Any electricians in the house? Maybe just an electro-nerd could help....

[thefed]

Quick question, i'll make it as simple as i can...

i have a rental home with fuses. Theres a main box, with 4 fuses (the small round type). Above those 4, are two "MAIN" fuse things....when you pull out the MAIN fuse thing, there's two 60a time delay fuses in it (they look like huge old-car fuses...cylinder in shape and maybe 3 inches long). Remember, there's 2 main fuse things


So my tenant calls, says 1/2 the house is out of electricity (was running multiple space heaters)...she changed all small fuses and no go. so i tell her to check the main fuse things...none look blown. So i have her physically swap the 2 big car-like fuses from MAIN FUSE THINGY 1 with the big car-like fuses in MAIN FUSE THINGY 2. Nothing...no power anywhere. So she switches them back, and BAM...all the lights are on everywhere.

WTF??anuy ideas?

[UncleHoney]

Sounds like a bad connection in the fuse box or just dirty terminals on the fuse block.

Better have a look at it to make sure nothing in the fuse box is getting too hot. Also make sure all the fuses are the correct amperage for the circuits they protect. Most old systems only used 15 amp fuses on the branch circuits. The rule is 15 amp fuses with 14 gage wire and 20 amp fuses with 12 gage wire.

Maybe time to upgrade to a breaker panel.

UH

[wallygator69]

Hi,

BSEE have experience with 1940's camp with similar fuses.

Doesn't make a lot of sense. A true Electrician is going to tell me I am wrong with the technical Jargon but..

You typically have about 230VAC on two phases coming into the box. Each phase will drive half of the house at 115VAC. Ones I have seen have one MAIN Fuse for each phase. You appear to have two per phase. So if you told me 1/4 of the house was out I'd assume one of the fuses was gone but half the house makes no sense.

It's working now but it seems like a simple upgrade. I'd spend the $500-$1000 and get circuit breaker panel put in....

Tenants replacing master fuses at your instruction is a lawsuit waiting to happen...

Good luck.

W

[wallygator69]

Hi,

I think I got it....(do my best work while sleeping or trying to.... Had to get up or I'd never get to sleep)...

The fact that you only have 4 small round fuses which can't be rated for more than 20 amps each or a total of 80 amps but have 4 main fuses rated at 60 amps each implies that one of the big fuses in each MAIN Thingy are not being used.

One of the big fuses is blown but when your tenant put them back she put the bad one into the slot that isn't doing anything.

You can easily check this yourself by swapping each of the Main fuses back and forth within the same Main Thingy....Or take the cover off the box and see if wires are coming off of both of the fuses. Some folks/Electricians will "store" a good fuse in an unused spot because if your in there you don't have to look arounfd for a good one..... If this is the case I probably wouldn't bother upgrading the box but....

Just for SHITES AND GIGGLES.

For a 60 amp slow blow to go it could be age related. If it's 30 years old they do degrade a bit but still kind of weird that it would blow before the 20 amp small fuses would go. I would double check and be sure that 3 of the small round fuse are not coming from one main thingy and that only one is connected to the other. Each Main Thingy should probably be driving two 20 amp round fuses each.

Good Luck and let me know what you find.

W

[Telly]

Quote:

Originally Posted by thefed Quick question, i'll make it as simple as i can... i have a rental home with fuses. Theres a main box, with 4 fuses (the small round type). Above those 4, are two "MAIN" fuse things....when you pull out the MAIN fuse thing, there's two 60a time delay fuses in it (they look like huge old-car fuses...cylinder in shape and maybe 3 inches long). Remember, there's 2 main fuse things So my tenant calls, says 1/2 the house is out of electricity (was running multiple space heaters)...she changed all small fuses and no go. so i tell her to check the main fuse things...none look blown. So i have her physically swap the 2 big car-like fuses from MAIN FUSE THINGY 1 with the big car-like fuses in MAIN FUSE THINGY 2. Nothing...no power anywhere. So she switches them back, and BAM...all the lights are on everywhere. WTF??anuy ideas?

What you describe is a typical (and old!) fuse box. One Main fuse pull-out has two higher-amp fuses, each one of those fuses feeds two of the 120 volt branch circuit screw-in fuses.
The second Main pull-out with higher-amperage fuses is a parallel circuit used to power an electric oven, or electric clothes drier, etc., a high-amperage 240 volt load.

On many of these boxes, the Main can be pulled out, and if rotated top to bottom, can be plugged back in... but will not make contact. It is a storage position that covers the A and B Line Feeds, while disconnecting the subtending circuits. So if someone "swapped" them, and it didn't "fix" it, then swapped them back, and it now worked, I would suspect that one of them may have been inserted upside down in the first step of the swap attempt. So one of them may have a blown main fuse after all. If this is the case, then if there is indeed a electric oven/Drier on the other Main pullout, it won't be working now.

If the box is in good shape still, it should take quite a bit of effort to pull out a Main pullout, and a solid push to reseat it fully. If it goes easy, the prongs and or socket are weakened and it will be a hot spot and trouble in high load conditions.

[thefed]

wow, tanks for the insight...ypu guys are great....and it makes sense


what makes more sense is me paying ym electrician 700 bucks to come out and put in a new box for me

One thing i neglected to mention is this:theres 2 more panels in the house as well! one in an addition added in the 80s (4 small 20 a fuses,no main) and another in the garage added @ the same time (same deal, 4 20a fuses,no main). the garage went out with the old part of the house

come to think of it, she said "half the house was out" im pretty sure the side that stayed on was the new addition from the 80's

does this change anyone's assessment?

either way, it's getting swapped...but i hate to have to pay for THREE panel changes...though the two smaller ones should be cheaper

[samclem]

Telly,
Wow! "Alex, I'll take 1940's home electric troubleshooting for 1000." Great!

The fed,
USAA wouldn't insure my present home (built in 1959) until I swapped the old fuse box for a modern panel with circuit breakers. I don't know if this is a common practice, but you might want to be sure your properties are covered despite the older panel. I think the standard fuses provide adequate protection, provided folks replace the fuses with the proper sizes when they blow. I'd be worried about that in a rental property.