Reply to: RE>Printed Circuit Board Layout Doug,
Part 68 makes no minimum clearance. UL 1950 3rd edition requires clearances much greater than what you have written. The path to your exact clearance is complicated, and there are exceptions for permanently earth grounded hosts and pluggable type B equipment. These exceptions are often used by rack mounted commercial gear. For most PCB's UL 1950 requires creepage and clearance of 2mm = 0.079" T-G, R-G, T-GSELV, R-GSELV. Michael Royer Senior Agency Compliance Engineer BABT Approvals Liaison Engineer N.E.T. (Network Equipment Technologies) 800 Saginaw Drive Redwood City, CA 94063 Voice: 415-780-4218 Fax: 415-780-5004 [email protected] -------------------------------------- List-Post: [email protected] Date: 9/27/96 8:42 AM To: Michael Royer From: [email protected] Hello Treggers, Our PCB house has given me a conundrum for T1 Ring/Tip/Ground clearances. They declare FCC 68 and UL-1950 3rd edition conflict with clearance recommendations. I'm not sure to what they refer - test voltages versus recommended clearances(?). I have always recommended min. of 0.02" between R-T and min. of 0.03" between R-G and T-G as I think may have been posted here before. Before I walk into a rat's nest, does someone know what they are talking about specific with each standard? ******************************************************* Doug McKean [email protected] ------------------------------------------------------- The comments and opinions stated herein are mine alone, and do not reflect those of my employer. ------------------------------------------------------- ******************************************************* ------------------ RFC822 Header Follows ------------------ Received: by Mac2.net.com with SMTP;27 Sep 1996 08:40:22 -0800 Received: from europe.std.com by unet.net.com (SMI-8.6/SMI-SVR4) id IAA26089; Fri, 27 Sep 1996 08:33:08 -0700 Received: by europe.std.com (8.7.5/BZS-8-1.0) id LAA25409; Fri, 27 Sep 1996 11:05:26 -0400 (EDT) X-Authentication-Warning: europe.std.com: daemon set sender to treg-approval using -f Received: from world.std.com by europe.std.com (8.7.5/BZS-8-1.0) id LAA25378; Fri, 27 Sep 1996 11:05:19 -0400 (EDT) Received: from smtp.paragon-networks.com by world.std.com (5.65c/Spike-2.0) id AA21541; Fri, 27 Sep 1996 11:00:17 -0400 Received: from Doug.paragon-networks.com (CAMELUS.paragon-networks.com [38.243.36.147]) by smtp.paragon-networks.com (Netscape Mail Server v2.0) with SMTP id AAA66 for <[email protected]>; Fri, 27 Sep 1996 11:02:50 -0400 Message-Id: <[email protected]> List-Post: [email protected] Date: Fri, 27 Sep 1996 11:01:16 -0400 From: [email protected] (Doug McKean) Organization: Paragon Networks X-Mailer: Mozilla 2.0 (Win95; I) Mime-Version: 1.0 To: [email protected] Subject: Printed Circuit Board Layout References: <[email protected]> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: [email protected] Precedence: bulk Reply-To: [email protected]
