Good info. What is an MSPD? With best wishes DESIGN IT IN! OOO – Own Opinions Only www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England
UK is a sovereignty, not a Zollverein-ty -----Original Message----- From: mickm [mailto:[email protected]] Sent: Tuesday, September 19, 2017 8:51 AM To: [email protected] Subject: [PSES] power strip details IEEE Std. C62.41.1 (2002 - reaffirmed 2008) contains a mountain of information. If you go to A.2.2.3 Voltages induced in cables adjacent to down-conductors, it covers the induced voltage in an open-circuit loop by a nearby lightning current. The induced voltage table gives values ranging from 50 V to 500 V. Do the same calculation for Ethernet cables and you end up with voltages in the kV region. The inclusion of a voltage limiter is not covered. The poor coupling between the source and victim means that the voltage limiter current is surprisingly small. My previous comments are comprehended with statements like "The resulting voltages induced in the loop by the fast-changing surge currents flowing in the grounding system can cause a large voltage difference between the power port and the telecommunications port". Hence paving the way for the use of MSPDs to reduce the inter-service voltage differences for equipment or equipment clusters. At the time of document creation, MSPDs where not widely used and in Annex D called "surge reference equalisers". To understand how the MSPD transfers the surge on one service to another you need to look at more modern documents like ITU-T recommendation K.98 (08/2014) Overvoltage protection guide for telecommunication equipment installed in customer premises. This Recommendation covers direct strikes to the incoming service feed, mains configuration types of TN-S, TN-C, TN-C-S, TT and IT together with effects of various earthing system lead lengths and earth electrode resistances. Time is running out for IEEE Std. C62.41.1, under new IEEE rules the life of a standard is 10 years. If nothing is done to revise C62.41.1 it with be withdrawn in 2018. Hopefully the IEEE PES Surge Protective Device Committee will take up this challenge and, as part of the revision rational, replace the 10/350 with the more realistic values from CIGRÉ Technical Bulletin (TB) 549 (2013) Lightning Parameters for Engineering Applications Regards, Mick Maytum Safety and Telecom Standards [email protected] https://ictsp-essays.info ------ Original Message ------ From: "Richard Nute" <[email protected]> To: [email protected] Sent: 18/09/2017 18:58:00 Subject: Re: [PSES] power strip details >Hi Ralph: > >Thanks for the reference. My comments are validated by ANSI C62.41.1 . > >Best regards, >Rich > > >-----Original Message----- >From: Ralph McDiarmid [mailto:[email protected]] >Sent: Monday, September 18, 2017 9:01 AM >To: [email protected] >Subject: Re: [PSES] power strip details > >Pardon me, the correct reference is ANSI C62.41.1 (finger trouble on >keyboard) > >Ralph McDiarmid >Product Compliance >Engineering >Solar Business >Schneider Electric > > >-----Original Message----- >From: Ralph McDiarmid >Sent: Monday, September 18, 2017 8:55 AM >To: [email protected] >Subject: RE: [PSES] power strip details > >While I agree that an SPD at the service entrance seems to be the way >to suppress surges resulting from direct/near/far lightning strokes, >ANSI C62.4.1 writes about switching transients on circuits which cause >oscillatory surges on the mains. SPD at service entrance might be less >effective for those. The ANSI standard seems a very good summary of >what is a complex topic. > >Ralph McDiarmid >Product Compliance >Engineering >Solar Business >Schneider Electric > > >From: Richard Nute [mailto:[email protected]] >Sent: Saturday, September 16, 2017 12:30 PM >To: [email protected] >Subject: Re: [PSES] power strip details > > >I believe the principal culprit is the extreme magnetic field that >surrounds the conductors when the surge protector operates rather than >the current in the PE conductor. This field can generate high voltages >in adjacent and nearby low-voltage conductors such as telephone and >data cables. Think air-core transformer. > >If the surge protector is at the service entrance, then the high >current is in the electricity supplier wires, and the coupling to >telephone, cable, and data cables is reduced due to the distance >between the wires. > >http://www.nemasurge.org/faqs/ > >Rich > > >From: mickm [mailto:[email protected]] >Sent: Saturday, September 16, 2017 1:40 AM >To: mailto:[email protected] >Subject: [PSES] power strip details > > >John, > It seems to me that TC 108 documents really devise surge protection >component tests rather that complete equipment tests and so miss some >hidden field gotchas. > >I with Richards point about surge protection, for me the concern is the >surge current being diverted into the PE system creating local PE surge >differential voltage rises. >Multi-service surge protective devices (MSPDs) - all in one surge >protection (mitigation actually) - can cause problems here by >transferring a surge on one service, say AC mains, to another service >e.g. telephone service, because that service feed offers a better path >for the diverted surge current than the PE connection. >Equipment connected to the protected output of the MSPD should survive >the surge, but equipment connected on the unprotected side may suffer >due to the unexpected diverted surge. Solution, put and MSPD on every >bit of equipment. Looks like a win-win situation for MSPD >manufacturers. > > >Regards, >Mick Maytum >Safety and Telecom >Standards >mailto:[email protected] >Ictsp-essays.info > >------ Original Message ------ >From: "John Woodgate" <mailto:[email protected]> >To: mailto:[email protected] >Sent: 16/09/2017 08:04:59 >Subject: Re: [PSES] power strip details > >I agree, but doesn't that also apply to surge-suppression built into >equipment? Should we stop requiring surge immunity testing on >equipment? > >With best wishes DESIGN IT IN! OOO – Own Opinions Only >http://www.jmwa.demon.co.uk/ J M Woodgate and Associates Rayleigh >England > >UK is a sovereignty, not a Zollverein-ty > > >- >---------------------------------------------------------------- >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 <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 >List rules: http://www.ieee-pses.org/listrules.html >For help, send mail to the list administrators: >Scott Douglas <mailto:[email protected]> Mike Cantwell ><mailto:[email protected]> For policy questions, send mail to: >Jim Bacher <mailto:[email protected]> >David Heald <mailto:[email protected]> > >______________________________________________________________________ >This email has been scanned by the Symantec Email Security.cloud >service. >______________________________________________________________________ >- >---------------------------------------------------------------- >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 <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 >List rules: http://www.ieee-pses.org/listrules.html >For help, send mail to the list administrators: >Scott Douglas <mailto:[email protected]> Mike Cantwell ><mailto:[email protected]> For policy questions, send mail to: >Jim Bacher <mailto:[email protected]> >David Heald <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]> > >- >---------------------------------------------------------------- >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]> - ---------------------------------------------------------------- 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]> - ---------------------------------------------------------------- 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]>
