Form: Reply Text: (25 lines follow) Currently, for Europe the BRI and PRI are considered TNV circuits operating within the limits of SELV. EN60950 and or EN41003 apply. Also ETS300046/047. The ETSs replace the requirements for line barriers from EN60950 with a 500v electrical strength test. However some approval authorities, notably the UK, consider the connection of other equipment which may be 'pluggable type A' (see 6.3.3 of 950 or 4.4.2 of 41003). This clause requires a supplementary barrier between the earthed SELV and TNV circuits. So in answer to your question it depends really on which safety lab you use. Some consider the Network as SELV, TUV for example, and only apply the test from the ETS. Others, UK based, consider it to be TNV within the limits of SELV. At the end of the day the safety requirements can be met by self declaration, so the choice of lab is yours. The safest route at the moment is to provide a supplementary insulation barrier.
For the future, the amendment 3 to IEC950 considers the TNV1 2 or 3 approach. We wait with baited breath for the PTTs to declare the TNV status of their networks. My opinion is that BRI willl be TNV1 and PRI will be SELV. Best regards Barry Singleton Approvals Specialist Securicor 3net Ltd. Tel: 01256 792174 Fax: 01256 840429 email: [email protected] Original text: (17 lines follow) >From [email protected], on 07/08/96 20:40: To: [email protected] ("'TREG'") Dear Tregers: I have some basic questions about digital (ISDN, HDSL, ADSL, T1, etc.) = lines concerning safety. I know that most countries in Europe consider = ISDN lines to be a TNV circuit, however, I have heard that Primary Rate = ISDN may be considered a SELV circuit by many. What are the others = considered? And how much does this vary from country to country? Thank you all very much. Mel Pedersen Midcom Inc. Homologations Engineer Phone: (605) 882-8535 e-mail: [email protected] fax: (605) 886-6752 Use Proportional Font: true Previous From: [email protected] Previous To: [email protected] ("'TREG'") Original to: [email protected] ("'TREG'")
