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DawnAndChris · 09-24-2013, 08:48 PM

We have a 50amp 240 volt generator. It has two breakers, a 20amp and a 30amp. The 20amp breaker keeps kicking, and there is something else....

When both breakers are closed, I get 120 volts on each leg, and all is right in the world.

When the 20 amp breaker is open, I get 120 volts in leg1... and leg2 still has 20 volts! I thought/think this means there is a short somewhere, and leg1 is somehow energizing leg2 with a small voltage. Does this theory sound right?

Further more, I have broken leg2 in several places, and have a seemingly dead wire, that sill reads voltage! One side of the break reads 8 volts, the other side reads 13 volts. And on a second break, the one side still reads 13 volts and the other reads 20 volts!

I did find where a screw had been put through the wires. I broke the wires at this point to make a repair. I am looking for more issues, but begining to question my data at this point.

Any thoughts as to what might be going on??? I am attaching a picture to try to illustrate my data.

vsheetz · 09-24-2013, 08:52 PM

What is the initial problem with the genny?

DawnAndChris · 09-24-2013, 08:59 PM

The 20 amp breaker keeps kicking without an apparent load.

wa8yxm · 09-25-2013, 05:03 AM

First, the 20 amp breaker is SUPPOSED to run ONE air conditinoer, nothing more... Some of them are miswired with the 20 running the house and the AC on the 30

As for the 20 volt.> Bleed is a good word,, NO LOAD (note that term as it is important) NO LOAD, capacitive coupling between the wires can give you up to sixty volts.

Put a bit of load on it (Night light for example) and zero happens.

bruceisla · 09-25-2013, 05:22 AM

Quote:

Originally Posted by wa8yxm

First, the 20 amp breaker is SUPPOSED to run ONE air conditinoer, nothing more... Some of them are miswired with the 20 running the house and the AC on the 30

As for the 20 volt.> Bleed is a good word,, NO LOAD (note that term as it is important) NO LOAD, capacitive coupling between the wires can give you up to sixty volts.

Put a bit of load on it (Night light for example) and zero happens.

Good advice ... the 20 "ish" volts is likely to be an induced voltage at a very low current from another source in close proximity. As suggested, a load (lamp) will probably make it zero volts. This will not fix your problem may may eliminate troubleshooting confusion.

Are you sure you didn't already fix your problem (screw thru wire)?

DawnAndChris · 09-25-2013, 09:57 AM

Thanks wa8yxm!

Actually, you were right about the 20 amp breaker being mis-wired. It was going to the house on a 30 amp breaker. When I first saw that, I was certain I had fixed the problem, but alas... not so much. At least we have alieviated the symptoms. We never run the AC and when it kicks, we loose nothing.

I was worried there was a short somewhere causing unseen damage, possibly threatening the rig and maybe getting worse - even though we can comfortably leave the breaker off.

Thanks bruceisla!

Inductive load huh.... When I first saw the 20 volts (and with the breaker still kicking), I thought maybe there was a short and that the 20v was a sign of it. But as I began breaking the circuit and seeing all this weird volatage, I definetly began to wonder about an induction possibility.

I DID find one screw, and it did pierce one of the hot legs inside. I knew this was a problem, but wasnt convinced it was "thee" problem because it didnt expose leg 2. (back on my energizing leg 2 theory).

Thanks to you both!!!

I will re-evaluate with this new information.

bruceisla · 09-25-2013, 10:40 AM

Quote:

Originally Posted by DawnAndChris

Thanks wa8yxm!

Actually, you were right about the 20 amp breaker being mis-wired. It was going to the house on a 30 amp breaker. When I first saw that, I was certain I had fixed the problem, but alas... not so much. At least we have alieviated the symptoms. We never run the AC and when it kicks, we loose nothing.

I was worried there was a short somewhere causing unseen damage, possibly threatening the rig and maybe getting worse - even though we can comfortably leave the breaker off.

Thanks bruceisla!

Inductive load huh.... When I first saw the 20 volts (and with the breaker still kicking), I thought maybe there was a short and that the 20v was a sign of it. But as I began breaking the circuit and seeing all this weird volatage, I definetly began to wonder about an induction possibility.

I DID find one screw, and it did pierce one of the hot legs inside. I knew this was a problem, but wasnt convinced it was "thee" problem because it didnt expose leg 2. (back on my energizing leg 2 theory).

Thanks to you both!!!

I will re-evaluate with this new information.

And thank you! ... we always appreciate feedback.
Let us know what you find.

myredracer · 09-25-2013, 12:56 PM

Hi Chris, I think you have some pretty good answers here.

I think what you might be seeing is what is sometimes called "ghost voltage" caused by voltage induced onto a conductor from an adjacent one. If you used a low impedance type voltmeter you probably wouldn't measure anything. Most multimeters nowadays are the high impedance type. This link should give you some insight:

http://http://www.fluke.com/fluke/us...+impedance.htm

wa8yxm · 09-25-2013, 04:25 PM

I too thank you for the feedback... I consider it "Capacitive couplling" but inductive works as well.

Here is what is happening.. A Capacitor is a device that passes AC but not DC, it consists of two conductive "plates" seperated by an insulator.

Or in your case. The red wire, and the black wire, and the insulation surrounding them. It is also called inductive coupling.

Normally it can not pass a whole lot of current.. but then I've been put on my....pride... by a metal gate attached to a woven wire fence staked in place with steel posts driven in the ground (Can you say very well grounded) because the weave of the wire formed a perfect transformer and an electric fan motor was "Coupling" to the fence.

DawnAndChris · 09-25-2013, 05:49 PM

Thank you myredracer.

I do appreciate everyone's help!

I definetly think the Capacitive couplling was not a symptom of the problem. I just didnt know any better at the time. I have since checked all the wires for continuety, and they all look fine. No more shorts seem to exist.

If the breaker continues to pop, I think my next step will be to replace the breaker.