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Old 01-14-2022, 09:01 PM   #1
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Powering 50 Amp 5th Wheel Wheel With 30 Amp 240 Circuit

Bought an adapter off Amazon to temporarily supply power to my Forrest River Sierra. Wasn't getting power to any of my outlets. Voltage checked cord all the way to the connection at the trailer and was getting 240v pole to pole. An hour later a I heard a high pitch sound and then smoke. Assume it must have been the inverter. New to all of this and just assumed I could feed the trailer with a 30 Amp double pole circuit. I'm no thinking I assumed wrong. Lol! Any help would be greatly appreciated.

Justin
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Old 01-14-2022, 09:18 PM   #2
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Nothing in an RV is 240 volts. Take a better picture of the prongs on that adaptor. Nothing i have ever seen? was that purchased with camping accessories or generator?

If you plugged your camper into a 240 volt circuit like a dryer or stove you did serious damage to your camper. Step down one more time to a standard house hold outlet and you can run anything but the a/c

30 and 50 amp rv plugs are not 240 volt
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Old 01-14-2022, 09:26 PM   #3
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Not enough detail on how you wired it to troubleshoot.

There are many prior posts on how to correctly wire 50 amp and 30 amp RV receptacles.

Here is one sample: https://www.forestriverforums.com/fo...ll-204006.html
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Old 01-14-2022, 09:35 PM   #4
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Plugged it into my L14-30 receptacle (fed by a 30 Amp double pole breaker) I have in the garage. Not sure how wiring this is any different than a 50 Amp rv receptacle. Both are fed by a double pole breaker.
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Old 01-14-2022, 09:52 PM   #5
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I am betting you fried alot of stuff, a 50 amp TV connection is has 2 hots a nuetrul and ground, it has 2 120 volt 50 amp circuits, the two legs are out of phase so the neutral never has more than 120 volts/ 50 amps on it. What you did is not good. My guess is you used an outlet for a 240 volt welder which does not have a neutral.
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Old 01-14-2022, 09:59 PM   #6
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I am betting you fried alot of stuff, a 50 amp TV connection is has 2 hots a nuetrul and ground, it has 2 120 volt 50 amp circuits, the two legs are out of phase so the neutral never has more than 120 volts/ 50 amps on it. What you did is not good. My guess is you used an outlet for a 240 volt welder which does not have a neutral.
I used an outlet with a neutral. Same one I use to back feed my generator power through. It's an L14-30
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Old 01-14-2022, 10:02 PM   #7
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Follow the testing on the outlet testing tab at https://www.myrv.us/electric/ at the end of the adapter, where you plugged in the 5er power cord, to see if you are providing the correct voltages at the adapter.

You want to see 240v, 120v, and 0v between the different legs as shown for a 50 amp plug, presuming you used a L14-30P Locking Male Plug to 14-50R Amp Female adapter.
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Old 01-14-2022, 10:52 PM   #8
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Tell us more about the red plug adapter you were using.

Your thought process is correct.

A 50a R/V feed is indeed 240v and fed with a double pole breaker.
There are two hot legs (L1 & L2) a neutral and a ground.
Those saying it isn't 240v are incorrect.
The R/V has a breaker box that DOES NOT allow the use of both legs together so your R/V only ever sees the 120v in the branch circuits from each separate leg.

Internally, a 240v R/V outlet with four poles is wired exactly like a 50a 240v four pole outlet in a home.

A 30a R/V feed is 120v with one hot leg (L1) a neutral and a ground and fed with a single pole breaker.

Connecting a R/V to a 30a 240v outlet such as those older THREE pole dryer/welder outlets with two hot legs (L1 & L2) and a neutral and fed with a double pole breaker is a HUGE NO NO and will cause things to burn up.

If you truely fed your 50a R/V from a FOUR pole 30a twist lock outlet and the adapter was wired correctly so the L1 & L2, neutral and ground went to the respective locations on the R/V plug it should have worked fine. You would have simply been limited to 30a on each leg. (L1 & L2)

My guess is either the adapter was internally wired incorrectly or the 30a 240v twistlock receptacle you plugged it into was wired incorrectly.
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Old 01-14-2022, 10:57 PM   #9
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Follow the testing on the outlet testing tab at https://www.myrv.us/electric/ at the end of the adapter, where you plugged in the 5er power cord, to see if you are providing the correct voltages at the adapter.

You want to see 240v, 120v, and 0v between the different legs as shown for a 50 amp plug, presuming you used a L14-30P Locking Male Plug to 14-50R Amp Female adapter.
I did. I just never checked hot to neutral as I would have caught it right away. I found the problem. One of the two extension cords with l14-30 plugs was only a 3 conductor. It was missing the neutral. Replaced that one with a four conductor and everything seems to be working. All tv, receptacle, microwave. Can't get the electric fireplace to work. Will fool with that in the morning.

The 3 conductor with the l14-30 plugs was actually for my welder that doesn't have a neutral. Lol! Still strange that I got smoke be not having a neutral though. I guess the inverters (caps) are sensitive to this? Seems kind of cheesy. Anyway, thanks for everyone's help.
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Old 01-14-2022, 11:31 PM   #10
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Without a neutral, the inverter should be seeing no input voltage, as most are only wired on a single 120V leg.
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Old 01-15-2022, 04:07 AM   #11
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Originally Posted by Jacain View Post
I did. I just never checked hot to neutral as I would have caught it right away. I found the problem. One of the two extension cords with l14-30 plugs was only a 3 conductor. It was missing the neutral. Replaced that one with a four conductor and everything seems to be working. All tv, receptacle, microwave. Can't get the electric fireplace to work. Will fool with that in the morning.

The 3 conductor with the l14-30 plugs was actually for my welder that doesn't have a neutral. Lol! Still strange that I got smoke be not having a neutral though. I guess the inverters (caps) are sensitive to this? Seems kind of cheesy. Anyway, thanks for everyone's help.

It sounds like you have gotten more than 120 volts on a single leg with all of your extension cords/adapters. Basically you had an open neutral. The smoke you saw was most likely your converter blowing up, which happens in these situations. It is going to need replacing.

The other things that can be damaged are the microwave, television, refrigerator control boards, electric fireplaces, and any other 120 volt AC item that may have been plugged into an outlet. Usually the air conditioners are spared unless you turned them on during this bad hookup. With an open neutral it depends on what was on what leg.


Once you got connected correctly, your 12 volt DC items (lights, pumps, fans, slides, etc) are still going to function but they are drawing directly from the RV's battery now and not the smoked converter. Once your battery runs down, these items are going to stop working since your converter is also your battery recharger. You can hookup an automotive style battery charger and recharge the battery until the converter is replaced.

Please read these links below to understand the differences between converter/inverter and also what an open/missing neutral does in a 120/240 volt split phase connection

https://www.forestriverforums.com/fo...nt-152813.html

Click this link below and then the 'open neutral' tab on the left.

https://www.myrv.us/electric/
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Old 01-15-2022, 06:17 AM   #12
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It sounds like you have gotten more than 120 volts on a single leg with all of your extension cords/adapters. Basically you had an open neutral. The smoke you saw was most likely your converter blowing up, which happens in these situations. It is going to need replacing.

The other things that can be damaged are the microwave, television, refrigerator control boards, electric fireplaces, and any other 120 volt AC item that may have been plugged into an outlet. Usually the air conditioners are spared unless you turned them on during this bad hookup. With an open neutral it depends on what was on what leg.


Once you got connected correctly, your 12 volt DC items (lights, pumps, fans, slides, etc) are still going to function but they are drawing directly from the RV's battery now and not the smoked converter. Once your battery runs down, these items are going to stop working since your converter is also your battery recharger. You can hookup an automotive style battery charger and recharge the battery until the converter is replaced.

Please read these links below to understand the differences between converter/inverter and also what an open/missing neutral does in a 120/240 volt split phase connection

https://www.forestriverforums.com/fo...nt-152813.html

Click this link below and then the 'open neutral' tab on the left.

https://www.myrv.us/electric/
Thanks for the link. I wouldn't have guessed in a million years that an open neutral would cause this problem. Makes you wonder why they don't incorporate some sort of protection (neutral detection) into the converters.
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Old 01-15-2022, 06:43 AM   #13
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Thanks for the link. I wouldn't have guessed in a million years that an open neutral would cause this problem. Makes you wonder why they don't incorporate some sort of protection (neutral detection) into the converters.
You may still not be understanding what your missing/open neutral did. The converter runs off of 120 volt AC, and is usually just plugged into an outlet, but can be hardwired. It would be like say a hair dryer, you plugged into a bathroom outlet.

When you used an extension cord without a neutral (or if a neutral goes open), then there is nothing that keeps the two sides of a 120/240 split phase service into the TWO separate 120 volt legs. You could have 0 volts on one leg and 240 volts on the other. You could have 40 volts on one leg and 200 volts on the other...etc etc.

It sounds like the converter and any other 120 AC volt item being fed by the same line got more than the 120 volts as designed. That is not something that usually happens, and it was caused by you. It's one of those things that happens and is a learning experience for all those reading this. It will help others in the future.

This is one of my favorite links to help those understand 120/240 volt split phase wiring and the common neutral shared between the L1 and L2 sides.

https://www.rvtechmag.com/electrical/chapter3.php

and this diagram may also help you visualize it. When you left out the neutral, you left out what keeps L1 and L2 both at 120 volts. As stated, you could have 200 volts on L1 and 40 volts on L2 or any combination thereof depending on what was turned on during your mishap. N-L1 is 120 volts, and N-L2 is 120 volts....but if you take out the neutral(aka open) then, there can be 240 volts on L1 or L2 and anything connected will be burned up with the 240 volts



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Old 01-15-2022, 07:34 AM   #14
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Originally Posted by Jacain View Post
Bought an adapter off Amazon to temporarily supply power to my Forrest River Sierra. Wasn't getting power to any of my outlets. Voltage checked cord all the way to the connection at the trailer and was getting 240v pole to pole. An hour later a I heard a high pitch sound and then smoke. Assume it must have been the inverter. New to all of this and just assumed I could feed the trailer with a 30 Amp double pole circuit. I'm no thinking I assumed wrong. Lol! Any help would be greatly appreciated.

Justin
You stated below that you connected to an outlet that runs your welder which more than likely is 240 and that is a no no. Glad you did not ruin your converter.
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Old 01-15-2022, 07:42 AM   #15
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You may still not be understanding what your missing/open neutral did. The converter runs off of 120 volt AC, and is usually just plugged into an outlet, but can be hardwired. It would be like say a hair dryer, you plugged into a bathroom outlet.

When you used an extension cord without a neutral (or if a neutral goes open), then there is nothing that keeps the two sides of a 120/240 split phase service into the TWO separate 120 volt legs. You could have 0 volts on one leg and 240 volts on the other. You could have 40 volts on one leg and 200 volts on the other...etc etc.

It sounds like the converter and any other 120 AC volt item being fed by the same line got more than the 120 volts as designed. That is not something that usually happens, and it was caused by you. It's one of those things that happens and is a learning experience for all those reading this. It will help others in the future.

This is one of my favorite links to help those understand 120/240 volt split phase wiring and the common neutral shared between the L1 and L2 sides.

https://www.rvtechmag.com/electrical/chapter3.php

and this diagram may also help you visualize it. When you left out the neutral, you left out what keeps L1 and L2 both at 120 volts. As stated, you could have 200 volts on L1 and 40 volts on L2 or any combination thereof depending on what was turned on during your mishap. N-L1 is 120 volts, and N-L2 is 120 volts....but if you take out the neutral(aka open) then, there can be 240 volts on L1 or L2 and anything connected will be burned up with the 240 volts



Thanks again for the references. I think I see what happened. The unit was out of propane and the slides were in, so didn't want to use the electric fireplace since we are going to get snow. I put a space.beater in to keep things a little warm until I could get everything winterized correctly as I just brought it home from the inlaws. I bet she. I connected the heater and had the switch on it did it. That would allow the circuits on the other pole to see the potential from the leg the heater was connected to as they share the neutral via the RV circuit pannel.

I just checked both ac units and they still work. Thank God. I don't think my hot water heater is dual fuel, so it is probably ok unless the electrics fried on that. Will check it in a bit. Furnace blower comes on too. Just need to get the tanks refilled and make sure all that fires up. Hopefully the electric fireplace can be repared with a replacement control board.

The converter likely blew a cap. I know they are only usually rated for a certain voltage and the increased voltage probably overcame the dielectric film capacity/rating. Hopefully converters aren't too expensive.

I haven't even owned the camper for a year. Lol! Moral of the story, educate yourself as much as you can so you understand these nuances and never be in a hurry! That's what caused the problem in the first place. If I had only verified voltage from leg to neutral before I plugged it into the camper....smh.
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Old 01-15-2022, 07:54 AM   #16
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One more thing, it definitely makes sense to feed both hot legs of the camper 50 Amp plug with a single pole circuit. That way both legs are in phase and you can't get more voltage if you lose the nuetral.

Oh, and any suggestions on a converter brand model if I end up having to replace this one on my dime? Might be a good idea to upgrade. Then again, I might get lucky and they cover it under warranty even if it was my fault. Good family owned smaller RV dealer where I bought it from. I think the model I have now is a Progressive Dynamics PD9100/9200. Thanks again for all of the help!

Justin
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Old 01-15-2022, 08:23 AM   #17
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Now that I think about it, I bet it was the fan on the converter that burnt up. The sound it was making makes sense. If it's still working, but the fan burnt up, the 12v fridge should still show power with the battery disconnect open. Will try that here in a little bit. �� Fan will be easy to replace.
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Old 01-15-2022, 08:32 AM   #18
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You stated below that you connected to an outlet that runs your welder which more than likely is 240 and that is a no no. Glad you did not ruin your converter.
The open neutral is what caused the problem. I understand how the space heater did it now. Thanks to wmtire for helping me with the references. I had that plug made up so I could just use the welder via my 4 prong L14-30 twist lock receptacle I use to feed my panel with generator power. The welder doesn't use a neutral, so I just mad it up with a three conductor cord. From now on I won't have any three conductor cords laying around with l14-30 plugs. I'll probably make up a new welder cord that uses 4 conductor so I can never make the same mistake again no matter what. Also, definitely going to verify leg to neutral power everytime I hook up the camper to shore power.
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Old 01-15-2022, 08:45 AM   #19
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Glad you were able to determine the cause of your issue and hopefully the damage to your converter and fireplace is minimal. You mentioned that there should be some protection from an open neutral. Many folks including myself use a EMS system that does protect your rig from an open neutral and low/high voltage as well as surges. Well worth the cost. Mine saved me this past season from an open neutral on a post. Maintenance replaced the worn out receptacle and all was well. There are three brands that are widely accepted they are Progressive, Surge Guard, & Hughes. They are available in both portable and hard wired versions. I am using the Hughes hard wired unit and can recommend that. When I had a 30 amp coach I had the Progressive unit and also had no issues with that one.
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Old 01-15-2022, 08:45 AM   #20
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One more thing, it definitely makes sense to feed both hot legs of the camper 50 Amp plug with a single pole circuit. That way both legs are in phase and you can't get more voltage if you lose the nuetral.

A 50 amp RV is designed to use a NEMA 14-50R outlet. The breaker box inside the RV keeps everything at 120 volts when wired correctly upstream of it. Study the previous diagram again and you will see this. Here is another to help:




If the RV was fed by only a 50 amp single pole circuit, you would only be able to get 6000 watts to the RV. By using the double pole 120/240 circuit, the RV can power up to 12000 watts.
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