Home electrical help please.

[CobyRupert]

Does turning one of the two breakers off have any effect on the other one?? It could be that a shared ground (grounded/neutral) wire has a bad connection.

This is what I 1'st suspected, except:
- You would tend to get an overvoltage on one leg (L1), and an undervoltage on the other (L2) that adds up to 220/240 volts. (- although I suppose, a loose connection could then cut this to the 206V (108V + 98V) that the OP measured.
- Hopefully his house doesn't have multiwire ciruits that share a neutral run from (2) single pole breakers (located on opposite sides of the panel.) This would be unlikely.

I'd still do the test, it can't hurt.

Check for loose breaker
I was also going to say check for loose connections. Do you have aluminum wiring? Have you had large loads plugged into outlets lately, like say an A/C? Has it been really hot there lately? - But if you measuring 98V right at the terminal of the breaker (and not just at a receptacle) then maybe this is not your problem.

If your measuring 98V at breaker terminal, turn off breaker, remove branch circuit wire from breaker, turn breaker back on and remeasure voltage at breaker terminal. If it's still 98V and all other breaker's are at 120V, then the breaker (or it's connection to the panel) is the problem and not the circuit wiring.

Edit: ^ Sort of the same thing EddieWalker said as I was typing this (but in reverse order).

 

[s219]

Twice I have had a breaker fail down at my pier due to some insect that gets inside the breaker, then makes some sort of cocoon. Eventually it grows big enough to mess up the breaker.

I keep the breakers off until i need to use a circuit (one is 220V/20A for boat lift, and the other is 110V/15A for a receptacle).

The first time I heard sizzling noises when flipping the breaker, and the lever wouldn't close all the way. Replaced the breaker and tore it apart to discover why. I figured maybe I had worn out the breaker using it as a switch, but no, it was the darn insect inside! I think I posted a thread here on TBN.

The second time it happened in a 2-3 day period after I installed the new circuit for the receptacle and before the inspector was coming over. Right after install, it tested fine. I went down with my GFI tester a day later to verify the GFI tripped, and the lights indicated a fault. Lots of head scratching, as it just was fine a couple days earlier. Got out my voltmeter and was only seeing 90-95V on that circuit. Went around in circles a bit then tested the breaker to determine it was the problem. Replaced it, took apart the old one, and saw the same insect/cocoon inside. Anyhow, that's the point of my ramble, is that a bad or contaminated breaker can indeed give you low voltage on the circuit.

If this happens another time, I guess I need to figure out how to seal up the breaker box or breakers (the breakers all have a small air vent molded in them which I assume is important, but that's obviously how the bugs get in).

 

[Carhartt Cowboy]

Some of the guy got close....

You have a loose neutral (the white wire). The cause is a bad connection. If it was only one circuit it could be in either the hot or neutral but since you have a problem with two it is in the shared neutral.

And yes I'm a licensed master electrician.....and a degree or two..but those may make me dumber....

 

[kenmac]

Some of the guy got close....

You have a loose neutral (the white wire). The cause is a bad connection. If it was only one circuit it could be in either the hot or neutral but since you have a problem with two it is in the shared neutral.

And yes I'm a licensed master electrician.....and a degree or two..but those may make me dumber....

I had a loose neutral on an electric water heater once... That thing gave me fits .
Sometimes it would work , some times it wouldn't.
I finally found the loose connection in a junction box

You can get some screwed up volt meter readings with a bad neutral .

 

[CobyRupert]

Some of the guy got close....

You have a loose neutral (the white wire). The cause is a bad connection. If it was only one circuit it could be in either the hot or neutral but since you have a problem with two it is in the shared neutral.

And yes I'm a licensed master electrician.....and a degree or two..but those may make me dumber....

Maybe...But it hasn't been established there is a shared neutral. And there shouldn't be one. ....if there was a shared neutral w/ a bad connection, you would tend to get an overvoltage on one of the circuit legs (L1) and an undervoltage on the other circuit leg (L2) that added together = 240 volts. [The voltage measured in each leg (in reference to the floating neutral, not the panel ground), would be determined by the impedance of the loads turned ON in each leg (i.e. With a disconnected/floating neutral, the loads on L1 & L2 are now in series with each other on a 240V circuit, instead of each being pegged at 120V to neutral/ground. The 240V is now split across L1 & L2 circuit loads in accordance with their impedance).] - A picture would do a better description than words.

What is interesting is he's doing these measurements with no loads turned on, i.e. no way for L1 and L2 to be in a 240V series circuit (which is what you'd have if you had a lifted neutral.)

He's also measuring 98V at the panel in reference to the panel ground, not at a remote receptacle in reference to a (floating/loose) neutral.

I hope the OP let's us know.

-...and that's my 2 cents

 

[Carhartt Cowboy]

Maybe...But it hasn't been established there is a shared neutral. And there shouldn't be one. ....if there was a shared neutral w/ a bad connection, you would tend to get an overvoltage .....


-...and that's my 2 cents

It has been established by the facts he has presented. Also, you seem stuck on the 'overvoltage' thing, let me explain, he is measuring with everything unpluged. Also, I would wager and say both breakers are on the same phase.

 

[CobyRupert]

It has been established by the facts he has presented. Also, you seem stuck on the 'overvoltage' thing, let me explain, he is measuring with everything unpluged. Also, I would wager and say both breakers are on the same phase.

...ok. Don't get me wrong, I'm not arguing, just kicking ideas around. Let's say they're the same phase, & he is measuring with all loads off or unplugged. Meaning there's no current, and without current, there's no voltage drop across a loose connection: so how do you get a reduced voltage reading anywhere, even at the breaker?

Even if they're not the same phase and the branch circuit's common neutral is lifted, you should still read 120V to (panel) ground at each breaker terminal as long as the panel ground is bonded with the transformers center tap. You just wont read 120V to (now floating) neutral.

Maybe we have to go back to Eddie's question: Is OP measuring voltage in reference to the same ground/neutral on every measurement?

 

[ben2go]

I am doing this with all loads off the circuit.

I can't find any shared neutrals.They are all in their individual slots in the break box.Here is what I did today.I pulled every outlet,switch,and light fixture.Nothing obvious wrong and everything was clean and tight.So I went and bought one replacement breaker.I shut off the main breaker in the panel.I replaced the breaker that had the lowest voltage.When I went to turn the main breaker on,the little lever just flopped around as if it were connected to nothing.There was no resistance in the breaker lever.I shut the power off at the main disconnect outside at the power meter.So, I went and bought a new Siemens 100 amp main breaker and installed it.While I was at it,I cleaned all the terminals and sanded them lightly with fine sand paper.I also went through every thing in the panel checking for corrosion and tightening everything up.At this point I have a new main breaker and a new breaker on the lowest voltage circuit.All of the breakers in the panel are off.I flipped the main on, and reset the breaker with the lowest voltage,and I got nothing.So I kept resetting breakers, until I have power at the lowest voltage breaker.When I rest my 220v 20a water heater breaker,I all of a sudden have power to that side of the elec panel.This breaker is above four of the 120v breakers.When the water heater breaker is tripped,they all loose poser on that side.The thing is,my water heater has it's own circuit.Now I am completely stumped.

There is no aluminum wiring in this house.The main power feed,from the main shut off to the elec panel, is aluminum.Not my preferred choice but it was here when I got the place.

 

[Carhartt Cowboy]

^^^^ Lets state a few of ohm's laws. 1. current is same measured anywhere in the circuit. 2. Voltage is different at each spot in a circuit, all voltage drop in a circuit equals the total voltage applied to the circuit i.e. 120V.

He is measuring voltage (pressure) not current (flow). You can have pressure and no flow.

The bad connection has resistance, the balance of the 120V is being dropped (used up) at the bad connection. This is why he is reading low at the places that should be a solid ~120.

All the low readings he has taken are at the outlets not the panel. If he measures between the breaker and a good ground he will get his 120. This is because he has removed the bad connection from the circuit he is measuring.

 

[ben2go]

^^^^ Lets state a few of ohm's laws. 1. current is same measured anywhere in the circuit. 2. Voltage is different at each spot in a circuit, all voltage drop in a circuit equals the total voltage applied to the circuit i.e. 120V.

He is measuring voltage (pressure) not current (flow). You can have pressure and no flow.

The bad connection has resistance, the balance of the 120V is being dropped (used up) at the bad connection. This is why he is reading low at the places that should be a solid ~120.

All the low readings he has taken are at the outlets not the panel. If he measures between the breaker and a good ground he will get his 120. This is because he has removed the bad connection from the circuit he is measuring.

I am getting low voltage at the breakers.Around 94-98v at one and 108-112 at the other.It's also not steady and goes up and down a couple volts either way.