Home>Discussions>ELECTRICAL & LIGHTING>Received a shock froum the ground (dirt) outside my house
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Jasondart
Received a shock froum the ground (dirt) outside my house

I found this site because I "Asked This Old House" I love it and will become a frequent visitor.

The other day it was warm (34 F) and the ice/snow was melting. I reached down to clean out some leaves in my down spout on my aluminum gutter and I received a shock. I quickly grabbed my meter and with the black probe stuck in between the slabs of concrete, I touched the red probe to the metal on the gutter and got 50 volts.

I then turned off the main breaker at the electrical panel and tested again no voltage. I started to turn on breaker by breaker and found the exact break that was causing the issue. That breaker is for 5 ceiling lights located on the 1st floor in the same corner as the gutter down spout.

My next step was to remove the screws holding the brackets in place for the gutter downspout. I thought maybe one is screwed into a wire. That did not fix the problem. At that point I tested again, with black probe stuck in the ground again I touched the ladder, 50 volts, then I touched a metal hinge on my wooden fence, 30 volts. The actual ground is electrified.

The worst part is if I turn off all breakers on the panel except the one causing the problem and turn off all lights on that breaker (I don't believe any outlets are on that breaker) I see the electric meter spin. I am using power due to the problem. Two days after the problem it got below freezing and the ground dried up. I could not get a reading using the same techniques. It seems to only happen when it rains or is wet.

The house is stucco on the outside and plaster lath on the inside. The circuit panel is newer and all the wiring in the basement is newer, but most of the wiring in the house is old. the problem does not exist with any other downspout. In the problem area there is a detached garage (on a different breaker) with in 4 feet and the main power line and ground with in 3 feet. Can anyone help?

canuk
Re: Received a shock froum the ground (dirt) outside my house

Sounds like you can rule out the feed from the utility as being the source for the stray current.

Are there any receptacles tied into this circuit you identified as being the source?
Is the water service located near this point?

It almost sounds like a that a ground wire maybe tied into a neutral and grounded to a copper water line.

Just a guess.

Jasondart
Re: Received a shock froum the ground (dirt) outside my house
canuk wrote:

Sounds like you can rule out the feed from the utility as being the source for the stray current.

Are there any receptacles tied into this circuit you identified as being the source?
Is the water service located near this point?

It almost sounds like a that a ground wire maybe tied into a neutral and grounded to a copper water line.

Just a guess.

I do not believe there are any receptacles tied to this circuit. I tested a few I thought might be (with the circuit breaker off) and they were not part of the same circuit.

Water service is on the exact opposite side of the house.

I have some more testing to do, just to rule out a few things.

Blue RidgeParkway
Re: Received a shock froum the ground (dirt) outside my house

Jason,
Do you have a door bell?

Jasondart
Re: Received a shock froum the ground (dirt) outside my house
Blue RidgeParkway wrote:

Jason,
Do you have a door bell?

Yes, but it is plugged into an electrical outlet on a different circuit, but I believe there is remnants of an older one in the basement. Why?

Blue RidgeParkway
Re: Received a shock froum the ground (dirt) outside my house

Oh not much, just remembering some unpleasant shocks received years ago. Prior home had an old abandoned but not fully decommissioned doorbell system when tracked it down and found still connected and hidden, abandonded burried wires behind the outside wall, electrifying the metal lath, CATV coax with bad trim job on the shielding mounted and poorly grounded nearby, water was the added ingredient making a contact shock possible - it was an unpleasant and frustrating "hunt" to find the culprit.

What are you using to "detect" this voltage? A solid state voltimeter/digital multimeter or an analog voltmeter?

I'm asking to determine if you're meter is displaying 50 volts but is picking up microamps of what is sometimes refered to as "phantom voltage" with a digital multimeter or a voltage reading of consequence detected with a good old fashioned analog voltmeter.

If you're using a digital voltmeter, hopefully, you understand why that kind of meter's extremely high input impedance combined with capacitive coupling of ac signals between powered and unpowered conductors can let the meter display voltage readings which are accurate but exist only because there's just
microamps of current flow.

If you don't understand those principles, learn about them or you'll be following false trails which will lead you to incorrect conclusions.

If you're using an analog voltmeter then I'd be hunting for a source, if you're not using an analog voltmeter I'd get my hands on one and check for voltage before I started a wild goose chase without one.

docbob
Re: Received a shock froum the ground (dirt) outside my house

Just some thoughts.

1. It sounds like the whatever contact is being made with an energized line is made by water. When things are wet, you read the voltage, when they are dry, you don't. By the way, when it got down below freezing, not only did the ground dry up, but drips or seepage of water under flashing, between downspouts and the exterior walls, etc. dry up too.

I don't want send you on a wild goose chase, but you might look for signs that water is seeping or driping through the roof, out of the gutters, or down the wall and into exterior outlets, fixtures, or even the meter box.

Some time ago, I had a old fuse box with two 60A fuses feeding a mobile home. A small spot on the back of the box was rusted and when it rained, water would run down the riser and wall, over the outside of the fuse box, and past the rusted part of the box to the ground. The only way we found it was that eventually, the situation got so bad that water began to collect inside the fuse box and blew the fuse. Once we replaced/upgraded the box with a new breaker box, not only was our problem resolved, but our electric usage was cut in half.

Before going too far, though, make sure your meter is reading properly. Stick the probes into an outlet to make sure it is reading what you expect (but only if its made for that, of course). Your voltage reading on the ladder - particularly if it is resting on the ground and leaning against the house, is really strange.

G'luck

Jasondart
Re: Received a shock froum the ground (dirt) outside my house

Thank you for the ideas. It dawned on me that maybe this spring I will try to just soak the ground with a hose to see if it is that. If so, I can narrow it down that it is not something seeping behind the flashing or something like that.

I have been told that it could be just a nail or screw coming in contact with a wire. I really want to do some more searching and I think I will first check all the light switches and lights where they mount to the ceiling. I won't know if I fixed anything until it is wet out again.

I do have a few questions that I know you all can help me with.

#1. How do I test an outlet for power? How do I test a mail head to see if it is touching a wire? I think I need to ground my meter, what would be the best way to do this?

#2. Will resistance or ohms tell me anything? For instance say I put one probe on the wire near the light and one on the wire at the switch (using an extension), could resistance tell me if there was a screw/nail touching the wire?

This way I could narrow it down to a specific run of the wire.

johnthebuilder
Re: Received a shock froum the ground (dirt) outside my house

I used to work for a electric utility in Michigan (retired now). I had a complaint of high usage on the electric bill. I found the customer had a 3 way switch installed where a single pole should have been. He tied the ground to the 3rd screw so when he turned on the switch, the light worked but then he also had a ground condition, but it was not enough to blow the breaker ! Might want to check the wiring on the switch.
Let us all know what the problem was when you find it.

Jasondart
Re: Received a shock froum the ground (dirt) outside my house

I believe all wiring is the old "knob and tube" with no ground. I have to start investigating.

Vern Smith
Re: Received a shock froum the ground (dirt) outside my house

You are going to have to do some detective work. Since you know what breaker stops the problem, you need to begin at the breaker panel and try to trace the wire to each outlet. Somewhere, you are likely to find a wire with worn insulation that is touching either to other (neutral) wire or ground. FIX IT! This is a dangerous situation that could cause serious injury or death. Most older homes do not have GFI protection, and many do not even have a third ground wire installed. If in doubt, call an electrician to find the problem. The money you save on wasted electricity usage alone will make it worth the effort.

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