120VAC problems

[norwestie]

We plugging in to the 50A on the pedestal at a campground Sunday. Here is what happened right after:

(all related to 120VAC):

Several outlets dead
Vacuum cleaner pitch changed up and down when in use
Tower fan burned out (electrical odor noticed)
Coffee machine burned out, smoked noted
Touching exterior door handle, received mild shock

After the fan died and outlets not working, I reported the issue to the camp host. Maintenance man changed the 50 amp receptacle and checked voltage on all legs. All measured normal. When I reconnected, same problems noticed. I tried using my 50A-to-30A adapter and there was no AC power in the coach at all. I then disconnected shore power and ran the generator. Same lack of AC on various outlets. After I received a shock from the door handle, we ran from battery power only.
Perhaps unrelated but when I connected this RV at my home (before this trip) to a 15 amp 120VAC circuit, my GFCI would trip. My previous RV ran fine on the same circuit.
Do all of these point to one issue? I suspect the transfer switch but trust your input.

[Ranger Smith]

To burn stuff like that you have a bad neutral in the system. It can cause both legs to fluctuate. That is why the vacuum was changing speed. Could have been going up to 180 volts or more and other leg would be 60 volts.

[norwestie]

Ranger Smith, do you think the transfer switch could be the only culprit or something else?

[VI Roamers]

The 30 A connection did not work because you did not have a neutral to return the single side of the voltage back to the shore power. When you were connected to 50 A it is supposed to have a neutral connection in the middle, so each side of the connection carries 120 volt power.


As Ranger Rick said, you have your power leads connected, but your neutral was missing. The voltage then ran in series in one leg and out the other leg instead of in one leg and returning on neutral.


The cause of this needs to be determined without power being on the system. It could be in your plug, it could be a loose neutral where the wires coming from the plug are connected in the panel itself. The most likely cause is the plug itself. A few checks with a meter at the plug end and in the panel itself will likely tell the tale.

[Ranger Smith]

Originally Posted by norwestie

Ranger Smith, do you think the transfer switch could be the only culprit or something else?

I dont think it is the transfer switch itself as that usually just switches the "hots". Could be a bad plug or cord. Bad or burnt connection inside the transfer switch box. It all needs to be checked with NO power on the system. Seeing as how the generator acts the same way it is probably a bad connection inside the transfer switch box.


You should not plug in the rig till you find the issue as other things will blow with no return path on the neutral.

[JerryBrenner]

Could be a loose connection in the transfer switch.

[norwestie]

UPDATE
I took her to a repair shop I trust yesterday. Got a call later in the day that they were 99% sure they found the problem. Two of the house batteries were dead or close to it. He explained that when plugged into the 50 amp service, the inverter was trying so hard to charge the dead batteries that it caused havoc with the whole 120v system. All he did was to replace the four 12v batteries with four 6v GC-2s and everything works fine.
I watched as the park’s service guy checked voltage on both legs of the pedestal last week so it wasn’t a park issue. I hereby give up my electrical guru lapel pin.

[Ranger Smith]

I believe your issue is gonna show up again. I do not believe the inverter can cause a loss of the neutral leg which is what happened to you in your situation . . . But Im glad it is working now.

[jerichorick]

Originally Posted by norwestie

UPDATE
I took her to a repair shop I trust yesterday. Got a call later in the day that they were 99% sure they found the problem. Two of the house batteries were dead or close to it. He explained that when plugged into the 50 amp service, the inverter was trying so hard to charge the dead batteries that it caused havoc with the whole 120v system. All he did was to replace the four 12v batteries with four 6v GC-2s and everything works fine.
I watched as the park’s service guy checked voltage on both legs of the pedestal last week so it wasn’t a park issue. I hereby give up my electrical guru lapel pin.

I, too, am of the loose connection school. The inverter would have tripped a breaker if it was pulling too much current. Take the time to tighten all of the connections in the transfer switch and coach service panel. Make certain that the unit is unplugged and the generator circuit breaker is off. If the neutral is not making a good connection this could lead to a catastrophic failure of many of your AC appliances... microwave, inverter, etc. The tingle you felt when on the 15A circuit (should never use less than 20A service) is an indicator of a bad ground connection either in the coach or in the house.

[onholdguy]

Here is another thing that was taught in a class. Turn off the breaker on the power pole. Plug in your surge protector without the cord to the coach. Only the surge protector. Turn on the power and see what the surge protector reads. If everything is ok, turn off the breaker and plug in your power cord to the surge protector. THEN turn on the breaker. This assures that you have a good connection in the 50 amp cord and if you are just plugging it in it might be possible to plug in 1/2 and miss the netural leg and cause a problem.

[sajohnson]

Originally Posted by norwestie

UPDATE
I took her to a repair shop I trust yesterday. Got a call later in the day that they were 99% sure they found the problem. Two of the house batteries were dead or close to it. He explained that when plugged into the 50 amp service, the inverter was trying so hard to charge the dead batteries that it caused havoc with the whole 120v system. All he did was to replace the four 12v batteries with four 6v GC-2s and everything works fine.
I watched as the park’s service guy checked voltage on both legs of the pedestal last week so it wasn’t a park issue. I hereby give up my electrical guru lapel pin.

I'm afraid I have to agree with the others.

Inverters have their own internal protection circuitry, and as jerichorick mentioned, even if none of that worked, the circuit breaker feeding the inverter would have tripped.

The inverter 'trying hard to charge dead batteries' would not cause the exterior door handle to become energized, or fry other devices.

The tingle you felt could be a sign of a potentially deadly electrical fault. Here is a great source of info on RV electrical safety. THe author, Mike Sokol, really knows his stuff, and his articles are well written. You may find this one helpful:

Are "Little" Shocks OK? | No~Shock~Zone

[lewisedge]

Originally Posted by Ranger Smith

I believe your issue is gonna show up again. I do not believe the inverter can cause a loss of the neutral leg which is what happened to you in your situation . . . But Im glad it is working now.

I agree with Ranger Smith that this issue will show up again. Being shocked is good indication that your neutral is not being properly grounded. Although your batteries may also have needed to be replaced they should not have been causing all of your problems.

Lewis Edge, BS, EE, Georgia Tech

[Journey39n]

If you are getting shocked, touching metal, that indicates to me, that there is a short somewhere in the system. And if both the generator and shore power were having the same problem, the issue was on the coach side of the ATS, or in the coach circuit breaker box and/or wiring.

An 'inverter' that was trying too hard to charge dead batteries, does sound a little strange, they usually have sensors to avoid that sort of problem. Since replacing batteries seems to have solved the problem, I am wondering about the wiring at the batteries themselves.

And another problem, no one has mentioned, you have a converter that turns 120v to 12v to run things when you are plugged into shore or generator power. Remember, all your various electrical controls have computer chips in them, that run everything? They run on 12v. If your house batteries were bad, they would not be getting the proper current either.

I learned from my own experience. I saw some really strange problems when I had my house batteries finally die after 6 years. (co-incidentally, my engine alternator gradually went out and failed to charge the house batteries when driving, that accelerated the problem, I am sure)

Periodic lights dimming, things resetting, refer going off, Energy Management Panel acting erratically, etc., pretty much anything connected to the 12v system. When plugged in, or generator running, the converter seemed to keep things going most of the time. With a lot of testing, tripping breakers, and resetting components, I learned a lot. Big thing I learned was, that the converter can get hot, and will cycle off from time to time, letting the batteries pick up the load. Had to read the manual to find that out. Hard for dying batteries to pick up any load.

As we started the final leg of our trip, three stops to go before back to home area, the alternator totally failed, and we replaced it. Then with more testing, I determined I had bad house batteries. The next three days, I made sure either the engine was running (sending current to the batteries), the generator was running, (sending current to the charger and converter), or we were plugged into shore power, again current to the charger and converter.

Got to the end of the current trip, replaced my 4 GC2 batteries, and all was totally back to normal.

[al1florida]

Originally Posted by norwestie

We plugging in to the 50A on the pedestal at a campground Sunday. Here is what happened right after:

(all related to 120VAC):

Several outlets dead
Vacuum cleaner pitch changed up and down when in use
Tower fan burned out (electrical odor noticed)
Coffee machine burned out, smoked noted
Touching exterior door handle, received mild shock

After the fan died and outlets not working, I reported the issue to the camp host. Maintenance man changed the 50 amp receptacle and checked voltage on all legs. All measured normal. When I reconnected, same problems noticed. I tried using my 50A-to-30A adapter and there was no AC power in the coach at all. I then disconnected shore power and ran the generator. Same lack of AC on various outlets. After I received a shock from the door handle, we ran from battery power only.
Perhaps unrelated but when I connected this RV at my home (before this trip) to a 15 amp 120VAC circuit, my GFCI would trip. My previous RV ran fine on the same circuit.
Do all of these point to one issue? I suspect the transfer switch but trust your input.

Originally Posted by norwestie

UPDATE
I took her to a repair shop I trust yesterday. Got a call later in the day that they were 99% sure they found the problem. Two of the house batteries were dead or close to it. He explained that when plugged into the 50 amp service, the inverter was trying so hard to charge the dead batteries that it caused havoc with the whole 120v system. All he did was to replace the four 12v batteries with four 6v GC-2s and everything works fine.
I watched as the park’s service guy checked voltage on both legs of the pedestal last week so it wasn’t a park issue. I hereby give up my electrical guru lapel pin.

As I understand the sequence of events: You were in an RV Park when the problem first occurred. Then you took the RV to a place to have it repaired, but it sounds like you didn't go back to the RV Park and the same shore power pedestal where you had the problem.

Your original symptoms match a open neutral wire, either in the shore power pedestal, your power cord or inside the connections in the RV. It the problem was indeed the shore power pedestal, your problems are fixed unless you go back there. Open neutral can put 240 volts on some of your devices which are 120V only. It doesn't have to go to 240V, it can be somewhere in between 120 & 240. That would account for the vacuum cleaner sounds.


I can't explain the dead AC outlets when you turned on the generator. What did you do the fix that problem? That can't be fixed by new batteries. Although those outlets probably do go through the inverter with a transfer switch in the inverter so the outlets are powered by the inverter from the batteries or by the inverter directly from the shore power/generator.



When you say you watched the Park's service guy check the power and it was OK. Can you positively say that he read 120V from L1 to neutral and then safety ground pin, then the same for L2, and then 240V between L1 & L2. All the steps are important, not just that there is 120V on each leg.

NOTE: This is not to say you didn't have a bad battery. However you took your RV to have it repaired and they did find something wrong.

Also, obviously, if the problem was the shore power pedestal, there is no way the RV repair place would have found that problem. They fixed what they found.

[sajohnson]

Just a portion of the article I linked to above:

"An RV chassis and skin with ANY significant voltage above earth potential (2 volts is max) is proof that you’ve lost your RV’s safety ground connection. Now, by itself an open ground connection won’t cause an RV hot-skin voltage condition, but nearly anything inside your RV plugged into its electrical system will cause some leakage current to the RV chassis-ground. And that leakage will show up as a hot-skin voltage of varying degree. The really dangerous thing is that sometimes those can be high-impedance leakage currents that aren’t particularly dangerous. And that’s when you feel a “little” shock. However, that same “little” current can quickly become low-impedance/high-current leakage in a heartbeat, and that will almost certainly kill you if you touch the RV with wet hands and feet. It’s just a matter of degree, and you never know what that degree is. So any feeling of shocks from your RV or appliance is a warning to turn off the circuit breakers and disconnect the power plug immediately.

If you do have a proper RV safety ground back to the service panel, then it should be impossible to develop more than 1 or 2 volts on your RV skin. It will harmlessly drain away the small currents from normal high-impedance appliance leakage, as well as trip the circuit breaker form huge currents that result from abnormal low-impedance leakage, such as a screw driven through a wire inside your wall.

So if you measure more than 2 volts between the earth and the chassis of your RV there’s a serious problem with your safety ground. This is usually as simple as a broken or loose ground contact on your extension cord or dog-bone adapter, but can also be due to a problem in your campsite pedestal or home power outlet. Old garages are especially dangerous since they can be ungrounded for years without you knowing it, and the first time you plug an RV into it there can be a deadly hot-skin condition. And certainly a worn RV pedestal outlet can have corrosion or loose contacts, and that can cause an RV hot-skin condition."

Written by Mike Sokol:
Are "Little" Shocks OK? | No~Shock~Zone

There may be other problems as well, but getting shocked indicates there is an open (or resistive) ground connection.

That should be found and repaired ASAP -- before the rig is used again.

As others have mentioned, and as Mike points out:

"And certainly a worn RV pedestal outlet can have corrosion or loose contacts, and that can cause an RV hot-skin condition."

So your rig may be fine but it really should be checked out.

[CoveredWagon]

I recently had a similar issue with my 2005 the Sightseer 29R. When I plugged into 120V to use my A/C, I kept tripping breakers in shore power system. It didn't stay on long enough to burn anything.
After an hour or so with a multi-meter I located a problem. I was getting 120V feed through one of the white (neutral) wires. I identified the circuit and turned off that breaker. It solved my problem temporarily.
It seems that one my RV's GFCI outlets had failed and was shorting the system. After replacing that GFCI outlet the problem was solved!

[sajohnson]

Originally Posted by CoveredWagon

I recently had a similar issue with my 2005 the Sightseer 29R. When I plugged into 120V to use my A/C, I kept tripping breakers in shore power system. It didn't stay on long enough to burn anything.
After an hour or so with a multi-meter I located a problem. I was getting 120V feed through one of the white (neutral) wires. I identified the circuit and turned off that breaker. It solved my problem temporarily.
It seems that one my RV's GFCI outlets had failed and was shorting the system. After replacing that GFCI outlet the problem was solved!

So a GFCI outlet -- designed for protection against ground faults -- was actually causing the problem.

That's a new one.

Good job finding the cause!

[jerichorick]

Originally Posted by CoveredWagon

I recently had a similar issue with my 2005 the Sightseer 29R. When I plugged into 120V to use my A/C, I kept tripping breakers in shore power system. It didn't stay on long enough to burn anything.
After an hour or so with a multi-meter I located a problem. I was getting 120V feed through one of the white (neutral) wires. I identified the circuit and turned off that breaker. It solved my problem temporarily.
It seems that one my RV's GFCI outlets had failed and was shorting the system. After replacing that GFCI outlet the problem was solved!

I hope you sent it back to the GFCI manufacture. That is NOT a normal failure. Good troubleshooting.