RE>IEC 950 / UL 1950 creepage and* 5/9/97
The values for Pollution Degree 1 are applicable to components and assemblies which are sealed so as to exclude dust and moisture (see clause 2.9.6 of CSA C22.2 No. 950-95) The values for Pollution Degree 2 are generally applicable to equipment covered by the scope of the CSA C22.2 No. 950-95 standard (IEC 950 based) The values for Pollution Degree 3 are applicable where a local internal environment within the equipment is subject to conductive pollution or to dry-conductive pollution which could become conductive due to expected condensation. Regards, Regan Arndt Safety Technologist NORTEL -------------------------------------- List-Post: [email protected] Date: 5/9/97 12:27 AM To: Regan Arndt From: [email protected] To any and all safety gurus, I am in the midst of trying to minimize the creepage and clearance requirements between TNV and SELV called out in IEC 950. My interpretation of tables 5 and 6 in sections 2.9.2. and 2.9.3 are that minimum clearance is 2.0mm and minimum creepage is 2.5mm. This is based on a global design using up to 250V mains, pollution degree 1 & 2 and Material Group IIIa + IIIb. The application is for Class I as well as Class II systems. I could not find a reference explaining the definition of the Material Groups and would appreciate any insight into a clause, etc. which I could reference to reduce these spacing requirements. Please also advise if you are in need of further details. Thx, Joe ********************************************************************** Joe Finlayson Manager, Compliance Engineering Microcom, Inc. ------------------ RFC822 Header Follows ------------------ Received: by nmisq2.miss.nt.com with SMTP;9 May 1997 00:25:54 -0400 Received: from bcarsde4.localhost (actually bcarsde4.ott.bnr.ca) by bcarsfbb.ott.bnr.ca; Thu, 8 May 1997 15:10:47 -0400 Received: from europe.std.com by bcarsde4.localhost; Thu, 8 May 1997 15:04:59 -0400 Received: by europe.std.com (8.7.6/BZS-8-1.0) id PAA13113; Thu, 8 May 1997 15:08:45 -0400 (EDT) Received: from world.std.com by europe.std.com (8.7.6/BZS-8-1.0) id PAA13100; Thu, 8 May 1997 15:08:40 -0400 (EDT) Received: from sw.microcom.com by world.std.com (5.65c/Spike-2.0) id AA02571; Thu, 8 May 1997 15:08:40 -0400 Received: from sw.microcom.com (root@localhost) by sw.microcom.com (8.7.5/8.7.3) with ESMTP id PAA24783 for <[email protected]>; Thu, 8 May 1997 15:09:38 -0400 (EDT) Received: from smtp.microcom.com ([199.99.215.11]) by sw.microcom.com (8.7.5/8.7.3) with SMTP id PAA24770 for <[email protected]>; Thu, 8 May 1997 15:09:37 -0400 (EDT) Received: from ccMail by smtp.microcom.com (IMA Internet Exchange 2.1 Enterprise) id 00016C26; Thu, 8 May 97 15:11:58 -0400 Mime-Version: 1.0 List-Post: [email protected] Date: Thu, 8 May 1997 15:01:07 -0400 Message-Id: <[email protected]> From: [email protected] (Joe Finlayson) Subject: IEC 950 / UL 1950 creepage and clearance requirements To: [email protected] Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Sender: [email protected] Precedence: list Reply-To: [email protected]
