125v vs. 117v revisited

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wrote:

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?
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On 12/28/2015 7:14 PM, snipped-for-privacy@aol.com wrote:

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
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wrote:

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.
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On 12/29/2015 8:40 PM, snipped-for-privacy@snyder.on.ca wrote:

8 volts difference, NOT 18 volts difference. I am guessing (not going out and measure) that the distance from box to box is approximately 140'. All I can tell you about the cable is that it says "AWG 2 AL TYPE VSE-2 60 MILS XLP INSULATED 500 VOLTS" and that it is black. It is buried approximately 4' deep and is not under a driveway. I do not believe there is a driven ground rod at the shop. I did just happen to put an 8' one in about three weeks ago for a "long wire antenna" for antique radios that I have and it was not fun.
I appreciate the advice but it has been working well for approximately eight years so nothing new is going to happen in the near future. We will be leaving state tomorrow for New Year's Eve parties, returning for a short period and then going to Florida until the beginning of March. During that period noting runs in the shop except the central propane fired hot air heating system.
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wrote:

I am sure you don't care but that is too small for 100a.
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On Tue, 29 Dec 2015 22:15:08 -0500, snipped-for-privacy@aol.com wrote:

Particularly with the AL in there. Sounds like aluminum, which needs to be upsized - and at 140 feet also needs to be upsized.
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On 12/29/2015 8:01 PM, IGot2P wrote:

*Measure* the potential between the neutral in your (workshop) box (or, at any free outlet) and this ground rod taking care NOT to short them in the process.

How do you KNOW that? Do you have a record of these observations/measurements that dates back to that time?? I.e., for all you know, this may be a recent development... or, related to the current loading, etc.

for fear something I've failed to consider will bite me in the *ss while I'm "away" from it!
Enjoy your trip!
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You must have some fairly heavy load in there. Yes, move some of the heavier loads to the opposite leg. Try to balance them. If you have a clamp around amp meter, put it on each main wire.
Do you have a green wire coming from the house? If not, you should have a ground rod, and I believe I read that anything over 100' should have one anyhow. When weather allows, I'd put in two ground rods and connect them with #6 bare copper wire.
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On Tuesday, December 29, 2015 at 8:53:00 PM UTC-5, IGot2P wrote:

What you're seeing is the symptom of a bad, partially functional neutral. With no load, the voltages measured between either leg and hot will be equal. As soon as you apply an unequal load on the legs, then current flows in the neutral and you see the voltages differ. The larger the load, the greater the difference. Tell us the amps flowing, the voltages you are measuring and we can tell you how large the resistance is that shouldn't be there. If the resistance is large enough and the current high enough, it's going to get hot, very hot. If you have a 5 volt drop and 100A, that's 500W at the point of the bad connection. How lucky do you feel today?
And rebalancing loads is just covering up the problem. It's only effective if the loads on each leg are equal and on at the same time. How are you going to achieve that?
Like others have suggested, probably time to call an electrician.
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On 12/28/2015 6:24 PM, IGot2P wrote: ...

You've isolated to you do not have an imbalance at one end of a wire and do at the other end...that's pretty clear evidence it's in the feeder or the connections there.
How did you run the feed line; possible you got a knick in insulation and are seeing moisture shunting effect in a buried line?
Of course, as gfretwell says, make the simple connection check first.
And, of course, there's still the issues regarding shared commons and grounds, building ground for the shop, etc., etc., ...
--


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On 12/29/2015 11:12 AM, dpb wrote: ...

..
And, if you cut off everything inside that box and the imbalance doesn't go away, you've proven it's in either the feeder itself or the connections, not a large imbalance in load in the box (altho that's pretty well proven already; you can just conclusively demonstrate it to yourself if there's no load and still and imbalance it's gotta' be either the feeder is damaged or the connections).
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On Monday, December 28, 2015 at 6:26:30 PM UTC-5, Don Y wrote:

Given that you have an imbalance at the subpanel, the obvious and easy next step is see if the imbalance exists at the service feed to the main panel. If it does, then call the power company.

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John G posted for all of us...

John, this is typical of this group. The posters want everyone else to do their work for them, then they argue and don't follow the information given and most times the result is never known. Follow along in the posts and you will see the offenders...
--
Tekkie

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Which only confirms what you were told a week ago by clare, gfretwell, trader, and I'm not sure how many other people: you have a bad neutral connection.
Since you don't seem to understand how this works, or the level of danger involved, I recommend you hire a qualified electrician to find and fix the problem ASAP before your house burns down.
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No, it probably doesn't. And the problem isn't what's coming from the power company anyway. The problem is that his neutral connection is bad.
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On Wed, 30 Dec 2015 12:15:58 -0800 (PST), Uncle Monster

The problem with your solution is the voltage at the "main" panel in the house has no problem. He has a problem between the main and the sub. Underszed feed (for the length) and inballanced load could explain it. Otherwize he has a neutral problem.
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On Wed, 30 Dec 2015 12:15:58 -0800 (PST), Uncle Monster

My saying an undersized fead and inballanced load could cause it would only be because the neutral was overloaded by the inballance. With a properly balanced load the neutral carries NO current.
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On Wednesday, December 30, 2015 at 8:04:45 PM UTC-6, snipped-for-privacy@snyder.on.ca wro te:

I think you have a hybrid word "imbalance" and "unbalance"? (or I'm not com petent in Canadienese) (ಠ_ృ)
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On Wed, 30 Dec 2015 18:29:58 -0800 (PST), bob_villain

Yea, it should have been spelled Imbalance. I used to be a very good speller in my younger days - last one standing in spelling bees, but there are more words now, and I've let my spelling slip - and generally don't use spell-check.
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On Wed, 30 Dec 2015 23:45:50 -0500, snipped-for-privacy@snyder.on.ca wrote:

There are a lot less words now if you listen to that garbage Rap Music the kids listen to these days. They can write an entire 5 minute song using only 3 or 4 vulgar words!
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