I went out to look at this problem for a guy that has a barn located about 60' from his house and in his barn he has problems with his electrical system that was obviously done by every handy man in the area. Anyway the barn has a sub panel out there that has been only been breakered from inside the house with a 60A breaker which feeds the 3- #6s which don't seem to be in any conduits underground to the barn. So at the barn I have hot,hot, neutral no ground so the panel has been bonded at the sub panel location for grounding means (there is no ground rod out there).The problems are this I am getting 126v to the dirt in front of the panel. I'm getting 20v from conduits to the aluminum siding on the barn. I'm getting 107v on one leg and 149v on the other leg when I introduce a load to the sub panel meaning I turn on a light or something and when I turn it off the voltage goes back to normal 126v and 126v to ground.Heres the real weird part to me. Even though I have disconnected the HR that feeds an outlet box at the back of the barn and it is piped in 1/2" emt to a metal box with the hot and neutral in that pipe disconnected I'm getting a consistent sizzling of what sounds like a mini welder just arcing between the box and the emt connectors.That is confusing to me. Anyway my theory as to what is happening out there is that the feed that goes out to the barn is cut or damaged in some way that its causing these things to happen in (ex different potentials of electricity in the dirt all around the barn.) and I was wondering if anybody has any different theories.Any ideas would be appreciated.
Old Barn Wiring Problem Help needed
- Thread starter dave81
- Start date
- Status
Re: Old Barn Wiring Problem Help needed
Without a reference to ground being created with a grounding system, any measurements that you take to ground are mute.
What type of meter are you useing? A bench style multimeter will give you (some call them ghosts) readings of voltage that cannot carry current.
The earth itself is not a common point. Drive two rods down in the ground 100 feet apart, and you will find some difference in potential.
Wires could be broken underground causing measuring problems, but I would like to know more about the testing process before I jump to trying to advise you with an answer.
Without a reference to ground being created with a grounding system, any measurements that you take to ground are mute.
What type of meter are you useing? A bench style multimeter will give you (some call them ghosts) readings of voltage that cannot carry current.
The earth itself is not a common point. Drive two rods down in the ground 100 feet apart, and you will find some difference in potential.
Wires could be broken underground causing measuring problems, but I would like to know more about the testing process before I jump to trying to advise you with an answer.
Re: Old Barn Wiring Problem Help needed
Well I was using a Ideal multimeter that is digital with an amp probe on it.I'm not sure if thats what you mean by a bench style. I took one lead from this meter put it on the A phase in the sub panel in the barn and the other lead went into the dirt and I got 126v. So your saying its possible to get voltage thats unable to carry current, I believe it but I would be curious to see the theory behind that just for learning purposes because I have had that before where on a light fixtures lamp base I would get 120v with my Ideal tester in the screw shell but it was unable to light the bulb in that case it had a droppexd neutral was the problem. Any way on that topic is there a tester that will not show voltage of 120v unless you really have 120v not "ghost voltage".Let me know if I can supply more helpful info on the original posted question for you.
Well I was using a Ideal multimeter that is digital with an amp probe on it.I'm not sure if thats what you mean by a bench style. I took one lead from this meter put it on the A phase in the sub panel in the barn and the other lead went into the dirt and I got 126v. So your saying its possible to get voltage thats unable to carry current, I believe it but I would be curious to see the theory behind that just for learning purposes because I have had that before where on a light fixtures lamp base I would get 120v with my Ideal tester in the screw shell but it was unable to light the bulb in that case it had a droppexd neutral was the problem. Any way on that topic is there a tester that will not show voltage of 120v unless you really have 120v not "ghost voltage".Let me know if I can supply more helpful info on the original posted question for you.
Re: Old Barn Wiring Problem Help needed
i used to have a voltcon cant remember who made it... I use fluke t5 now, but it can fool you if you dont know what to look for.
I dont completely understand the theroy, but basicly the resistance of the meter is soo small that no current has to flow to make the meter read.
With the spring style meter, they draw a current in order to work.
i used to have a voltcon cant remember who made it... I use fluke t5 now, but it can fool you if you dont know what to look for.
I dont completely understand the theroy, but basicly the resistance of the meter is soo small that no current has to flow to make the meter read.
With the spring style meter, they draw a current in order to work.
Re: Old Barn Wiring Problem Help needed
Actually, it is the fact that the resistance of the meter is very high that makes it read ghost voltages. You are basically using the test leads as an antenna and the meter is reading the voltage picked up by the leads. Another way to look at this is the voltage divider formula.
You could place a resistor across the test leads at the meter to eliminate the ghost voltages. But that's probably not a good idea, since a real voltage could produce a shock hazzard if the resistor terminals are exposed. Also, you would have to use about 120 Kohms or more to keep it from dissipating more than 1/2 watt if placed across a real 240V source.
Easiest to get an analog meter like Jbwhite said. You want one with a low khoms/volt spec.
Steve
Actually, it is the fact that the resistance of the meter is very high that makes it read ghost voltages. You are basically using the test leads as an antenna and the meter is reading the voltage picked up by the leads. Another way to look at this is the voltage divider formula.
You could place a resistor across the test leads at the meter to eliminate the ghost voltages. But that's probably not a good idea, since a real voltage could produce a shock hazzard if the resistor terminals are exposed. Also, you would have to use about 120 Kohms or more to keep it from dissipating more than 1/2 watt if placed across a real 240V source.
Easiest to get an analog meter like Jbwhite said. You want one with a low khoms/volt spec.
Steve
Re: Old Barn Wiring Problem Help needed
The way I look at it for what you have described if you don't have a water line or other similar ground path back to the house then you can install that panel as you would a service entrance. Bond the neutral to the enclosure and drive a ground rod and ground the neutral, bonding the neutral to the enclosure with that green screw.
If you do have an established ground path from the house to the barn then you should have a grounding conductor with the L-L-N conductors and the panel in the barn is to be installed with an isolated neutral and separate ground bar.
What you don't want is any parallel current paths that would allow neutral current to retun to the service entrance through a water pipe of other conductive path between the house and barn.
The way I look at it for what you have described if you don't have a water line or other similar ground path back to the house then you can install that panel as you would a service entrance. Bond the neutral to the enclosure and drive a ground rod and ground the neutral, bonding the neutral to the enclosure with that green screw.
If you do have an established ground path from the house to the barn then you should have a grounding conductor with the L-L-N conductors and the panel in the barn is to be installed with an isolated neutral and separate ground bar.
What you don't want is any parallel current paths that would allow neutral current to retun to the service entrance through a water pipe of other conductive path between the house and barn.
- Status