Re: Shielded power cord, seeking source for
Hi Tim. You wrote: If screened mains cable is used, then surly it acts like a coax (a poor one possibly) and transfers the energy, contained within, to a point where the cables are not shielded. This would probably be at the mains wall socket - where the energy could (would?) then radiate! If the intention is not to cause interference to radiocommunications etc. then how has the screened mains cable helped? The test might seem OK but how is due diligence served? My problems have been that filters are often guilty of resonances at particular frequencies, providing substantial gain rather than attenuation. With 'white noise' things like phase angle controllers in the box, these filters put (in one instance) 32MHz out on to the mains cable, which radiated beautifully. The screen was sufficient to drop those emissions by about 15dB, thereby bringing it back into compliance. The transmission line characteristics of screened three core cable are very poor, and the conducted emissions of the 32MHz past the mains lead were clearly very much reduced by the inductance/capacitance of the cable, in that the -15dB results were perceived. The radiated emissions included those from the mains supply to the equipment. The mains cable on this thing was 3 metres long, and made up from component's, not moulded. The screen was grounded at the Supply end. Interesting stuff... Chris Dupres Surrey, UK.
Re[3]: Shielded power cord, seeking source for
Thank you, Jim, for this background. FCC Rules Part 15 state that if any such preventive measures are taken, the user should be advised and/or shielded cords must be provided with the equipment. I always feel very uncomfortable when standards are written in such a way as to arbitrarily prohibit the usage of certain equipment or parts. I am pleased to see that this is not the case here. The fact that the use of shielded cords and cables may not be the best EMC practice should not be transformed into another fact that shielded cords are not allowed. Tania Grant, Lucent Technologies, Octel Messaging Division tgr...@lucent.com __ Reply Separator _ Subject: Re[2]: Shielded power cord, seeking source for Author: Jim Hulberthulbe...@pb.com at P_Internet_Mail List-Post: emc-pstc@listserv.ieee.org Date:1/23/98 8:58 AM If memory serves me correctly, the old EMC regulations that existed in Germany long before the EMC Directive came into being (remember VDE 0871, VDE 0875, etc...?) included the provision that if a shielded power cord was needed to meet the emissions limits, then the cord had to be a non-detachable type. I'm aware of no similar restriction or prohibition of shielded power cords with regard to the EMC Directive. However, if such a cord is needed to meet the EMC Directive requirements, I would suggest including a statement to that effect in the operating instructions for the equipment. (BTW, a good source for shielded and filtered cordsets is EMC/EUPEN, tel: 908-919-1100.) Jim Hulbert Pitney Bowes __ Reply Separator _ Subject: RE: Shielded power cord, seeking source for Author: Rick Busche rbus...@es.com at SMTPGWY List-Post: emc-pstc@listserv.ieee.org Date:1/22/98 12:26 PM It is my understanding that shielded power cords are not allowed on products in European markets. As I recall, the rationale is that if a cord is replaced, there is no guarantee that it can, or will, be replaced with a shielded cord. -Original Message- From: Bob Blank [SMTP:bbl...@us.bnsmc.com] Sent: Thursday, January 22, 1998 12:24 PM To: emc-p...@ieee.org Subject:Shielded power cord, seeking source for Seeking source for shielded power cords to meet CE mark requirements. Prefer braided shield (80% tinned copper) instead of foil 18/3, CEE color coding, 10A, 125 V, PVC jacket, 9'10 long should have female connector PH-30 (angled IEC 320) molded on Should meet any other specs required for CE mark Any advice is greatly appreciated R. Blank Received: from curly.eng.octel.com (148.147.200.26) by m-internet.corp.octel.com with SMTP (IMA Internet Exchange 2.1 Enterprise) id 00017A46; Fri, 23 Jan 98 06:26:14 -0800 Received: from gw3.octel.com (gw3.octel.com [148.147.1.15]) by curly.eng.octel.com (8.6.12/8.6.12) with ESMTP id GAA01842; Fri, 23 Jan 1998 06:29:15 -0800 Received: (from daemon@localhost) by gw3.octel.com (8.6.10/8.6.12) id GAA29077; Fri, 23 Jan 1998 06:28:44 -0800 Received: from ruebert.ieee.org(199.172.136.3) by gw3.octel.com via smap (V1.3) id sma028982; Fri Jan 23 06:28:08 1998 Received: (from daemon@localhost) by ruebert.ieee.org (8.8.8/8.8.8) id JAA15081 for emc-pstc-list; Fri, 23 Jan 1998 09:01:43 -0500 (EST) Message-Id: 9801238855.aa885564...@smtppc.ct.pb.com X-Mailer: ccMail Link to SMTP R6.01.01 List-Post: emc-pstc@listserv.ieee.org Date: Fri, 23 Jan 98 08:58:04 -0500 From: Jim Hulberthulbe...@pb.com To: emc-p...@ieee.org Subject: Re[2]: Shielded power cord, seeking source for Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-emc-p...@majordomo.ieee.org Precedence: bulk Reply-To: Jim Hulberthulbe...@pb.com X-Resent-To: Multiple Recipients emc-p...@majordomo.ieee.org X-Listname: emc-pstc X-Info: Help requests to emc-pstc-requ...@majordomo.ieee.org X-Info: [Un]Subscribe requests to majord...@majordomo.ieee.org X-Moderator-Address: emc-pstc-appro...@majordomo.ieee.org
Re[2]: Shielded power cord, seeking source for
If memory serves me correctly, the old EMC regulations that existed in Germany long before the EMC Directive came into being (remember VDE 0871, VDE 0875, etc...?) included the provision that if a shielded power cord was needed to meet the emissions limits, then the cord had to be a non-detachable type. I'm aware of no similar restriction or prohibition of shielded power cords with regard to the EMC Directive. However, if such a cord is needed to meet the EMC Directive requirements, I would suggest including a statement to that effect in the operating instructions for the equipment. (BTW, a good source for shielded and filtered cordsets is EMC/EUPEN, tel: 908-919-1100.) Jim Hulbert Pitney Bowes __ Reply Separator _ Subject: RE: Shielded power cord, seeking source for Author: Rick Busche rbus...@es.com at SMTPGWY List-Post: emc-pstc@listserv.ieee.org Date:1/22/98 12:26 PM It is my understanding that shielded power cords are not allowed on products in European markets. As I recall, the rationale is that if a cord is replaced, there is no guarantee that it can, or will, be replaced with a shielded cord. -Original Message- From: Bob Blank [SMTP:bbl...@us.bnsmc.com] Sent: Thursday, January 22, 1998 12:24 PM To: emc-p...@ieee.org Subject:Shielded power cord, seeking source for Seeking source for shielded power cords to meet CE mark requirements. Prefer braided shield (80% tinned copper) instead of foil 18/3, CEE color coding, 10A, 125 V, PVC jacket, 9'10 long should have female connector PH-30 (angled IEC 320) molded on Should meet any other specs required for CE mark Any advice is greatly appreciated R. Blank
RE: Re[2]: Shielded power cord, seeking source for
Hello Bob,Rick, Tania and group, From EMC point of view, the use of a shielded mains cord is of no use. As Bob stated, the cord may be exchanged by the end-user (unless you create a Y or Z type of non-detachable mains cord), thereby annihilating your screening efforts. Any serious test house will therefore test your equipment with an unshielded mains cord. You are permitted however to prescribe the use of a screened cable to your customers. Much better however, and i believe even cheaper, is the appliance of an integrated mains filter/ cord socket. You won't need a screened power cord anymore. You may however require the screening for armoring purposes. (APEX directive) Ing. Gert Gremmen == CE-test, qualified testing, Consultancy, Compliance tests for EMC and Electrical Safety 15 Great EMC-design tips available ! Visit our site : http://www.cetest.nl The Dutch Electronics Directory http://www.cetest.nl/electronics.htm == -Oorspronkelijk bericht- Van:tania.gr...@octel.com [SMTP:tania.gr...@octel.com] Verzonden: donderdag 22 januari 1998 21:34 Aan:'Bob Blank'; emc-p...@ieee.org; Rick Busche Onderwerp: Re[2]: Shielded power cord, seeking source for Very interesting. I did not know this. Where is this stated in the standard, or elsewhere, and how exactly is this enforced? Tania Grant, Lucent Technologies, Octel Messaging Division tgr...@lucent.com __ Reply Separator _ Subject: RE: Shielded power cord, seeking source for Author: Rick Busche rbus...@es.com at P_Internet_Mail List-Post: emc-pstc@listserv.ieee.org Date:1/22/98 12:26 PM It is my understanding that shielded power cords are not allowed on products in European markets. As I recall, the rationale is that if a cord is replaced, there is no guarantee that it can, or will, be replaced with a shielded cord. -Original Message- From: Bob Blank [SMTP:bbl...@us.bnsmc.com] Sent: Thursday, January 22, 1998 12:24 PM To: emc-p...@ieee.org Subject:Shielded power cord, seeking source for Seeking source for shielded power cords to meet CE mark requirements. Prefer braided shield (80% tinned copper) instead of foil 18/3, CEE color coding, 10A, 125 V, PVC jacket, 9'10 long should have female connector PH-30 (angled IEC 320) molded on Should meet any other specs required for CE mark Any advice is greatly appreciated R. Blank
RE: Shielded power cord, seeking source for
Hi Rick. You wrote: It is my understanding that shielded power cords are not allowed on products in European markets. As I recall, the rationale is that if a cord is replaced, there is no guarantee that it can, or will, be replaced with a shielded cord. Not as far as I am aware, and I have been designing mains powered stuff since I was too young to know better... But then I'm not aware of any manufacturers of Moulded Screened Mains Cable assemblies, they are invariably home made. Screened mains cable is freely available on the reel (in the UK from people like RS Components for instance) and I have used it when I have had problems with radiated emissions or susceptibility on long mains cables. Usually when a filter demonstrates a particularly arkward resonance. Any component which is safety or EMC critical, and which may be changed by a subsequent user can be made a condition of compliance by a relatively simple statement in the instructions. i.e. under the general heading of 'Using as intended'. Use of the equipment without the particular cable is therefore 'Not as intended' and therefore shouldn't be expected to comply (and shouldn't be put into service). A thruppence worth perhaps. Chris Dupres Surrey, UK.
Re[2]: Shielded power cord, seeking source for
Very interesting. I did not know this. Where is this stated in the standard, or elsewhere, and how exactly is this enforced? Tania Grant, Lucent Technologies, Octel Messaging Division tgr...@lucent.com __ Reply Separator _ Subject: RE: Shielded power cord, seeking source for Author: Rick Busche rbus...@es.com at P_Internet_Mail List-Post: emc-pstc@listserv.ieee.org Date:1/22/98 12:26 PM It is my understanding that shielded power cords are not allowed on products in European markets. As I recall, the rationale is that if a cord is replaced, there is no guarantee that it can, or will, be replaced with a shielded cord. -Original Message- From: Bob Blank [SMTP:bbl...@us.bnsmc.com] Sent: Thursday, January 22, 1998 12:24 PM To: emc-p...@ieee.org Subject:Shielded power cord, seeking source for Seeking source for shielded power cords to meet CE mark requirements. Prefer braided shield (80% tinned copper) instead of foil 18/3, CEE color coding, 10A, 125 V, PVC jacket, 9'10 long should have female connector PH-30 (angled IEC 320) molded on Should meet any other specs required for CE mark Any advice is greatly appreciated R. BlankReceived: from curly.eng.octel.com (148.147.200.26) by m-internet.corp.octel.com with SMTP (IMA Internet Exchange 2.1 Enterprise) id 0001679E; Thu, 22 Jan 98 11:56:11 -0800 Received: from gw3.octel.com (gw3.octel.com [148.147.1.15]) by curly.eng.octel.com (8.6.12/8.6.12) with ESMTP id LAA19732; Thu, 22 Jan 1998 11:59:08 -0800 Received: (from daemon@localhost) by gw3.octel.com (8.6.10/8.6.12) id LAA27029; Thu, 22 Jan 1998 11:58:37 -0800 Received: from ruebert.ieee.org(199.172.136.3) by gw3.octel.com via smap (V1.3) id sma026515; Thu Jan 22 11:57:42 1998 Received: (from daemon@localhost) by ruebert.ieee.org (8.8.8/8.8.8) id OAA08266 for emc-pstc-list; Thu, 22 Jan 1998 14:26:21 -0500 (EST) Message-ID: 075e06e8b98ad111833500805fea67540c1...@torino.corp.es.com From: Rick Busche rbus...@es.com To: 'Bob Blank' bbl...@us.bnsmc.com, emc-p...@ieee.org Subject: RE: Shielded power cord, seeking source for List-Post: emc-pstc@listserv.ieee.org Date: Thu, 22 Jan 1998 12:26:12 -0700 X-Priority: 3 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.0.1458.49) Content-Type: text/plain Sender: owner-emc-p...@majordomo.ieee.org Precedence: bulk Reply-To: Rick Busche rbus...@es.com X-Resent-To: Multiple Recipients emc-p...@majordomo.ieee.org X-Listname: emc-pstc X-Info: Help requests to emc-pstc-requ...@majordomo.ieee.org X-Info: [Un]Subscribe requests to majord...@majordomo.ieee.org X-Moderator-Address: emc-pstc-appro...@majordomo.ieee.org
RE: Shielded power cord, seeking source for
It is my understanding that shielded power cords are not allowed on products in European markets. As I recall, the rationale is that if a cord is replaced, there is no guarantee that it can, or will, be replaced with a shielded cord. -Original Message- From: Bob Blank [SMTP:bbl...@us.bnsmc.com] Sent: Thursday, January 22, 1998 12:24 PM To: emc-p...@ieee.org Subject:Shielded power cord, seeking source for Seeking source for shielded power cords to meet CE mark requirements. Prefer braided shield (80% tinned copper) instead of foil 18/3, CEE color coding, 10A, 125 V, PVC jacket, 9'10 long should have female connector PH-30 (angled IEC 320) molded on Should meet any other specs required for CE mark Any advice is greatly appreciated R. Blank
Shielded power cord, seeking source for
Seeking source for shielded power cords to meet CE mark requirements. Prefer braided shield (80% tinned copper) instead of foil 18/3, CEE color coding, 10A, 125 V, PVC jacket, 9'10 long should have female connector PH-30 (angled IEC 320) molded on Should meet any other specs required for CE mark Any advice is greatly appreciated R. Blank
