Electrical Problem in old garage/shed

[Zeugitai]

We live in rural Iowa. We have an old garage (built 1924) that we use as a shed for equipment and as a winter home for our chickens. Our power comes into our two acres to a transformer on top of one pole, and then another pole has our meter and a box at the top from which two lines run, one to the house and one to the old garage. the line to the old garage has a 30A fuse wired into it as it comes through the wall. We have had a couple bulbs on this line for some heat for the chickens. The line went dead. The fuse is OK. I put a tester on it for ACV and am getting readings of 30V. The house electric is fine. Can anyone help me get oriented? We can't afford to hire an electrician. thanks.

 

[murphy1244]

Put your probes on each side of the fuse while still in its slot, If you read voltage your fuse is blown.

 

[Zeugitai]

Thanks. I'll replace it and see what happens. I am getting the 30V reading on the line with the fuse in place.

 

[murphy1244]

Your very welcome.
Should be 120 volts your reading.
Murph

 

[Zeugitai]

That's what threw me off, Murph. I don't know much but some basics, but I expected to see zero voltage and instead I am seeing 30v? Couldn't figure that out. Thanks again.

 

[CobyRupert]

Hmm, one would expect to see either 120V or 0 volts. Sometimes when one sees these odd results it means a bad neutral-ground. Is this just a 120V volt (single phase) service with just one fuse or are there 2 fuses? Where did you test across to get the 30V? Across the fuse? From the load or line side of the fuse to a grounded neutral conductor? Or from the load or line side to a grounded object?

 

[KennyG]

Low voltage in a branch line is often a poor connection, often in the common side (white wire). I had a problem with 220 service to a building which confused me originally because my 220 volt equipment ran fine but my 120 tools had no power. A damaged common wire left me with only 50 or 60 volts on the 120 circuits.

 

[Zeugitai]

Yes, it's a single phase service with one fuse. Couldn't be more primitive. Definitely jerry-rigged by someone in the past. But it's been working fine for the five years we've been here. I put the tester across the fuse itself as it comes through the wall from the pole and also put it across the switch on the wall farther down the line. I guess that's the load side. I get 30v. the wires are ancient. no color differences. We likely overloaded this line with several bulbs on extension cords running from the one and only outlet on this line.

 

[CobyRupert]

Yes, having 50 or 60 volts on one normally 120V leg would be typical on a 220 volt service when the neutral is broken, but then of course the voltage in the other (normally 120v) leg would be 160 or 170 volts. That's why if the service to the OP's garage is just a 120v service, getting 30 volts is odd, but still could be caused by a loose connection rather than a complete open break.

 

[Mace Canute]

Yes, it's a single phase service with one fuse. Couldn't be more primitive. Definitely jerry-rigged by someone in the past. But it's been working fine for the five years we've been here. I put the tester across the fuse itself as it comes through the wall from the pole and also put it across the switch on the wall farther down the line. I guess that's the load side. I get 30v. the wires are ancient. no color differences. We likely overloaded this line with several bulbs on extension cords running from the one and only outlet on this line.

Try testing the voltage before the fuse. You have to put one lead on the hot leg and the other lead on the neutral. Let us know what you have.

 

[CobyRupert]

"I put the tester across the fuse itself as it comes through the wall from the pole and also put it across the switch on the wall farther down the line. I guess that's the load side. I get 30v. "

Now I'm confused. Are you saying you put one probe of the tester on one end of the fuse, and the other probe of the tester on the other end of the fuse and got 30 volts?

When you say "across the switch" and got 30V, what did you put the probes across?

 

[jefwyn]

I'm sure you are not doing this, but just in case, I'll put this out there. I have seen guys, and might have done it myself, read the voltage, not noticing that it was milivolts.

 

[Pete Judd]

Jefwyn, I also have a high end auto ranging meter and you can't watch that decimal point. Bit me a couple of times.

 

[uglyboywith11fingers]

I'd be suspect of a 30 volt reading across the fuse...
if the fuse is good, there should be essentially zero voltage drop across it, current flow or not.
if the fuse is blown, there should be 120 volts across it if the rest of the circuit is complete, ie. switch is on, bulb is good. if circuit is not complete, should read close to zero across the fuse.

you need to read the voltage between the 2 wires that come into the building.

 

[KennyG]

I'd be suspect of a 30 volt reading across the fuse...
if the fuse is good, there should be essentially zero voltage drop across it, current flow or not.
if the fuse is blown, there should be 120 volts across it if the rest of the circuit is complete, ie. switch is on, bulb is good. if circuit is not complete, should read close to zero across the fuse.

you need to read the voltage between the 2 wires that come into the building.

I thought he meant across the lines AT the fuse. We're all guessing at this point aren't we. :laughing:

 

[grsthegreat]

Need to remove fuse and run a ohm test on the fuse.

Or do as Mace suggests and test real voltage between neutral and line side of fuse. (thats the incoming power before the fuse)

In the past i have gotten fake ---low--- readings like 30 volt or 60 volt on systems that had lost the neutral, but got a partial return voltage thru the ground . This voltage disappeared when i removed all light bulbs from their sockets, and unplugged all outlets. After the neutrals were repaired..all was well again.

Also you need to check voltage where power originates at main panel or house.

 

[radioman]

first of all -- you have what its called a voltage drop. either using too much or too far. you need to pull the fuse and measure the voltage at line in connection at box in garage. 120? good. you know line from garage to second pole is likely good. this likely means you have a burnt line or plug or short in extension or fuse connection issues. do you see any deformed or wrinkled appearance of metal fuse connectors? no? with fuse pulled - check ohms resistance of line going to rest of garage. is it open or closed? closed? I'd start investigating the lines in garage and unplug everything in sockets and pulling bulbs and recheck. still closed? then you got bigger issues. its time for a rewire IMHO. I bet once you replace the wiring to everything in the garage- you will find the culprit and you will prevent any future fires from other wiring.
One other thing to check - do you have any junction boxes in your garage? with fuse pulled - I'd start checking and retighten the junction connectors or find a way to eliminate it. A loose wirenut can cause same issue you are having.

 

[Gunny]

Along the line of checking any junction boxes for loose connectors - are there any splices in the lines between the house and the shed? A lot of the old splices amounted to twisting the wires together and taping over them. Very easy to have corrosion build up in them and weaken he conductivity.

 

[Mace Canute]

Along the line of checking any junction boxes for loose connectors - are there any splices in the lines between the house and the shed? A lot of the old splices amounted to twisting the wires together and taping over them. Very easy to have corrosion build up in them and weaken he conductivity.

X 2. :thumbsup:

I wish the OP would come back and give us some more information on what he found.