fuses in series
- Thread starter robeward
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ron
Senior Member
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- New York, 40.7514,-73.9925
If they are in series, they both "see" the same current. If the curves overlap at that current, you melt both (without considering manufacturers tollerances).
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
If the curves overlap at that current, I would expect the time constant for one fuse to be different from that of the other. In that case one might melt open first although the other might suffer some sag and change in properties if the current was interrupted before it actually blew.
For identical fuses it is likely that both would melt down, although only one of them might show the deposition of metal on the shell resulting from the arc when the fuse opens.
For a non-glass cartridge fuse, you would likely not be able to see any internal changes to the fuse short of blowing.
the reason for asking is our work involves a lot of stepping up and down of voltages, fused sectionalizers plus a fused disconnect at each load. coordination is always an issue especially when MV fuses are used. Their curves are not as tidy as the LV ones.
Is choosing similar fuses in series situations a bad idea? I understand it potentially causes two fuses to blow instead of one therefore increasing cost but i wasn't sure if partial melts were a real possibility in which the service could be left in a less predictable state without anyway of knowing.
Is choosing similar fuses in series situations a bad idea? I understand it potentially causes two fuses to blow instead of one therefore increasing cost but i wasn't sure if partial melts were a real possibility in which the service could be left in a less predictable state without anyway of knowing.
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