We use blade fuses on all of our sites. We fuse the dc before feeding it into the GIGE-POE-APC.
On Mon, Mar 21, 2016 at 12:42 PM, Chuck McCown <[email protected]> wrote: > I am considering adding a fuse to a new version of my rack mount POE surge > suppressors. > > I know many of you like PTC resettable solid state fuses. I don’t recall > ever designing one in to anything. > Maybe I did on a phone device years ago, but that would have been to > satisfy a regulatory agency only. > > Studying up on them I learn that if you have a 1 amp “hold current” the > “always trip” current is 2 amps. > Not like a fuse, which is pretty well guaranteed to trip at any current > over the rating if you wait long enough. > > For a polyfuse, if your load is one amp, you have to have a design value > of greater than 1 amp hold current. > But then it takes double that to actually trip.. > > And then there is leakage current required to keep it in the tripped > condition. > It does not totally break the circuit. > > They are fairly inexpensive compared to glass fuses and fuse holders. > Could do auto blade fuses too. > > Not sure I have the room for anything but a polyfuse though. > > Anyone have strong opinions about this? >
