In reply to Art Michael's query re: Recognized Insulation Systems vs. just use of components rated that high individually.
I was told by UL several months ago that use of individually Recognized Components (wire, plastic, tape, etc) within their ratings is accepted when applying for Recognition of the Component they are used in (relays in my case) without being investigated as a Recognized Insulation System. The catch is, however, a Recognized Component containing a coil which was not qualified via a Recognized Insulation System is subject to acceptance or rejection IN THE END USE by determination of acceptability by the reviewer - while a coil based on an Insulation System must be accepted without question if used within it's Recognized rating. This all means the same Recognized Component could be rejected in some applications and accepted in others based on the whim of the reviewer if the component was qualified without use of an R/C Ins. Sys.. My question to UL applied to single coil relays. Personally, I wonder if you would have that latitude in multi-winding devices where isolation is critical. Might be worth asking UL specifically before using it. ***** Comments are my own and do not represent views of the corporation ******* Harold Leipold Senior Technical Specialist Siemens Electromechanical Components Inc. Tel. (812)386-2161 Fax. (812)386-2616 Internet [email protected] ---------- From: Art Michael To: emc-pstc Subject: UL 1950/CSA 22.2 No. 950 List-Post: [email protected] Date: Monday, September 30, 1996 11:25AM Hello all, A) What is this group's sense with respect to the need for a UL Recognized Insulation System (UL 1446) in a transformer operating in excess of Class A (65 Deg/C Rise) conditions, when the power supply wherein this transformer resides is being submitted for evaluation in accordance with NRTL marking considerations. NOTE: (Class B or better rated materials will be used for building the transformer -- They just will not be part of a UL Recognized Insulation System). B) My reading of the Harmonized UL/CSA standard, UL 1950 / CSA 22.2 No. 950, Third Edition, indicates that a component satisfying the relevant UL _or_ CSA component standard, can be used to satisfy the requirements of the harmonized standard. This rationale is derived from Paragraph 2.2.2 and the Annex P2 section addressing paragraph 2.2.2. Both UL 1446 and CSA 22.2 No. 0, General Requirements - CEC, Part 2 are referenced. To my knowledge, neither CSA (nor IEC 85) require the "systems" approach. C) Have I interpreted this correctly? ThanX, Art Michael A.E. Michael, Dir. of Engineering Product Safety Int'l 166 Congdon St. East, Middletown CT 06457-8061 U.S.A. Phone : (860) 344-1651 Fax : (860) 346-9066 Email : [email protected] Website: http://www.safetylink.com
