Joe, Under table 6 look at note 4. "Where the material group is not known, material group IIIb shall be assumed."
Best regards, Stephen C. Phillips At 03:01 PM 5/8/97 -0400, you wrote: > 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. > >
