Dear All, A CO equipment with a 48 Vdc nominal supply has coxial cable connection to an outdoor transmitter. I have the following questions:
1. The coaxial cable output is conductively connected to the input. It carries the same voltage and an amperage of 1 A (limited to 3 A max). Assuming the input supply tolerance not to exceed 60 Vdc, does everyone agree that this is SELV? Some of you may argue that it is TNV-1 since it is exposed outdoors! Based on the 950 definition of TNV, to the best of my understanding, the circuit is not a telecommunication network voltage circuit. 2. 950 does not discuss protection of the equipment or user from lightning. It should be noted that the unit also has user accessible SELV interfaces. What type of tests or construction would you recommend for the coaxial interface? I believe the Impulse Tests in IEC 65 or in UL1492 should be highly recommended. 3. Are there any requirements for the outdoor coaxial cable? Should it be Listed cable for North America and if so, what type of Listed cable? Should it be Approved for Europe and if so, what type of Approved cable? Assuming the power output to the cable was limited in accordance to UL1950/EN 60 950 (ie output was limited to Class 2), should the cable still be Listed or Approved? 4. Assuming the input tolerance now to be max 72 Vdc (a secondary hazardous voltage circuit) which also makes the coaxial output connection 72 Vdc, does anyone see a problem with this type of circuit being transmitted through a coaxial cable to the outdoor transmitter? Thank you all. 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: [email protected] 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 [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
