On Tue, 29 Dec 2015 19:53:01 -0600, IGot2P
wrote:

On 12/28/2015 7:14 PM, wrote:
On Mon, 28 Dec 2015 18:24:50 -0600, IGot2P
wrote:

On 12/28/2015 5:56 PM, wrote:
On Mon, 28 Dec 2015 18:51:14 -0500, "Ralph Mowery"
wrote:


"Don Y" wrote in message
...
On 12/28/2015 4:04 PM, John G wrote:
Don Y has brought this to us :

Do the *easy* things, first.
- measure at the *main* panel
- measure at the subpanel (already done)
- open the disconnect at the subpanel and remeasure at the main panel
Assuming this isolates the problem to the subpanel:
- remove individual loads from the subpanel (open breakers) and measure

Take good notes.

You should be able to diagnose the problem just from these observations.

It has taken an unbelievable amount of drivel and misinformation to get
down to
this simple list of things to do to isolate the problem. :-?

I am basically lazy. : As I think most folks are. I would rather do
the easy things -- take data and THINK about the problem -- than run
around "try this", etc.

Occam's Razor: chances are, it's something in the subpanel/workshop
and NOT something with the utility -- *or* the main panel (not
counting the subpanel tie-in).

Eliminate the workshop and see if the problem persists. If not, tells
you the problem is *related* to the workshop (though may still manifest
in something else).


Often it is easy to determin if it is a neutral problem. Meter both sides
of the AC. Then with almost everything cut off, plug in a large load such
as a bathroom heat or hair dryer to one side. If the unloaded side changes
voltage it is almost sure to be a neutral problem somewhere.

YOu can do this in the workshop, then move to the house.
If workshop and not house, it is probably your problem, if also at the house
and on the main wires, if the neutral is not loose at the box, probably the
power company problem



Generally speaking, checking at the service disconnect is about as far
as you can go because everything on the line side of that is sealed by
the PoCo. They will generally fix anything on that side for free, just
to keep you out of the metering equipment. Obviously if they determine
it is on the line side of the service point (typically the crimps on
the drop or the transformer connection on a service lateral), it is
their baby anyway.

Okay, to the few who have stayed on subject...first I checked most of
the outlets in the house and they all read in the 122v range. I then
opened the house breaker box and both sides coming in read 122.7v. I
also checked the voltage coming out of the breaker that goes to the shop
and they also read 122.7. I also tightened all three wires down that go
to the shop (actually none were loose). I THINK that this tells me that
the problem is in the shop but we are currently in the middle of a
rain/sleet/snow storm here in the Midwest so I am no going back out to
the shop to look in that box again tonight. In fact, we were totally
without power part of this afternoon...the ice probably took a limb down
over a line.

Thanks for all of the help and let me know if you agree that the problem
is in the shop.

You have determined that it is in the neutral in the feeder. It might
even be worth disconnecting it AFTER YOU TRIP THE BREAKER for that
feeder and examine both ends of the wire for corrosion etc.
Then examine the lug and reinstall it.

I also did not notice a ground rod connection at the shop end. If you
are setting the "way back" machine to a time when 3 wire feeders to
additional buildings, you were still required to drive a rod. With
that much of a voltage drop in your neutral, you are putting voltage
on the case of all of your equipment.
A ground electrode will mitigate that a bit.
If you really want to address the violations you can also separate the
wires on the ground bus (one for each screw) you have plenty of
spares. You can double or triple up the grounds in most panels but not
the neutrals. They need their own screw.
What size wire is that feeder?


Okay, the feeder wire is #2 if I am reading the writing on the wire
correctly.

I shut all of the power down and loosened the neutral in the main box in
the house and then reset it and tightened it up very tight. It did not
appear to be loose or corroded before or after I did this. I also
checked once again that the the hots coming out of the 100 amp breaker
in the main box in the house were tight and they were.

Now to the box in the shop. I attempted to tighten the hots but they
were already as tight as they would go. I then loosened the neutral,
checked for corrosion (there was none) and re-tightened it.

After doing the above I checked the voltages again and had the same 125
and 117 as I originally did so no joy.

Then I shut all of the breakers off in the shop panel including the main
100 amp breaker and checked the voltages again. Now things had changed
and I had 122v and 120v!

To this layman it appears that it is just difference in the load on the
two legs that is making the difference but now that the difference is
down to two (2) volts I think that is close enough. I suppose that I
could move some of the load from one leg to the other and even things
out somewhat. Of course it would depend upon what was turned on at any
given time.

Thanks to all who helped,

Don
If you have 2 volts difference with no load, and 18 volts with a
load, you DO have a neutral problem - The fact that the high side
comes down and the low side goes up with no load proves it HAS to be a
neutral problem. There is no other possibility. How long is the feed
from the main to the sub? What kind of cable did you use? How deep is
it burried? Is it direct burial cable or in a conduit? Is it running
under a driveway?

Something is still not adding up. Also, do you have a driven
ground??? If not, get one in there and test again.