[screwball]

thought I'd look on the web for this and I found this site. Here goes...

my building was built in 1939 and has old cloth wire in it. My neighbors have all had their fuse boxes upgraded to circuit breakers, and since I recently fried a wire inside a conduit while hanging a fixture, I thought it's time to rewire the whole building. (I got an estimate of under $10k for the job)

but I just read on the WWW that since our fuses never blow, and we would get no additional power from the upgrade (got 100 amps already), that there's no real reason to change from fuses... in fact, it said that fuses are actually better protection than C breakers. So now I'm thinking to save a pile of dough and maybe only fix the kitchen wiring that I fried, and a few other assorted things that were on the estimate (if that electrician will still talk to me!), or possibly just have the rewiring done (to lose the cloth covered wire, ungrounded outlets, etc, but not change the panel-about half the cost.

I thought today, before I found this site, that I would call my insurance co, or possibly building and safety, and ask them what the deal is with changing the panel... if there's any advantage-- like lower insurance costs, or does it increase the value of my building, is it a lot safer, or what?

can you help me out here? Give me a clue?

thanks

[labman]

As far as I know, circuit breakers are more of a convenience over fuses than anything else. As long as you are careful to keep fuses matched to the loads and wiring, they provide the same protection. I assume when you fried the one wire, damage was limited because the fuse blew. With a circuit breaker, you can quickly restore power. With fuses, you must have, and be able to find the right fuse when one blows.

You really should take a look at the ungrounded outlets. If the building was wired up with conduit or armored cable, BX, the outlet boxes should be grounded already. In that case, you can safely use the 3 prong adapters as long as you actually screw the little grounding tab to the outlet cover. You can also safely replace the 2 prong outlets with 3 prong ones. Otherwise there is a real hazard from appliances designed for 3 wire cords.

[screwball]

Thanks for your informative response. Actually, the fuse didn't even blow, it was a "small fry" (heh)... well worn from rubbing the edge where it comes out of the "pipe" into the fixture/box, just a little "pop" and the lead just fell off. I tried tugging a little more wire out to attach more lead to, but there's just not enough. I could try to surgically solder a lead just inside the opening of the maybe 5/8" metal tube opening, but it's a pretty confined space to work in... screw it, call the electrician.

since i like to keep the building as original as possible, i'm now thinking to keep the fuses, and from what you're saying, it looks like i don't really need to change the wiring either, just the outlets if i feel like it. you didn't say anything about the cloth wrapped wire... could you say a few words about that? i've seen it falling apart in some buildings, but this one hasn't given me any trouble. i'll check into the grounded or not issue.

i know that when they change the panel, they now use a riser up to the roof (2 story), whereas in the past the line sloped down from the pole to maybe 10' above the ground. the codes have changed, so it's a big deal (and expensive) to "bring it up to code".

[labman]

I should have said something about the cloth covered wire. Nothing lasts forever. On the other hand, many things continue to function as long as you leave them alone. Even if the cloth would fall off the wire if you looked at it cross eyed, where it is in the conduit, you can't see it. Anywhere the wire is exposed and in bad shape, the safest thing would be to replace it. As for what is out of sight, mostly you can leave it alone. Make sure the conduit is all securely anchored and none of the joints are broken. I am guessing your building is old enough that the conduit is the heavy wall threaded type not near as subject to coming apart. I think the thin wall held together with set screws is much more modern than the cloth covered wire. Conduit and wiring buried in the wall is not likely to have problems. As long as the conduit is all grounded, and you are attentive to having reasonable sized fuses, if there is a problem, the fuses should protect you from damage or injury. I think the older wiring was at least 12 gauge, and good for 20 amps. You can check the ground on the conduit by checking for full voltage between the hot wire and the conduit with either a test light or meter.

Any time you are forced to disturb the old wiring, you should plan for having to replace some of it.