I use pieces of ¾” plywood with dowels inserted through holes at the corners. Careful dimensioning of the dowels ensures correct distance between the top surface of the plywood and the table top, regardless of which side is up. An added benefit is that the portion of the dowel protruding above the plywood serves to keep the wires contained.
Regards, David Raynes Senior EMC Technologist National Technical Systems Inc. 5151 - 47th Street N.E. Calgary, Alberta Canada T3J 3R2 1-403-568-6605 x227 Fax: 1-403-568-6970 [email protected] <mailto:[email protected]> ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Grace Lin Sent: Monday, April 06, 2009 07:03 To: [email protected] Subject: Re: 10cm above GRP requirement for 61000-4-6 Bob, Thank you for sharing your auditing experience with us. Since you pointed out the thickness of the ESD insulating mat. I had mine measured. It is a little off the spec of 0.5mm. Does any member have suggestion of vendors for the 0.5mm (about 0.02 inches) insulation sheet in low quantity such as less than 10 (in the US is better)? Making a 10cm woodstand within 10% tolerance is much easier than the same tolerance for 0.5mm. In the US, a piece of 2"x4" lumber (the real dimension of 4" is about 3.5" or 8.89cm) plus a piece of 1/2" (1.27cm) thickness plywood will do the job. In order to obtain a smooth surface (used a router) from the 2"x4" lumber to glue to the plywood, I used 3/4" plywood to make up the dimension. The finish is three coatings of stain. The tolerance is less than 1mm (1%). Best regards, Grace On 4/4/09, Bob Richards <[email protected]> wrote: Well, the audit went well. The auditor had no problem with the 10cm spacers or the 80cm tables. However, he did have a bit of a problem with our ESD insulating mat, which he measured to be 0.45mm instead of the required 0.5mm. However, I mentioned the fact that the 61000-4-4 EFT standard is the only standard in the family that lists a tolerance, and it was +/- 10% for the 10cm spacing. So, he accepted the +/- 10%. I never figured my original question would spawn so much response. Thanks to everyone that participated. :-) Bob Richards, NCT. - 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.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 <[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.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 <[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.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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]>
