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Unbalanced load problem (at home)

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ijf0

New Member
SYMPTOMS: When I run a slightly unbalanced load on my 120/240v split phase US home I get a substantial voltage drop on the loaded leg and a equally substantial voltage JUMP on the opposite leg.
If I balance out the load, the voltages return to normal.

EXAMPLEs: If I run the microwave (rated ~13amps) on the black leg, the voltage on the same black leg drops from 123 to about 109 and the voltage on the red leg jumps to 133.
If I then run the vacuum (rated ~12amps) at the same time but on the red leg the voltages on both red and black legs return to 122-123ish range.
If I then stop the microwave on the black leg (now only the vacuum on the red leg is running) the voltage on the red leg drops to about 110 and the voltage on the black leg jumps to about 135.

All the while the voltage from red to black remains around 245

I dont know if this is a typical phenomon or not but it has become very prominent over the last day. At one point this morning when the microwave was running I briefly saw the voltage on the microwave circuit dip below 100v (maybe my roommate had her curling iron on or something). Anyone have a clue what I should look for????
At first I thought it was my microwave going bad, but now that I've plugged in other larger loads (vacuum, toaster, space heater) I find that it happens with all of them ...
I havent blown any fuses (yes, I still have a fuse panel -- tho its on my list to upgrade to a breaker box) but I have gone as far as literally removing ALL of the fuses from the panel EXCEPT for the microwave circuit and the same occurs.
 

Mike_2545

Super Moderator
Check the Neutral wires in the breaker box. Make sure they are tight at their connections. Best to pull the Main breaker when doing this check.

Edit: (Fuse Panel)
 
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tcmtech

Banned
Most Helpful Member
You definitely have a bad common line connection.
There is a great electrical fire danger present now.
Get it looked at immediately!
 

ijf0

New Member
Is it possible a bad connection might exist on the entrance cable somewhere? Like at the meter or even at the power company's transformer?

Thus far I have not found a bad connection in my fuse box :confused:
 

Mike_2545

Super Moderator
Absolutely, if the problem is not in the house fuse box, a bad connection could easily exist at the meter or further down the line, at the pole. (If you have aerial wires)
 

ijf0

New Member
might this be indicated by the fact that under the example test conditions above I read the same voltage measurements (for drops and swells) on the main lugs in the fuse box?

would it also help to determine if the same problem occurs on multiple/all branch circuits in the house?
 

ijf0

New Member
Emm k
So RG&E was out today (or so they claim -- because of course they didnt call so I could meet them) and says that everything checked out fine. So where do I go from here? I had to setup a seperate arrangement with them to come out on Friday to pull the meter so I can check connections there and also futz around inside my fusebox and tighten any connections. But what if I dont find anything??? Where do I look next?

How come this 120v split phase stuff is making 480 3phase seem easy??? :p

I talked with my boss at work and upon his suggestion checked the ground connections and connections to the H2O pipe. Here's what I found/did:
I have 1 ground rod thats driven into the ground at a dirt portion of my basement (not sure how deep the ground rod is, but it looks like its probably been there for a while.
There was no connection through to ground at the water meter and the green ground (which i assume is provided by the water company) that comes in alongside the water pipe (plastic of course) was just hanging loose. I got a ground clamp and have connected that green ground to the load side of the water meter (copper pipe throughout house).
I also ran a green ground wire from the neutral/ground bar in the fuse panel (not seperated) to this ground clamp on the water pipe.
Here's the fun part: if i put an amp clamp on the ground wire between the panel and the water line i see about 2.3 amps ... when i run the micro it jumps to 12.2

I know thats not right.

The utility is arguing with me now that its my problem, but can't I safely stand my ground and insist that its AT LEAST at the main lugs in the fuse box or prior to them? They play like its an act of congress to get a guy out here to pull the meter so I can look and test from there (aparently the line crews cant do that, gotta have a special guy:eek:) but darnit i'm raedy to clip their little tag off and pull it out myself (haha, one of the customer service reps on the phone today told me if I turned the main breakers off I could disconnect the meter myself ... should have gotten her name)


Thanks for all your help guys, its much appreciated. :)
 

Mike_2545

Super Moderator
There was no connection through to ground at the water meter and the green ground (which i assume is provided by the water company) that comes in alongside the water pipe (plastic of course) was just hanging loose. I got a ground clamp and have connected that green ground to the load side of the water meter (copper pipe throughout house).
That is a trace wire, not a ground wire. They put a RF signal on it and can detect the location of the buried plastic pipe in the ground.
 

Sceadwian

Banned
You could call an electrician in to track down the problem, if it turns out to be in the house you're gonna be stuck paying for it no matter what, but if the electrician can prove that it's something outside of the house you should be able to take the power company to small claims court to recoup the cost. Just mentioning that you're planning on doing that over the phone may get you more attention. At this point I wouldn't be talking with the standard representatives that answer the phones, you should probably be demanding to talk with a supervisor as something is obviously very wrong.
 

ijf0

New Member
0amps through the ground rod
I think HD and Lowes have 4 or 6' ground rods, I'll probably get 4 or so of them and drive them into the ground. BUT I dont think that will help with this problem... will it?

WHY ON EARTH (no pun intended) would the H2O company use a green wire as their tracer??? LOL. I see a green wire going into the cement wall i assume ground. But Mike is right as the current is NOT passing through this wire to get to ground ... Learned something today. Thanks Mike. ;)

Should I still be checking wires inside the house (like at outlets and things) for a poor neutral connection?

Oh this is frustrating. :mad:
Thank goodness I dont draw a big load.
 

ijf0

New Member
On second thought ... haha ... maybe I should just turn everything on that I possibly can and wait for the stupid magic smoke
 

Willbe

New Member
from 123 to about 109 and the voltage on the red leg jumps to 133.

All the while the voltage from red to black remains around 245
245/2 = 123

123-109 = 14v
This is how much there is across your bad neutral. There should be less than 1v.

At 13A this is 182w, but other loads on the other side of the neutral will reduce this 13A. If it's a loose bolted connection it should be pretty hot.
 
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Sceadwian

Banned
Wire color is never standard, at best they're guidelines. You have an IR thermal cam that's great, I was gonna suggest it but I never thought you might actually have access to one, they're about 10grand or so.
 

mneary

New Member
If you have 0A through your ground rod with a huge differential voltage on your neutral, then your ground rod is not doing its job. You're on the right track to get four of the 6' ground rods and drive them in. Consider using #8 (or four #12) back to the fuse box neutral/ground, hopefully less than 12 feet or so.
 

Gaston

Member
i had the same problem. the power company didn't care. they wouldn't even send someone out.at the splice were the nuetral coming from the transformer tieing into the nuetral going to my panle, the wire was old and frayed. i took some heavy wire like a 1/0 and some of those u bolt clamps and jumped the bad part. never had a problem since. i don't recomend you do this though unless you are aware of the dangers and how to prevent them.
 

ijf0

New Member
I had the thermal cam home over the weekend but didnt find any obviously hot neutrals in the panel, outside at the meter, at the power head, or out to the pole.

When I ran the microwave to give the unbalanced load of 109v/136v I only saw a slight temp increase (few deg F) in some of the fusing and the actual circuit wire.

When i started the dryer, however, i didnt find any hot neutrals but DID see the main lugs where the entrance cable ties in were hot. Hotter than the branch fuses feeding the dryer.

RG&E is supposed to be out Friday to pull the meter for me (they told me all I could do was look [because I have no permet/inspection], but hopefully they'll let me put some anti-corrosion goop on the wire and re-torque without much fuss). I have a feeling this isnt my entire problem. I'll see if I cant get those ground rods today on my way home.

Thanks again for everyone's help.

If ground rods and re-torqueing doesnt help ... i think i'll call in someone who knows more about residential wiring than i do ... stupid split phase.
 

tcmtech

Banned
Most Helpful Member
stupid split phase.
Would you like a 7 lead six phase set up instead? :confused::D

I would say you still have a common line problem some place between the panel and the service transformer. Does it feed any other houses or places?

When the service people do come over to inspect I would first unplug every thing that feeds from one side of the system and then plug it all into the other side. Go and borrow every electric heater you can get too! Push the line voltage imbalance way way off!

Do it a half an hour or an hour ahead of when they show up. That will get the problem spot so hot that they shouldn't be able to miss it! ;)
 
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