John, Yes, I'm working late this morning!
Of course, in the event of a power cross between the telecommunications network and mains then any ICT equipment connected to that telecommunications network should remain safe due to the power-cross test required in UL 60950 (but not required by the present editions of IEC + EN 60950-1). Over and out. Richard Hughes In a message dated 09/12/2003 01:35:03 GMT Standard Time, [email protected] writes: Agreed. The issue was that of protection of low-voltage wiring from crossing to mains voltages within the home due to the effects of alteration or remodel of walls and such. I introduced telephone wiring as such wiring would be much the same as floating SELV in the event of a cross -- which John feels is a dangerous situation. I believe you agree because the impedance to ground of telephone wiring is too high, and because the current-carrying capacity of the telephone wiring is too low to reduce the voltage to ground. My comment was to suggest that such crosses within the walls and ceilings of homes in the USA are rare, and seem not as dangerous as John feels they are. He may have UK construction in mind rather than USA construction. Best regards, Rich
