Hi Brian, You likely will also see many products with no fuses, since if the product can be proven safe without fuses, then having 1 fuse or 2 only increases safety incrementally. For the reasons you give, 2 fuses are better than one. But one is better than none, and none might be good enough. Enough, yes?
Mike Harris/Teccom -----Original Message----- From: brian_kunde <[email protected]> To: emc-pstc <[email protected]> List-Post: [email protected] Date: Friday, October 06, 2000 7:26 AM Subject: Overcurrent Protection: One or Both Sides? > > >The issue of designing in Overcurrent Protection on one side or both sides of >the AC mains keeps coming up. We deal in Laboratory Equipment so the EN 61010-1 >is the standard we use. I'm not sure what EN60950 would say on the subject. > >The only area I have found that deals with this question is a NOTE in section >9.6 of EN61010-1 which says, "Overcurrent protection devices (e.g. fuses) should >preferably be fitted in all supply conductors." > >This seems "GRAY" to me and I get beat up on it all the time. I feel that >overcurrent protection should be on all current carrying conductors. With a >230V~ product you never know where in the world the product will be shipped, if >the AC Main has a grounded neutral, or if the receptacle is polarized. So, I >feel you never know for sure which line or if both lines will be "HOT" in >reference to Earth ground. > >If my thinking is correct, shouldn't ALL 230V~ products have overcurrent >protection on both sides of the line? I would think so, but I see products >everyday that only have ONE side of the line fused. My superiors feel that if >others can get away with it, why can't we. Why add the extra cost of double >pole breakers or double fuse holders if it is not necessary? > >Am I being too cautious or do I have a point? > >Thank you for your support and advice. > >Brian Kunde >LECO Corp. > > > >------------------------------------------- >This message is from the IEEE EMC Society Product Safety >Technical Committee emc-pstc discussion list. > >To cancel your subscription, send mail to: > [email protected] >with the single line: > unsubscribe emc-pstc > >For help, send mail to the list administrators: > Jim Bacher: [email protected] > Michael Garretson: [email protected] > >For policy questions, send mail to: > Richard Nute: [email protected] > > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
