisy chained from module to module. I don't think there is anyone who will disagree with this but I did say I would ask the question. Second question is do you thin there is a problem is using a screwless pressure connector for the grounds, as opposed to a stud/lockwasher/nut? Thoughts and comments would be appreciated by reply to his or privately at [email protected] <https://connect.xfinity.com/appsuite/[email protected]> - ---------------------------------------------------------------- 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 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
