This is a great discussion. It took some work to get most of the world to use a solid, direct earth/ground connection in cabinets and equipment. CSA published detailed connection diagrams and pushed direct connection into many product standards with good results. The struggle has been since the modularization of components and units has come into play. This raises questions as to how to interconnect everything together in a way that preserves the integrity of the earthing/grounding connection when it is a principle safeguard against electric shock. As an OF (= Old Fellow, in polite company) I prefer that the earth/ground wire be tied to the mechanical structure of the cabinet or equipment first then carried to the distribution components. It is very difficult to destroy the integrity of this earthing first philosophy. There are many scenarios where the quick install/quick connect terminal block can be disconnected from the earthed rail and leave the cabinet/equipment without the needed earthing/grounding connection. Let's keep the focus on providing the highest integrity protection scheme in place (and common practice).
:>) br, Pete Peter E Perkins, PE Principal Product Safety & Regulatory Affairs Consultant PO Box 1067 Albany, Ore 97321-0413 503/452-1201 IEEE Life Fellow <mailto:[email protected]> [email protected] Entropy ain't what it used to be From: John Woodgate <[email protected]> Sent: Monday, September 23, 2019 4:19 AM To: [email protected] Subject: Re: [PSES] Grounding of metal cabinet The question is how the cabinet is earthed if the PE wire goes to a terminal block. If a wire comes out of the terminal block to a stud on the cabinet, that is less reliable than a solid connection. I suggest you take the advice. It doesn't apply if the 'terminal block' is not an insulating block with metal inserts but a metal block firmly attached to the cabinet. Best wishes John Woodgate OOO-Own Opinions Only J M Woodgate and Associates www.woodjohn.uk <http://www.woodjohn.uk> Rayleigh, Essex UK On 2019-09-23 11:33, Amund Westin wrote: A flexible 1-phase AC cable is entering a metal cabinet and the PE-wire is directly connected to an Earth terminal block (green/yellow). Some years ago, a safety engineer told me that the earth wire should first be connected to a ground stud inside the cabinet via a lug terminal climp and fastened with a nut. From the stud, a green/yellow wire should connect to the Earth terminal block. I thought it's OK to go directly to the Earth terminal block, right? . BR Amund Westin - ---------------------------------------------------------------- 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] <mailto:[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) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected] <mailto:[email protected]> > Mike Cantwell <[email protected] <mailto:[email protected]> > For policy questions, send mail to: Jim Bacher <[email protected] <mailto:[email protected]> > David Heald <[email protected] <mailto:[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] <mailto:[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) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected] <mailto:[email protected]> > Mike Cantwell <[email protected] <mailto:[email protected]> > For policy questions, send mail to: Jim Bacher <[email protected] <mailto:[email protected]> > David Heald <[email protected] <mailto:[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]>
