Axiom Home Page Forums General Discussion The Water Cooler Stupid electrical question

Our apartment's electrical system is pretty old, as in it still uses fuses, not circuit breakers.

For the first time today, I blew one of the fuses. We moved our microwave over to the same circuit as the fridge, which worked fine. What I didn't realize was that the other appliances (particularly the toaster oven) were on the same circuit as well. As soon as all 3 of those were on, piff... there goes the fuse.

After excavating the fuse box in the closet, I found that the fuse that blew was a 20 amp (screw in a la light bulb style). All I have for replacements is 25 amp fuses, so I used one of those. I'm guessing this is not the best plan, but hey, my fridge is full and it's Xmas. So is it safe to leave that fuse in? Is it possible that the 20 amp fuse was misused for that circuit? Is there any way to tell without calling in a pro?

From memory, in Ontario, you are allowed up to a 20amp fuse on a standard house circuit.

You are probably fine for a day or two, but I would consult with a local electrician.

You will alright for now to use the 25 amp fuse. Make sure you take as much as you can off that load until you can replace with the correct size (20 amp) fuse. To draw more than 20 amps on one circuit is quite a heavy load.

What I forgot to mention is the other circuits are 25 and 30 amp fuses.

Unless you know for sure, no guessing, that circuit can handle more than 20 amps it would not be a good idea to up the fuse rating. Unless you can have a pro come and test it to be safe I wouldn't recommend it.

OK, that's pretty much what I thought. Considering the microwave alone pulls 15 amps (according to my kill-a-watt), we may have to move it back to the other circuit.

That's what I would do Ken. It's better to be safe, for sure.

I say throw a 30 amper in there, get a big a$$ Rotel amp, and crank up those 80's on the same circuit. Oh my, I'm starting to sound like Wid with newbies.

In that old house what you need to be concerned with is the insulation on the wires. In my parents' old house in So Cal (with screw in fuses) the wiring had woven cloth insulation. The size of the wire (gauge) will dictate what size fuse you will max out at. If you go over that amperage you run the risk of overheating the wires and igniting the insulation on the wires - read: FIRE!!

I would be really surprised that a 120V circuit would go over 20 amp (12 ga wire). A 240V circuit could handle the 25 and 30 amp fuses you mentioned. Wid is right; get an electrician in there.

Scott

The fuse protects the conductors (keeps them from going up in smoke and burring your house down). Typically, home wiring is done with either 14 and 12 gauge. NEC tables only allow 20 amps for 12 gauge THNN. 14 gauge is good for 15 amp. I am only speculating, but I bet the other fuses you mention that are 25 / 30, are there because the circuits kept tripping and the last person just screwed a larger fuse in.