I haven't read this whole thread yet, but I try to avoid fuses in my products. As pointed out they are big. They also nuisance trip. When the line current is low enough, I've designed in PTC thermistors for overcurrent protection. BC Components has a series of them rated at 260VAC. I believe they are a UL recognized component. Our test lab has listed our products as compliant with UL508 when we use these parts. The other pain with line voltage on a circuit board is creepage distances. It's real hard to run any traces when you need to leave so much space between them! Harold > On 12/18/05, William Chops Westfield wrote: >> >> >> fuses are cheap and relatively small >> >> Fuses are HUGE, especially if you want to use common replaceable types. >> get depressed every time I try to "harden" one of my PCB designs by >> adding fuses... > > Fuses are really HUGE but I have to put it in for UL approval. ;-( > Of couse big and samll are always relative to the board size. ;-) > I was using three fuses for one EEx ia product (Intrinsic Safety product > used in explosive environment) and the brand of the fuses to choose for > Ex use was really limited for PTB approval. But it is of course necessary > to put them in so that extra reliability/safety can be achieved. > > Regards, > Xiaofan > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- FCC Rules Updated Daily at http://www.hallikainen.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist