120v AC outlet hums

[Prairie]

I have a 2010 interstate 3500. The electric outlet behind the passenger seat on the port side hums, has a humming sound, when powered by the Triplite inverter. The sound is there even when there is no load plugged into the outlet. My wife hears this but I do not because I am hearing impaired. Does anyone know what might cause this? Of course, I am not using the inverter until this is resolved. Thanks for any suggestions.

[Protagonist]

Originally Posted by Prairie

The electric outlet behind the passenger seat on the port side hums, has a humming sound, when powered by the Triplite inverter. The sound is there even when there is no load plugged into the outlet.

Are you sure it's from the outlet? Some people with very sensitive hearing can detect a faint 60Hz hum from electrical devices. But there is no current flowing through an outlet until something is plugged into the outlet, so it should be impossible to hear the hum from an empty outlet.

[Prairie]

It seems hum when nothing is plugged into the outlet. And there is nothing else in the vicinity that would account for the noise. I'm stumped.

[gmillerok1]

Originally Posted by Prairie

I have a 2010 interstate 3500. The electric outlet behind the passenger seat on the port side hums, has a humming sound, when powered by the Triplite inverter. The sound is there even when there is no load plugged into the outlet. My wife hears this but I do not because I am hearing impaired. Does anyone know what might cause this? Of course, I am not using the inverter until this is resolved. Thanks for any suggestions.

I'm pretty certain that's a GFI outlet. Likely the hum is caused by the fact that it's being powered by a modified sine wave by the inverter, perhaps, if it only does it while on the inverter and not when connected to shore power. I upgraded to the Mangum Inverter/charger and highly recommend it. The Mangum is a pure sine wave, and has a smart charger that won't overcharge your house batteries, as the Tripplite will. It may get rid of the hum in the process.

[Prairie]

Thanks gmiller, yes it is a GFI outlet. However I've never noticed the noise before this trip (just started yesterday) and I use this outlet with the Triplite inverter every trip to power my c-pap device at night. Maybe the GFI outlet has bit the dust and should be replaced? My question now is, do I use it as is and ignore the hum until I get back or am I at risk of damaging something else? It's not very loud and I would never have noticed it if my wife had not called attention to it.

[clarklaflare]

Have you tried pressing the test button on the GFI and then resetting it?

[gmillerok1]

Originally Posted by Prairie

Thanks gmiller, yes it is a GFI outlet. However I've never noticed the noise before this trip (just started yesterday) and I use this outlet with the Triplite inverter every trip to power my c-pap device at night. Maybe the GFI outlet has bit the dust and should be replaced? My question now is, do I use it as is and ignore the hum until I get back or am I at risk of damaging something else? It's not very loud and I would never have noticed it if my wife had not called attention to it.

Apparently, the cheap Tripplite is putting out a waveform that the GFI doesn't like. You could try making sure all the connections are tight, but most likely, it a combination of a bad waveform (modified sine-wave vs. pure) and a cheap GFI. Replacing the GFI may solve the problem, as simply tightening the connections may do. You could replace the Tripplite with a Magnum. I bet the issue goes away that way, as well.

There is no risk in my opinion to anything else if you press the test button and can reset it. Better safe than sorry-if the above doesn't resolve it and you are your concerned about it-then replace it with a new GFI. Better yet, replace it AND the Tripplite. You will be glad you did.

[Prairie]

Thanks for all of your replys/suggestions.
I tripped and reset the GFI and nothing changed. Still hums/buzzes like before. I plan to leave the Triplite on for a while with my phone charger plugged in and see if it heats up the GFI or if anything changes. I'll replace the GFI outlet when time permits.
Thanks again and wish me luck!
Paul, aboard the Prairie Schooner

[73shark]

Since several outlets are connected downstream from this one, is there anything plugged in to them? If not, I'd consider replacing the GFIC outlet.

[Prairie]

Could low voltage on the house battery that feeds Tripp Lite inverter account for the humming sound in the GF I? I discovered today that the house battery is not charging while the engine is running as it should. I drove about 2 hours on the highway this morning and have only 11.3 V on the house battry. 11.8V when I started.

[gmillerok1]

Originally Posted by Prairie

Could low voltage on the house battery that feeds Tripp Lite inverter account for the humming sound in the GF I? I discovered today that the house battery is not charging while the engine is running as it should. I drove about 2 hours on the highway this morning and have only 11.3 V on the house battry. 11.8V when I started.

Yes, that's a possibility.

I had the same issue, caused by a loose connection where the positive (red) wire connects to the house batteries from the separator. All it took was a wrench to tighten it to fix it (well, that, and a 800 mile drive to Jackson Center to fix it among other things).

Your symptom of the house batteries not charging while the engine is on can only be caused by two things (guess I should add in my opinion):

1. Bad battery separator (unlikely).

2. A loose connection between the positive (red) wire on the battery separator or house batteries (very likely). Vibration, heat and cold cycles, and probably not a very tight connection to begin with contribute to this cause.

To check which one it is check connections on the red wire on the separator and where it connects to the house batteries while the engine is running for tightness and voltage. Note that the separator will not charge the house batteries until the chassis batteries voltage is above 13.2 vdc. With the engine running, and fully charged chassis batteries with the two banks connected, the lug with the red wire that goes to the house batteries on the separator should be measure 13.8 vdc on the separator. If it does not, then go to the front, remove the cover to the chassis battery box, and find the gang of wires and connections that are placed in the slot to the rear of the batteries, pull them out (you may have to remove a bolt or two) and find the red wire that goes to the separator. Check all the connections for tightness. If any are loose, tighten them. If tight, first check the voltage of the chassis batteries to see if they have a charge => 13.2 vdc with the engine running and then check the voltage on the line on the separator that runs to the front of the vehicle (red wire) while the engine is running as well as the red wire that connects it to the chassis batteries. Both should also be 13.8 vdc.With fully charged chassis batteries, you should hear a "clunk" as the separator connects the two after starting the engine, and it should be charging the house batteries. If not, the separator is not connecting the two when it should, and if the chassis batteries have more than 13.2 vdc, then it may be the separator itself.

If there is not 13.8 vdc at the chassis batteries, then it something else, including loose connections between there and the alternator, or a bad alternator. This is probably unlikely but if that's the case, I'd take it to a dealer at that point.

Note that the separator should make a "clunk" sound when the two are connected with the engine running, as the alternator should be charging the chassis batteries with 13.8 vdc. If the chassis batteries are not fully charged and hold less than a 13.2 vdc charge, it will not connect the two banks or charge the house until the chassis batteries have a charge greater than 13.2 vdc.

See:

http://www.cooperindustries.com/cont...ST_180126a.pdf (this is the model in mine, and I presume the same in the 2010, but if not, it will work in a similar way).

for more information about the separator. It's really not very complicated to troubleshoot it.

Finally, I am no expert like Lew; I only learned this when I a tech at JC fix the same problem for me while I watched. Also, be careful with those positive lugs when using a wrench. There's lot of amps there and you don't want to touch a ground while connected to the positive terminal unless you want to see some fireworks or weld something to the frame.

[BurntAsphalt]

Our 2011 Interstate has a humming GFCI as well. I never noticed it until a passenger tripped the outlet while charging a phone. TV stopped working too. When I reset it, I noticed the humming. I had an extra GFCI so I replaced the Hummer. The replacement would not reset, just stayed continuously tripped. Bought another one and it stayed tripped as well. Put the Hummer back in and reset it. It works but still hums. I have the Tripp lite inverter. I'm no electrician so other experts can chime in, but there are a few possible scenarios:
1. There is truly a fault and the humming GFCI is not tripping, which is a safety hazard
2. As gmiller suggested, the humming outlet is not crazy about the Tripp lite's modified sine wave and the new GFCIs don't have a clue what to do with a modified sine wave either
3. My AC voltage was reading about 100V on battery power (120V on generator) which is on the low side. I'm not sure if low voltage is a contributor to the problem (I did not have my Fluke meter (true RMS) at the time so it may just be meter was reading incorrectly as Mark Doane posted in another thread regarding my issue.)
4. None of the above

So long story short, don't be in a big hurry to replace the humming GFCI outlet. You'll likely be disappointed. Probably better to get the Magnum inverter and do it right. (That's #31 on my list of mods)

[sheriff1]

Originally Posted by BurntAsphalt

Our 2011 Interstate has a humming GFCI as well. I never noticed it until a passenger tripped the outlet while charging a phone. TV stopped working too. When I reset it, I noticed the humming. I had an extra GFCI so I replaced the Hummer. The replacement would not reset, just stayed continuously tripped. Bought another one and it stayed tripped as well. Put the Hummer back in and reset it. It works but still hums. I have the Tripp lite inverter. I'm no electrician so other experts can chime in, but there are a few possible scenarios:
1. There is truly a fault and the humming GFCI is not tripping, which is a safety hazard
2. As gmiller suggested, the humming outlet is not crazy about the Tripp lite's modified sine wave and the new GFCIs don't have a clue what to do with a modified sine wave either
3. My AC voltage was reading about 100V on battery power (120V on generator) which is on the low side. I'm not sure if low voltage is a contributor to the problem (I did not have my Fluke meter (true RMS) at the time so it may just be meter was reading incorrectly as Mark Doane posted in another thread regarding my issue.)
4. None of the above

So long story short, don't be in a big hurry to replace the humming GFCI outlet. You'll likely be disappointed. Probably better to get the Magnum inverter and do it right. (That's #31 on my list of mods)

I would say you have 2 problems, a defective GFI, they definitely should not hum, and a problem trying to trip the GFI that was successfully tripping good GFI.


2015 F350 CC 4X4 6.7 Diesel
2010 27FB Silver Cloud "The Silver Spoon"

[Prairie]

Thanks gmiller, I believe your analysis and suggestions may be the solution to my charger problem. However it is beyond my ability to carry out those procedures. I am in the process of contacting Orlando RV to set up a service appointment and will share your notes with them.
Another issue appeared this morning when the generator wouldn't start. It fires up and then dies after running about three seconds. The low oil warning light is not flashing.
So now I have further discharged the battery and have no place to plug in to recharge it.

[Protagonist]

Originally Posted by Prairie

Another issue appeared this morning when the generator wouldn't start. It fires up and then dies after running about three seconds. The low oil warning light is not flashing.

That happened to me a couple of years ago. The generator's voltage regulator was fried. Literally. The Onan dealer showed me the old one, and it had scorch marks on it.

While I had the generator in the shop to get that fixed, I had them install a resonator on the generator's exhaust pipe. Quieted things down quite a bit. At least from outside. It still sounds the same from inside, but that's because a resonator only quiets the exhaust, and does nothing for generator vibration, which is a major source of interior noise while the generator is running.

In a pinch, you should be able to charge the house batteries from the engine alternator, but you have to drive the van around for that to work; just idling won't do much.

[gmillerok1]

Originally Posted by Prairie

Thanks gmiller, I believe your analysis and suggestions may be the solution to my charger problem. However it is beyond my ability to carry out those procedures. I am in the process of contacting Orlando RV to set up a service appointment and will share your notes with them.
Another issue appeared this morning when the generator wouldn't start. It fires up and then dies after running about three seconds. The low oil warning light is not flashing.
So now I have further discharged the battery and have no place to plug in to recharge it.

Well, you can tell them how to fix it, then!

As for the genset, make sure there is propane available. Check to see if you can light (and stay lit for a minute or two as there is some gas under pressure in the line) the stove. If not, then it's not getting any gas. Check the switch to be the valve is turned on, and check the level of the propane. If the switch is on, and the meter shows you have plenty, then it could be something as minor as something in the line (I also had that problem at one time, or serious, as Progag mentioned. I don't know how many times, I've started mine, only to have it die in a few seconds, before I realized I did not turn on the switch to the solenoid valve. You can take it to a propane shop and they can check the lines for you. If it's not that, you will have to find a Onan dealer near you to troubleshoot and repair it.