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Open Roads Forum  >  Tech Issues

 > 30 amp 240 volt mistake!!

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BB_TX

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Posted: 05/04/19 03:52pm Link  |  Quote  |  Print  |  Notify Moderator

cavie wrote:

BB_TX wrote:

If you used a standard 50/30 dogbone adapter be aware that the adapter connects both hot legs of the coach together. Meaning you put 240 on both hot legs, not just one.


You can not put 240 volts down both legs. A 30/50 adaptor takes the one 30 amp 120 volt leg and puts that 120 volt leg on the 2 120 volts legs of the 50 amp cord. 120 volts @ 30 amps down both legs.

A 50/30 adaptor takes just 1 50 amp leg and put in down the 1 hotleg of a 30 amp cord.

you can not get 240 volts on one leg of a service in the US and Canada. That only happens in european countries.

An adapter to connect a 50 amp RV to a standard 30 amp outlet connects the 30 amp hot leg to BOTH of the 50 amp RV hot legs. The two hot legs are connected internally in the adapter. Otherwise if you connected a 50 amp RV to a park 30 amp outlet you would only have 120 vac to half the RV. And that just ain’t how it works. And that type adapter is what he said he used. I said 50/30. Thank you for the correction to 30/50.

westernrvparkowner

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Posted: 05/04/19 03:54pm Link  |  Quote  |  Print  |  Notify Moderator

cavie wrote:

mxdad777 wrote:

BB_TX wrote:

If you used a standard 50/30 dogbone adapter be aware that the adapter connects both hot legs of the coach together. Meaning you put 240 on both hot legs, not just one.

That’s what I used, however when I tested both buss bars only one had 240v. The other bar was dead.


You did not have 240 on 1 buss bar, you had 120 on the buss bar and 120 on the neutral. 240 between hot and neutral.
You are new to these forums. You will soon discover that with all the misinformation about electrical service it is a wonder that natural selection hasn't cleaned out the well meaning, but erroneous posters. You are absolutely correct in your diagnosis, but it will be lost in a sea of erroneous posts.

mxdad777

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Posted: 05/04/19 03:56pm Link  |  Quote  |  Print  |  Notify Moderator

cavie wrote:

mxdad777 wrote:

I changed the welder receptacle to one that would fit my RV. My mistake was thinking both the 30amp and 50amp RV outlets were both 240v. I knew everything in the RV ran off of 120v, but figured it was the same configuration for both 30 and 50. When I tested the buss bars in the panel, I indeed had 240v on one leg and zero volts on the other. I checked the glass fuse on the fridge circuit board and unfortunately the fuse is good. My guess is the circuit board is toast. Since the microwave and AC unit seem to be working fine, I’m hopeful the only damage was to the fridge. I think my converter should be fine, because it’s fed off the buss bar that had zero power going to it.


You did not have 240 one leg. You had 120 on one leg and 120 on the neutrals.

Yes, you are correct. That’s what I meant, just worded it poorly. One bus bar was dead, one had 120v plus the neutral had 120v giving me 240v for everything tied to the one buss bar.


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Acampingwewillgo

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Posted: 05/04/19 04:07pm Link  |  Quote  |  Print  |  Notify Moderator

westernrvparkowner wrote:

cavie wrote:

mxdad777 wrote:

BB_TX wrote:

If you used a standard 50/30 dogbone adapter be aware that the adapter connects both hot legs of the coach together. Meaning you put 240 on both hot legs, not just one.

That’s what I used, however when I tested both buss bars only one had 240v. The other bar was dead.


You did not have 240 on 1 buss bar, you had 120 on the buss bar and 120 on the neutral. 240 between hot and neutral.
You are new to these forums. You will soon discover that with all the misinformation about electrical service it is a wonder that natural selection hasn't cleaned out the well meaning, but erroneous posters. You are absolutely correct in your diagnosis, but it will be lost in a sea of erroneous posts.


Unless I'm reading this wrong, the OP certainly is Not new to this Forum. I can't count how many times a similar situation has been asked and answered. But I do agree that most everyone on here gets caught up in the nuances of it all so pick and chose wisely if looking for an answer. Being an electrician yourself, I'm sure you now have a more complete understanding of what went wrong, the only issue now is to discover the damage and I believe that's what your asking about. No need to pile on the OP's mistake and make an argument about it. Of course, JMHO! :-)


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cavie

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Posted: 05/04/19 04:22pm Link  |  Quote  |  Print  |  Notify Moderator

westernrvparkowner wrote:

cavie wrote:

mxdad777 wrote:

BB_TX wrote:

If you used a standard 50/30 dogbone adapter be aware that the adapter connects both hot legs of the coach together. Meaning you put 240 on both hot legs, not just one.

That’s what I used, however when I tested both buss bars only one had 240v. The other bar was dead.


You did not have 240 on 1 buss bar, you had 120 on the buss bar and 120 on the neutral. 240 between hot and neutral.
You are new to these forums. You will soon discover that with all the misinformation about electrical service it is a wonder that natural selection hasn't cleaned out the well meaning, but erroneous posters. You are absolutely correct in your diagnosis, but it will be lost in a sea of erroneous posts.


I am very aware of the misinformation given out on these forums. I do my best to put a stop to it when I can. Newbie diy's read it on the internet and think it must be correct! Non professional electricians just don't know all the things that go on with electricity and how very dangerious it can be. Hot skin on an RV kills people and starts fires. I personally believe dogbones need to be outlawed but that ain't gonna happen. The statement made in this thread about 240 volts on both legs sent me thru the roof!!!! The one I had the worst is the 100 amps available BS That's a whole seperate thread. but I'll keep tippen them pedestals.


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jkwilson

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Posted: 05/04/19 04:30pm Link  |  Quote  |  Print  |  Notify Moderator

cavie wrote:

BB_TX wrote:

If you used a standard 50/30 dogbone adapter be aware that the adapter connects both hot legs of the coach together. Meaning you put 240 on both hot legs, not just one.


You can not put 240 volts down both legs. A 30/50 adaptor takes the one 30 amp 120 volt leg and puts that 120 volt leg on the 2 120 volts legs of the 50 amp cord. 120 volts @ 30 amps down both legs.

A 50/30 adaptor takes just 1 50 amp leg and put in down the 1 hotleg of a 30 amp cord.

you can not get 240 volts on one leg of a service in the US and Canada. That only happens in european countries.


This is only true if you plug into a 120V circuit. OP plugged into a 240V outlet, which would have put one 120V circuit on both hots going into the RV and then the other 120V circuit on the RV neutral. This makes both sides of the 50A circuit in the RV 240V.


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mxdad777

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Posted: 05/04/19 04:31pm Link  |  Quote  |  Print  |  Notify Moderator

You’re exactly right. I now am more educated with RV wiring and understand what caused the problem. I am pretty thick skinned though, so the piling on doesn’t bother me. [emoticon]. Yes, my concern now is fixing what was damaged. That’s the process I’m going through now.
My biggest concern is the fridge. Since all fuses I can find on the back of the unit are good, I’m assuming I fried the circuit board. I’ll be taking it out soon to inspect. The converter was on the dead side so I should be fine there. The microwave and AC unit were on the hot side, but both seem to be working fine. Onward I go...

Hurricaner

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Posted: 05/04/19 04:36pm Link  |  Quote  |  Print  |  Notify Moderator

Lets get back to the ops problem. Is this a rv refer or a residential refer? A rv refer uses 12 volts for the control board so the refer should still work on gas. If it is a residential refer than you need to replace the control board.

Sam


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2naEagle

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Posted: 05/04/19 04:41pm Link  |  Quote  |  Print  |  Notify Moderator

mxdad777 I'm sorry to hear about what happened. Sometimes a education is expensive.
Look into getting a EMS
Here is you a little reading material.
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wa8yxm

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Posted: 05/04/19 04:45pm Link  |  Quote  |  Print  |  Notify Moderator

BB_TX wrote:

If you used a standard 50/30 dogbone adapter be aware that the adapter connects both hot legs of the coach together. Meaning you put 240 on both hot legs, not just one.


Perhaps not. From teh sounds of it he mayu have a 50 amp RV (He mentioned two legs) if he has a 30 amp he needs a proper 30 amp at 120 volt outlet.

FOlks we caution about this all the time.. Though it's been low volume of late I recall a few years ago We would get 3 - 5 per month with the same sad story... Many welder outlets WILL take a 30 amp RV plug no matter what folks say bout "THEY ARE DIFFERENT".. They are not different enough

Many professionals look at the TT-30 outlet and say "OH 240 volt" I managed to instruct one before he fried his client but.. How many are there? (his client got lucky)

I wired my own.. PROPERLY.. But I have training.


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