In a message dated 12/12/00, Peter Merguerian writes:
> Assume you have equipment with external power earthed (Class 1) power > supply with an earthed appliance inlet for conenction to the mains. The > power supply output is connected to a dc unit with a TNV-2 interface with > no separation to SELV. The dc unit has a earth stud for connection of an > external earthing conductor. All exemptions for basic insulation in Table > 19 is applied. > > My questions is: can the stud on the dc unit serve as my permanent > Hi Peter: Based on your description, my tentative answer would be yes. I'm not sure what the "DC unit" that you refer to is, but the crux of your question seems to be whether it is OK to have a separate grounding lug on the chassis of the equipment that mixes TNV-2 and SELV/ground, as opposed to requiring a hard wired ground associated with the AC power input. The use of the separate grounding lug is quite common on pluggable Type A equipment that needs to qualify for the exemptions under Table 19. I believe that the requirements for the grounding lug are contained in clause 2.5. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 http://www.randolph-telecom.com
