RE: Screened room move.
Hi Ian Charles, When we put in our chamber (Boston area, MA), we used dielectric breaks to all connections and mounting, isolated the power to the chamber and test equipment and then used a dedicated ground from ground rods. We were required to drive 3 rods, 6 ft down, we ended up driving a 4th because # 3 only went down 4 ft. Regards, Charlie Martin From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Grasso, Charles Sent: Friday, February 26, 2010 6:07 PM To: 'Ian White (UK)'; 'IEEE Forum (emc-p...@ieee.org)' Subject: RE: Screened room move. Hello Ian, A single ground rod should suffice – but it all depended on building codes! Best Regards Charles Grasso From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ian White (UK) Sent: Friday, February 26, 2010 2:24 AM To: IEEE Forum (emc-p...@ieee.org) Subject: Screened room move. We are due to move our EMC screened room within the next year to a new site. It is planned to be placed in a much larger building of steel and concrete construction. We have planned it to be placed close to an outside wall so we can pick up an outside earth which will be bonded in to the mass of the earth for safety reasons Could l hear your ideas on the best solution for earthing the screened room as l feel the present arrangement may be far from ideal. For example is it better to use a number of rod earth electrodes or some sort of steel mesh arrangement buried in the earth for a good RF performance. Thanks for your help. Regards Ian White (Project Engineer - Electronics) - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Re: Screened room move.
Hi Ian, Hans makes some great points. I installed a grid system under my entire building and all metal building structure is bonded to that around the periphery. The shield room is bonded all four corners to this mesh. Power for the chamber is supplied from a dedicated power supply, which itself is Transformer isolated from grid power. The goals were: 1) to make sure all metal stayed at the same potential in the event of a lightning strike for safety. 2) to make all RF potentials on and near the shield room effectively zero. All emissions instrument green wires use the room ground. I have seen a number of cases where noise on the building structure ingresses to the measurement through a ground connection. In thoese cases an inductor has helped. There are loads of compromises to be worked out. You may want to seek advice from a facilities guy, I suggest Wally Pilat of EMC Lab Services, but he's located in the USA. John Dearing of Teseq (UK) may know of someone local. Cheers, Derek Walton L F Research On 2/26/2010 12:44 PM, Hans Mellberg wrote: It depends if you want a single point ground or a distributed ground. For some applications there is a recommendation to use a “ufer” grounding scheme which is essentially a buried grounding grid. At our building, we were able to drill through our concrete floor and install grounding rods about 8feet or about 2.5m deep into earth. No need to place the shield room near the building’s side (unless you are above ground on a multi-story building) Our EMC semi-anechoic chambers were intentionally isolated from ground and only grounded at key locations per the manufacturer’s instructions. It would seem that a multiple distributed grounding scheme might have been better. Best Regards Hans T Mellberg Vice President of Engineering Bay Area Compliance Laboratories www.baclcorp.com 1274 Anvilwood Avenue Sunnyvale, CA 94089, USA (408)732 9162 x 3601 fax: (408) 732 9164 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ian White (UK) Sent: Friday, February 26, 2010 1:24 AM To: IEEE Forum (emc-p...@ieee.org) Subject: Screened room move. We are due to move our EMC screened room within the next year to a new site. It is planned to be placed in a much larger building of steel and concrete construction. We have planned it to be placed close to an outside wall so we can pick up an outside earth which will be bonded in to the mass of the earth for safety reasons Could l hear your ideas on the best solution for earthing the screened room as l feel the present arrangement may be far from ideal. For example is it better to use a number of rod earth electrodes or some sort of steel mesh arrangement buried in the earth for a good RF performance. Thanks for your help. Regards Ian White (Project Engineer - Electronics) - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com -
RE: Screened room move.
Hello Ian, A single ground rod should suffice – but it all depended on building codes! Best Regards Charles Grasso From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ian White (UK) Sent: Friday, February 26, 2010 2:24 AM To: IEEE Forum (emc-p...@ieee.org) Subject: Screened room move. We are due to move our EMC screened room within the next year to a new site. It is planned to be placed in a much larger building of steel and concrete construction. We have planned it to be placed close to an outside wall so we can pick up an outside earth which will be bonded in to the mass of the earth for safety reasons Could l hear your ideas on the best solution for earthing the screened room as l feel the present arrangement may be far from ideal. For example is it better to use a number of rod earth electrodes or some sort of steel mesh arrangement buried in the earth for a good RF performance. Thanks for your help. Regards Ian White (Project Engineer - Electronics) - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
Re: Screened room move.
I'm curious, how are cars, planes, and spacships bonded to earth for good RF performance? And they make okay faraday shields for certain frequencies. I think I'd tied it to the same green wire ground the AC mains brings in, otherwise there may be a potential difference show up between that green wire ground and the earth bond mentioned with all sorts of mischief showing up. The Telcom folks call it CBN? common bonding network. - Bill In the event of a national emergency, click on the following links to provide directions to your duly elected mis-representative. http://www.usa.gov/Contact/Elected.shtml or... https://writerep.house.gov/writerep/welcome.shtml http://www.senate.gov/general/contact_information/senators_cfm.cfm From: Ian White (UK) ian.wh...@uk.spiraxsarco.com To: IEEE Forum (emc-p...@ieee.org) emc-p...@ieee.org Sent: Fri, February 26, 2010 4:23:58 AM Subject: Screened room move. We are due to move our EMC screened room within the next year to a new site. It is planned to be placed in a much larger building of steel and concrete construction. We have planned it to be placed close to an outside wall so we can pick up an outside earth which will be bonded in to the mass of the earth for safety reasons Could l hear your ideas on the best solution for earthing the screened room as l feel the present arrangement may be far from ideal. For example is it better to use a number of rod earth electrodes or some sort of steel mesh arrangement buried in the earth for a good RF performance. Thanks for your help. Regards Ian White (Project Engineer - Electronics) - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
RE: Screened room move.
It depends if you want a single point ground or a distributed ground. For some applications there is a recommendation to use a “ufer” grounding scheme which is essentially a buried grounding grid. At our building, we were able to drill through our concrete floor and install grounding rods about 8feet or about 2.5m deep into earth. No need to place the shield room near the building’s side (unless you are above ground on a multi-story building) Our EMC semi-anechoic chambers were intentionally isolated from ground and only grounded at key locations per the manufacturer’s instructions. It would seem that a multiple distributed grounding scheme might have been better. Best Regards Hans T Mellberg Vice President of Engineering Bay Area Compliance Laboratories www.baclcorp.com 1274 Anvilwood Avenue Sunnyvale, CA 94089, USA (408)732 9162 x 3601 fax: (408) 732 9164 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ian White (UK) Sent: Friday, February 26, 2010 1:24 AM To: IEEE Forum (emc-p...@ieee.org) Subject: Screened room move. We are due to move our EMC screened room within the next year to a new site. It is planned to be placed in a much larger building of steel and concrete construction. We have planned it to be placed close to an outside wall so we can pick up an outside earth which will be bonded in to the mass of the earth for safety reasons Could l hear your ideas on the best solution for earthing the screened room as l feel the present arrangement may be far from ideal. For example is it better to use a number of rod earth electrodes or some sort of steel mesh arrangement buried in the earth for a good RF performance. Thanks for your help. Regards Ian White (Project Engineer - Electronics) - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com
