I have an issue with my grounding system in my home.
I had the cable company out last week to troubleshoot a Box that wouldn't
work. The Cable Guy told me I had a ground issue, the cable wire sparked
when he Disconnected it from the box then re-connected it.
I have a grounding rod outside my house, just below the Meter. The Phone,
Cable, and Breaker Box are all connected to it. I confirmed that there was
in fact 120v showing on my multimeter at the Grounding Rod.
I also noticed that the concrete floor in the basement was warm near the
vicintiy of the grounding rod.
I disconnected the Phone & Cable wires from the grounding Rod. Still
showing 120v on my multimeter.
I went inside the house and turned off the 200A Main Breaker. Checked the
grounding rod and it is still showing 120v on my multimeter. Even better,
the meter is still spinning even though I turned off the main breaker.
Any suggestions on what to do? Should I my electric co? I want to get this
taken care of.
Thx in Advance,
It;s going to be next to impossible to diagnose this over the
internet, especially given the complete lack of details. Given that
the electric meter spins with the main breaker open, and if you're
indeed not a troll, then I would call the electric company as a first
OP using a digital meter? you can get all sorts of flakey readings
from digital meters.
try lighting a light bulb.......
ground loops can generate voltage between grounds.
I would start by calling power company, how old is the bservice
*Yeah that happens. A few thoughts come to mind.
1) The cable wire is coming in contact with a live wire somewhere.
2) You have a loose or separated neutral conductor somewhere such as your
main panel, the electric meter, your service point of attachment at the top
of the house or at the pole.
3) One of your neighbors has a loose or separated neutral conductor
somewhere such as their main panel, the electric meter, their service point
of attachment at the top of the house or at the pole.
The fact that the meter still spins with the power off is not much help.
Sometimes they do that. What I would do is put an ammeter around the main
grounding conductor to see if there is any current flowing. However in your
situation I suggest that your first step is to call the power company and
have them take a look.
Do you also have a water pipe ground connection at the water meter location?
I would check the current flow on that too.
How close is your house to the power company's transformer?
I can't figure out how a meter would spin with the main breaker open. If
the neutral current was being measured I could see a possibility, but
far as I know utility meters don't. Meters don't even have to connect to
Other that that, I agree with what about everyone has said, including it
could be an open neutral for the OP, or with a water pipe ground an open
neutral at another house. Also that it could be a troll.
Years ago, some folks I knew, their electric bill seemed
high. The electrician replaced the big wire between the
meter, and the circuit panel box. Corrosion had set in. He
showed us with a VOM, that there was connection between the
two big hot legs.
I agree. The OP should call the utility company. However, if
the fault turns out to be on his side of the demarc, they
may shut off all of his power until he can get it rectified.
However, chances are high that it's a utility problem and
they will likely fix it promptly at no charge.
| Malcolm Hoar "The more I practice, the luckier I get". |
Thanks for all the responses! Let me try to answer all of the questions that
I measured the 120v AC on an analog multimeter. This was measured between
the disconnected cable box ground wire and the connector on the cable
box(connects to the ground on the splitter). I know the voltage isn't
coming from the cable side since there is no current present after I
disconnect the groundwire.
Most people on my street aren't grounding to their water pipes since we use
wells that have black plastic pipe coming into the house.
Again, this is about as clear as mud. I've yet to see a cable box
with a "ground wire". You probably mean you're measuring between
the cable box coax connector and the metal of the the connector on the
end of the coax cable, but who knows. Given weird things are going
on, you sure wouldn't be the first person who had some crazy wiring
scheme going on.
Again, totally unclear what exactly this means and how you are
Call the electric company before something bad happens to someone.
While you may have other problems causing the situation, the one thing
that does seem certain is that there is a ground problem here. The
AC system ground and the cable ground should be tied together near the
service entrance. And if they are, then you couldn't be getting 120V
between the cable coax ground and the AC ground.
The supplied picture makes things a lot clearer. What was being
referred to as "the cable box", is actually the surge arrestor on the
cable at the entrance point. Getting a spark and measuring 120V
beteween the arrestor and the ground wire means one of two things:
A - The cable ground is actually hot because somewhere else it's
contacting 120V, like back out at the street, neighbor's house, etc.
B - The cable is in fact grounded correctly and whatever the ground
wire is connected to is not ground but is elevated to 120V. That
could be occuring if the ground wire is connected to some other
grounds, one of them is supplying the 120V due to some fault, and the
ground wire does not have an actual ground to earth.
I would measure between the disconnected incoming cable and a good
known earth ground seperate from the ground this ground wire is
supposed to go to. A metal water pipe coming into the house would be
one choice. Alternatively, you could drive a length of pipe or
similar into the ground, apply some water as a temporary ground. Then
I'd measure between the ground wire and the new earth ground. One
of them is going to have 120V and whichever it is, you'll know who's
problem it is.
The cable guy, having been there, should have determined this before
leaving. Also, be careful, as you're obviously dealing with an
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