sfav8r
Senior Member
- Location
- San Francisco Bay Area
I just came from a call at an apartment bldg. where one of the units had lost power to all of the outlets.
It was pretty much a no-brainer because one of the fuses was blown and it was obvious that the circuit was overloaded by the numberous extension cords present.
The interesting part is that there were four fuses. I didn't think much of that at first, but then I started wondering why if there were four fuses, ONE blown fuse would take out all of the plugs. Pretty strange to have three light fuses and only one plug fuse.
What I discovered is that there is essentially two circuits, one for lights one for plugs. If EITHER of the bottom fuses is removed, all of the plugs stop operating. If EITHER of the top fuses is removed, all the lights lose power.
Why? I don't have a lot of experience with bldgs. of this vintage, but the only reason I can see for this is that the two fuese are in series to assure protection even in the event of a faulty fuse. This seems pretty unlikely and even if it was the case, why would there be a lug for each fuse instead of a common lug for the two fuses?
It was pretty much a no-brainer because one of the fuses was blown and it was obvious that the circuit was overloaded by the numberous extension cords present.
The interesting part is that there were four fuses. I didn't think much of that at first, but then I started wondering why if there were four fuses, ONE blown fuse would take out all of the plugs. Pretty strange to have three light fuses and only one plug fuse.
What I discovered is that there is essentially two circuits, one for lights one for plugs. If EITHER of the bottom fuses is removed, all of the plugs stop operating. If EITHER of the top fuses is removed, all the lights lose power.
Why? I don't have a lot of experience with bldgs. of this vintage, but the only reason I can see for this is that the two fuese are in series to assure protection even in the event of a faulty fuse. This seems pretty unlikely and even if it was the case, why would there be a lug for each fuse instead of a common lug for the two fuses?
