I have an electric water heater. It's probably nearing the end of its life
although it still seems to work fine.
There are two 30 amp fuses in a box near the heater and another in the
main panel upstairs.
Every six months or so, one of these fuses will blow.
They are all time delay fuses.
Fuses don't blow without a reason. But it seems to me if there were a
problem, the new fuse would blow. Yet if the past is any example, it won't
happen for another 6 months.
???
ds

--
=^..^=