On Tuesday, November 3, 2015 at 10:21:48 AM UTC-5, dpb wrote:
On 11/03/2015 9:21 AM, Ralph Mowery wrote:
wrote in message ...
OK, I've had a continuing hassle develop w/ the ground in the old barn
over the last year or so.

Finally, about two months ago I replaced the ground rod w/ new and all
seemed well. As of about a week ago, the gremlin is back--there's enough
to light a couple 100W bulbs at not quite full intensity and outlets
measure full 125V but not enough current to power motors, etc. Clearly
it's the ground as all the 240V gear is fully functional.

It's _extremely_ hard to fathom a new rod can have gone south so quickly
and we've had sufficient rain that it certainly is the case of excessively
dry ground.

Yesterday I ran a jumper directly from the ground bar in the circuit box
to the ground and made no difference whatsoever in the symptoms.

It is _all_ 120V circuits, not just one so seems as though not possible to
be a failed breaker not passing current; but for the life of me I can't
figure out another common-mode cause...

Anybody got any ideas or ever had such a symptom? I may end up calling
the pro on this one...was out just last week to help find a broken
underground feeder to another of the outbuildings; too bad the symptom
hadn't reared it's head again then or woulda' had him take a look then.

--

What are you doing depending on a ground rod to carry the current that a
neutral wire should be used for ?

YOu should have at the least 3 wires and really 4 wires comming from the
house (or whever the power is comming from) going to the barn. If you do
have 3 wires or more, the neutral wire is broken or a bad connection
somewhere.

Early '50s installation 3-wire; nobody ever heard of 4-wire back then.

The neutral is tied to the ground, of course.

It's that there's a direct connection from the box bypassing the
connection/path that's been there since day one that runs back up the
entrance conduit to the weatherhead at the roofline and comes back down
to the ground rod that I bypassed to verify the connection at that point
wasn't the failure. It's about 30 ft off the ground so not that
convenient if can otherwise eliminate it as the issue.

Don't see how there's not a complete circuit here.


Presumably when larger loads are put on it, the voltage drops.
So, get a heater or similar, and plug it in. Then start measuring
voltages from hot to neutral, tracing back. At the heater it will
be well below 120V. Someplace up the chain it will be 120V, normal.
Then between the two, apparently something is wrong with the neutral.
The neutral current is in a conductor and it should not be a ground
rod problem.