30 amp 240 volt mistake!!

[mxdad777]

I recently bought a 2018 Rockwood 5th wheel with a 50 amp service. I have a 240 v 50 amp outlet in my RV cover that I’ve used for years to plug my motorhome into. Since I still have my motorhome and it’s parked in the RV garage I decided to hook up my 5er temporarily to my 30 amp 240 volt welder outlet. I had no idea that RV 30 amp cords were 120v only. Long story short, after connecting my 30 to 50 adapter I sent 240 volts down one leg of the buss bar. So everything on that side of the bus bar received 240 volts while the other side received zero. My question now is what will I need to replace? My refrigerator, GFCI, rooftop A/C were all on that side. The A/C seems to be working fine, but the fridge isn’t and the GFCI is smoked. Although I’ve wired up many homes, I certainly learned something about RV’a and their wiring today. I’m hoping just the circuit board on the fridge can be replaced. Anyone else have any experience with this? I’m sure this can’t be the first time this has happened. Stupid me!!

[mxdad777]

Ok, after replacing both of my GFCI receptacles it appears everything works except for the refrigerator. It looks like all outlets ran through the GFCI receptacles first and so they became the sacrificial child. Lucky there, $40 and I’m back in business for most of the RV. The converter is fine because it was on the buss bar that received no power. So my fridge is the problem. I know I have good power to the fridge receptacle, but the fridge is giving me an error code E3. I get the code regardless if I try LP or 120v. The make is Dometic and the model is RM1350SLMX. I googled E3 code and it talks about a recent button, but I don’t believe this fridge has the reset button I read about. Any ideas how to clear the E3 code or is my circuit board toast?

[CA_Traveler]

Hurricaner wrote:
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.

Most likely the control board sensed AC and switched to 240V. Now it's likely toast and maybe the heating element and wiring.

OP Other items to check: Any standby device like TVs and AV units. Also the ATS unit if equipped.

[Old-Biscuit]

OP......
What fridge brand/model?
Glass fuse on the circuit board will be for AC..but high voltage would not blow it....high amps does
High voltage WILL damage the circuit board

Do you have Lights on fridge upper panel...interior light?
DC Fuse on circuit board is the 'auto blade style fuse'


All electronics on the high voltage will be suspect until tested/
Converter would be damaged as would control board for A/C Unit so test those when you have 120V AC Power available to your 5th wheel

[cavie]

wa8yxm 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.

He plugged into a WELDER outlet. 3 wires HOT. HOT. Ground. 240 volts across the hots.. Use of an adapter would still leave him fried.

He did not plug into a welder outlet. Rv will not fit a welder. OP changed the welder outlet to an RV outlet not knowing the RV was not 240 volts. Read the whole thread please.

[cavie]

wa8yxm 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.

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.

They are different enough. They physically will not fit. Some body has to do just what the op did. Wired a 120 outlet to 240 volts.

[pianotuna]

Try the fridge on propane. If it works, then perhaps only the heating element burned out.

mxdad777 wrote:
I checked the glass fuse on the fridge circuit board and unfortunately the fuse is good. My guess is the circuit board is toast.

[wa8yxm]

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.

He plugged into a WELDER outlet. 3 wires HOT. HOT. Ground. 240 volts across the hots.. Use of an adapter would still leave him fried.

[wa8yxm]

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.

[2naEagle]

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.
RV Electric

[Hurricaner]

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

[mxdad777]

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. ;). 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...

[jkwilson]

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.

[cavie]

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.

[Acampingwewillg]

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! 🙂

[mxdad777]

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.