Jim, Thank you! That took care of my concern.
Ken on 3/5/03 4:11 PM, Knighten, Jim L at jk100...@teradata-ncr.com wrote: > Ken, > > It is a potential shock hazard if the coax run is long and runs from > building to building (for instance) where the ground potentials may be > different in the different buildings. One can develop a large potential on > the shield of the cable, so that if you put yourself between the cable > shield and ground you may get a strong shock. That is the reason for > isolating the shield from more than one direct connection to ground. It is > a real issue. The result for EMI is, as you have noted, the creation of an > egregious EMI offender. I have used the chassis mounted BNC connectors with > built-in capacitors successfully. > > Jim > > > Jim Knighten, Ph.D. > Teradata, a Division of NCR http://www.ncr.com > 17095 Via Del Campo > San Diego, CA 92127 > USA > Tel: 858-485-2537 > Fax: 858-485-3788 > jim.knigh...@ncr.com > > -----Original Message----- > From: Ken Javor [mailto:ken.ja...@emccompliance.com] > Sent: Wednesday, March 05, 2003 12:58 PM > To: Knighten, Jim L; emc-p...@majordomo.ieee.org > Subject: Re: Ethernet coax connection > > Assume complete ignorance on my part. What is the safety concern? > > > on 3/5/03 3:50 PM, Knighten, Jim L at jk100...@teradata-ncr.com wrote: > >> Ken, >> >> Safety considerations are the reason for the spec requirement. You are >> allowed to ground the shield at one point. >> >> Try using a BNC coax connector with a built-in capacitor to ground. That >> gives you an AC connection to ground and is often quite effective. These >> are off-the-shelf parts. >> >> Jim >> >> >> Jim Knighten, Ph.D. >> Teradata, a Division of NCR http://www.ncr.com >> 17095 Via Del Campo >> San Diego, CA 92127 >> USA >> Tel: 858-485-2537 >> Fax: 858-485-3788 >> jim.knigh...@ncr.com >> >> -----Original Message----- >> From: Ken Javor [mailto:ken.ja...@emccompliance.com] >> Sent: Wednesday, March 05, 2003 12:38 PM >> To: emc-p...@majordomo.ieee.org >> Subject: Ethernet coax connection >> >> >> Question for list members: >> >> Background: I am troubleshooting a complex integration of military > hardware >> and COTS. One COTS piece of equipment has an RG-58 coaxial connection, > but >> the coax connector is an isolated feedthrough bnc. From a radiated >> emissions point-of-view, that is hurting us. One of the engineers here > said >> that is part of the spec - Ethernet shields are not supposed to be chassis >> grounded. >> >> Question: Can someone please explain the reason for that, and how this is >> usually handled to minimize radiated emissions? >> >> Thank you. >> >> Ken Javor >> EMC Compliance >> Huntsville, Alabama >> 256/650-5261 >> >> >> >> ------------------------------------------- >> 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: >> majord...@ieee.org >> with the single line: >> unsubscribe emc-pstc >> >> For help, send mail to the list administrators: >> Ron Pickard: emc-p...@hypercom.com >> Dave Heald: davehe...@attbi.com >> >> For policy questions, send mail to: >> Richard Nute: ri...@ieee.org >> Jim Bacher: j.bac...@ieee.org >> >> 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 >> -- Ken Javor EMC Compliance Huntsville, Alabama 256/650-5261 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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
