Hello Roger: My copy of EN 60950 (I have just purchased) is the 2nd edition, incorporating amendments 1, 2, and 3 of IEC 950.
The overvoltage tests required are in section 5.3.2, table 18 of EN 60950 Amd. 3. (by the way, has anyone heard of amd. 4 of IEC 950 has been incorporated into EN 60950?). For a Telco transformer, in most cases, you will need a SUPPLEMENTARY INSULATION barrier, assuming you have sufficient isolation from your mains elsewhere. For Europe, assume a working voltage of 250VAC (in most cases). This is because of section 6.3.3, figure 17, where a SUPPLEMENTARY INSULATION barrier is required from earth to the network. (this requirement is to anticipate miswiring of the outlets, causing 250VAC to inadvertently appear at the network barrier: see EN 41003 section 4.4.2.) This gives you a dielectric test of 1.5kV. UL 1950 is the same. See also sections 6.4.2.1, 6.4.2.2, and 6.4.2.3. Hope this helped! All known disclaimers apply. Mel Pedersen Midcom, Inc. Homologations Engineer Phone: (605) 882-8535 E-MAIL: [email protected] Fax: (605) 886-6752 ---------- From: Roger Prenger[SMTP:[email protected]] Sent: Friday, January 31, 1997 3:16 PM To: [email protected]; [email protected] Subject: Telco Transformer Specifications Hey All, I have lost track. What are the required Voltage Specs for Telco transformers, in particular in Europe? Is this in the EN60950 3rd edition? Can anyone reference the exact section? Does the UL1950 have the same specifications? AdvaTHANKSnce, roger [email protected] "And the poets down there don't write nothing at all, they just stand back and let it all be." - "Jungle Land", Bruce Springsteen
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