Bill, You asked. > Does anyone know of any standards that provide guidance on where in-line fuses > must be located in relation to the power switch; 1) before the switch, that is > connected to the EMI filter or line, or 2) after the switch ( to the load side)? The > power switch and and fuses (LN) are both on the front panel of an electronic drawer > which primary power is 115VAC. We have researched both the IEC 950 standard > and the 1990 National Electrical Code book and found no clear guidance. Also I > would be interested in your thoughts on the rationale or justification for location.
I've seen AC connection schemes connected either way (fuse-switch or switch-fuse). The same goes for AC input modules with each one having many agency marks. I don't believe there's a technical "right way" here because having 2 essentially purely conductive devices connected in series doesn't really matter for the protection and performance of the circuit if these devices are physically located immediately adjacent to the AC entry point.. However, the significance would come into play if either were distantly removed from the entry point. Just my 2 cents worth. Regards, Ron Pickard [email protected]
