Hi John: > The symbol you mentioned (IEC60417 No. 5020 - with the "rakes"), as well as > 5017, 5018, 5021, 5173 are used to identify (and/or) frame/chassis/ground. > The problem is that in our product, the terminal for return (0V) wires of > redundant DC POWER sources, has no connection to either of them. I am > afraid that due to similarities to the 5173, the upside-down letter T may > also be understood as indicating some kind of connection to > frame/chassis/ground. What symbol should be used? 0V? >From what you describe, I presume the terminal is floating with respect to the frame/chassis/ ground. In this sense, the terminals on your product are very similar to the terminals of a voltmeter. You have +dc and -dc, where the -dc is 0 volts with respect to ground, but not connected to ground. You might check IEC 61010 for ratings and markings for "floating" terminals. If I recall correctly, some value of voltage is inserted between the symbol and the terminal pair to indicate the maximum floating voltage. Good luck, and best regards, Rich This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
