Power Surges

[Brewster Buffalo]

Not quite a computer problem but lost all electrical power in the house overnight. The power company engineer found blown 60amp and 30amp fuses. The latter is for the ground floor power circuit. All the other circuits are now working with a replaced 60amp fuse.


.He thought the cause might be one of the devices on that circuit e.g washing machine but I have tested all of these and they are fine. Nothing was operating overnight.
The other alternative might a fault in the ground floor wiring and an electrician is coming out to check it.


From my limited electrical knowledge I would have thought that , if a fault occurred in the ground floor wiring circuit , the 30amp fuse would go first and that would protect the 60amp fuse but is that wrong?

[EEngr]

Originally Posted by Brewster Buffalo

From my limited electrical knowledge I would have thought that , if a fault occurred in the ground floor wiring circuit , the 30amp fuse would go first and that would protect the 60amp fuse but is that wrong?

That's the theory. But if there is significant pre-load on the upstream (60 amp) fuse, it could go first (or both at the same time) due to a fault downstream of the 30 amp.

[netstruggler]

Originally Posted by EEngr

That's the theory. But if there is significant pre-load on the upstream (60 amp) fuse, it could go first (or both at the same time) due to a fault downstream of the 30 amp.

And assuming your 30A fuse holder has 30A fuse wire in it and not some other conducting material.

I’d consider replacing your fuse box with circuit breakers.

[Brewster Buffalo]

The power company engineer said that the bitumen sealant in the 60amp fuse box had melted so he thought that the 60 amp might be defective. I'm going to upgrade the fuse box.