Hi Peter & Rich, 1. I disagree with Rich in that this circuit cannot be an ELV interconnection circuit. ELV circuits are not permitted as such in 2.10.2 of UL1950 (IEC950 clones) There is a single exception to this in 2.10.3. But, since this is a coaxial cable connection intended for outdoor routing as Peter has stated, it is unlikely that this exception would apply. To accurately portray this circuit as SELV or TNV, TNV-1 and TNV-3 circuits are circuits with expected overvoltage conditions from Telecommunication Networks. As this cabling is expected to route outdoors (it is still not clear to what it connects to), are telecommunication networks involved? The definition of 1.2.8.8 (TNV circuit) could apply to "any" secondary circuit, and 1.2.14.7 (telecommunication network) excludes "SELV circuits connecting units of data processing equipment", but still leaves a lot of room for interpretation. Correct me if I'm wrong here, but if this circuit connects to a telecommunications network, then it is by definition a TNV circuit, classed 1, 2 or 3 as appropriate for the intended application. Otherwise, it is likely an SELV circuit, regardless of its routing. Peter, regarding your "TNV-1 exposed outdoors" statement, 1.2.8.9 states that overvoltages from Telecommunication Networks are possible. Outdoors? It doesn't state that. However, most overvoltage conditions and Telecommunication Networks exist outdoors and I suppose its commonly assumed (there's that word again) that overvoltages and outdoor applications closely coexist. And, if this circuit is a TNV-1 circuit it must comply with the overvoltage conditions found in 6.4.1 and 6.6 (UL1950). 2. Rich has given a reasonable answer here. But it was not stated as to what this coaxial cable connects to. Other connection conditions may exist depending on the application. 3. I also agree with Rich here in that SELV, by definition, poses no shock hazard as far as safety is concerned. As for the cable itself, the cable can only be Listed if its a completely assembled cable, otherwise, it may or may not be Recognizied. But, as there are many many applications out there, as well as many many coaxial cable styles, it would be impossible to give any kind of meaningful answer here to your question, Peter. 4. Rich's answer is a good one, however, the shield braid may not always be relied upon to provide a good ground return, depending on the application. Just some of my opinions to throw back into the fray. Best regards and holiday wishes, Ron Pickard [email protected]
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