I noticed today that my well pump, which is 240V (USA) and is on a 20A dedicated breaker has dual 15A fuses:
In 8 years in this house it has never blown a fuse nor the breaker. So I assume 15A is adequate. (That said, since the 2 fuses are different perhaps at some point one or both has gone out).
The circuit runs:
[Main panel] — [pump fuse + switch box] — [pressure switch] — [pump]
This brings up some related thoughts:
Is there a good reason that the breaker and fuses would be for different current limits?
What's the point of having the fuses anyway? They seem redundant to the breaker.
Ditto in fact for this entire pump switch box.
Should I change the breaker to 15 A? If there ever is an overcurrent issue it would be more convenient if the breaker tripped rather than a fuse went out.
The fuses are in the same room as the breaker panel which is the main panel in the house.
I'm not necessarily going to change anything, really just trying to understand.
(I'm not sure what the white wire is for, I've never actually seen the pump and don't know if it requires a neutral. Or maybe the pressure switch is 120V using one leg?)