Why would there be a 3 volt difference between the grounds on 2 buildings
that are wired to the same meter?

I have an out building at my house which is wired to the hosue but the
ground reads voltage between the house and the out building's wiring..

Is this usual?

thanks
- Mike

Yes,
If you want them at the same potential then you are going to
have to run a seperate ground wire from your out building to your main
buildings ground connection point. Depending on the distance will
deturmine the ground wires gauge. You can try adding a new ground rod
to your out building and your main building. A Hammer drill works great
for driving in ground rods. Re do and retighten all of your grounds.

RJ

In article , "Michael Kennedy"
wrote:

Why would there be a 3 volt difference between the grounds on 2 buildings
that are wired to the same meter?

I have an out building at my house which is wired to the hosue but the
ground reads voltage between the house and the out building's wiring..

Is this usual?

Mike-

The 3 volts is probably caused by different currents flowing in the two
240 VAC lines.

The difference current flows through the neutral wire back to the
transformer on the power pole, and a voltage difference will exist due to
the IR-drop. In other words, you are only measuring part of the circuit.
There is likely more voltage dropped between the transformer and the main
power box at the house.

Another interesting measurement is the difference between each side of the
240 VAC and neutral. I had a problem with bright flickering lights and
found there was a loose connection where the neutral wire connected inside
the main power box. If the connection had completely broken, there might
have been equipment damage resulting from unbalanced loads causing wildly
different voltages on the two sides.

Three volts sounds low, but it could be the symptom of a more serious problem.

Fred

Another interesting measurement is the difference between each side of the
240 VAC and neutral. I had a problem with bright flickering lights and
found there was a loose connection where the neutral wire connected inside
the main power box. If the connection had completely broken, there might
have been equipment damage resulting from unbalanced loads causing wildly
different voltages on the two sides.

Three volts sounds low, but it could be the symptom of a more serious
problem.

Fred

I was thinking that the neutral / ground wire might have a bad connection
and was actually worrying about exactly what you were saying.. I guess I'll
check out the neutral lug in the main breaker panel.

-Mike

Michael Kennedy wrote:

Why would there be a 3 volt difference between the grounds on 2 buildings
that are wired to the same meter?

I have an out building at my house which is wired to the hosue but the
ground reads voltage between the house and the out building's wiring..

Is this usual?

thanks
- Mike

Yes, earth has its own conductivity and voltage differences....
I read an idea just stringing a long wire east/west would generate
electricity...never tried it...
I know they tried it in space once...

But in La Canada, CA, my uncle built our home on a mountain in DG (decomposed
granite) and because of such long run of pipes, he made a really good
ground...said its from old days of farm houses that had lightning rods on the
barns....

He dug a 3-4 foot hole 1 ft. dia, then mixed up a batch of clay/sand/rock
salt to pour in it...and wet it with water......said the salt will permeate
further into the earth over time.......then used a 1" copper rod about 6ft
long and drove it into it..then connected a large clamp to our incoming water
pipe...then also continued the large wire to our incoming power box ground
with another clamp on the conduit and box....

He said lightning now has a very good path into the earth....and any galvanic
action between our water pipes and surrounding mineral deposits or other
neighbors pipes will be minimal....there's might all corrode away, but ours
wouldn't...??

We never had any problems...and my Crystal set radio with my 50ft antenna on
the roof worked great too!!

I once was in Malta on a wooden ship which had a full copper plated bottom
over the wood up to the water line...and any other ships docked nearby would
have all its zinc anodes dissapear very fast....and any steel fittings/props
etc. disolve away......very scary....big harbor battery's ha ha....

Copper rules.....

Now days there is actual meters which measure the electric current between
the ships hull and surrounding water, and can inject electric current to
diminish the galvanic action....helps kill marine growth too....
Having to drydock a large ship to clean hulls/replace zinc anodes isn't
cheap.....electrolysis sucks -

Gerry

"G.E.M." wrote in message
...
Michael Kennedy wrote:

Why would there be a 3 volt difference between the grounds on 2 buildings
that are wired to the same meter?

I have an out building at my house which is wired to the hosue but the
ground reads voltage between the house and the out building's wiring..

Is this usual?

thanks
- Mike

Yes, earth has its own conductivity and voltage differences....
I read an idea just stringing a long wire east/west would generate
electricity...never tried it...
I know they tried it in space once...

There wouldn't be any power generated unless a magnetic field was CHANGING
(cutting) thru your wire. The Nasa project was to see if they could change
the orbit of the satellite and conversely induce a current (generate
electricity) using a long wire and electricity.

You don't need to do it in space. We had the same effect on a longwire
antenna strung between two 150 foot towers about 150 feet apart. On a
"good" day you could draw sparks a couple of inches long.

G.E.M. wrote:

Yes, earth has its own conductivity and voltage differences....
I read an idea just stringing a long wire east/west would generate
electricity...never tried it...
I know they tried it in space once...

That's only one way to generate electricity. Have you heard of
electrostatic charges?

Jeff Rigby wrote:

There wouldn't be any power generated unless a magnetic field was CHANGING
(cutting) thru your wire. The Nasa project was to see if they could change
the orbit of the satellite and conversely induce a current (generate
electricity) using a long wire and electricity.