Hello Peter: I have looked into this issue a bit, and have received different answers from different test labs. Clause 1.5.1 of UL 1950 and EN 60950 states "Where safety is involved, components shall comply either with the requirements of this standard or with the safety aspects of the relevant IEC component standard..."
For capacitors, the most stringent reading I have received is: For international use, the applicable IEC capacitor standard would be IEC 384-14. A Y2 capacitor would be the one to use here, as this is required to pass a 1500VAC Voltage Proof test. The creepage and clearance dictated by IEC 384-14 is 3.0mm (assuming a working voltage between 130V and 250V), and the minimum clearance is 2.5mm. This would exceed the UL 1950 and EN 60950 requirements for your case. Regarding resistors, I would refer to clause 6.3.3.1 and 6.4.2. 6.3.3.1 states that "...components bridging the insulation that are left in place during the electric strength testing shall not be damaged...". Also, I would use the logic dictated by clause 2.2.8.2 regarding resistors bridging DOUBLE INSULATION, and make sure that the external creepage and clearance distances between the terminals complies with the relevant creepage and clearance requirements. For Capacitors, I would recommend using an approved component. I don't think that there is a such thing for resistors however. Also, be aware of the ground to network isolation requirements in Norway, Sweden, and Finland. They require SUPPLEMENTARY INSULATION for a PRIMARY CIRCUIT between ground and TNV. This will increase the necessary creepage distance to 2.5mm, and clearance to 2.0mm. A Y2 cap should work here also. Check the TREG archives also, as there has been previous discussion on this issue. Just my opinion, take it for what it is worth. Mel Pedersen Midcom, Inc. Homologations Engineer Phone: (605) 882-8535 mpeder...@midcom-inc.com Fax: (605) 882-8633 ---------- From: Peter Merguerian[SMTP:pe...@itl.co.il] Sent: Thursday, January 07, 1999 2:56 PM To: t...@world.std.com; nebs@world.std.com; emc-p...@ieee.org Subject: (Fwd) resistors and capacitors between TNV-3 and SELV Dear Members, What about the use of unapproved resistors and capacitors bridging TNV-3 and SELV. Can they be accepted by testing to requirements of UL1950, Third Edition only (i.e. they must be rated min. 1500Vdc, pass dielectric test and have spacing between terminals min. 1.5 mm creepage and 1.0 mm clearance)? What about the use of such unapproved resitors and capacitors to meet EN 60 950? PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
