What is the service voltage?

[Camperdude]

My 2021 eagle mlok has a 4 prong when connected to 50 A, so is the camper 240v when this is 50A? The box has a double throw so it makes me believe it is.

Reason I'm asking is my new home has a 220 welders outlet accessible.

Thanks!!

[craigav]

There is 240V potential with a RV 50A connection. However, it is not used as 240V and instead is used as two 120V legs. Your welder outlet may or may not work for you depending on if it has 4 wires running to it. A 240V welder likely doesn't need a neutral like your RV requires, and therefore the outlet may not have a neutral which means it wouldn't work for you. Even if there are 4 contacts in the plug, I would check it all with a meter and make sure you have a neutral and a ground along with two hots. ~CA

[Slippy]

Home 220 is generally not wired the same as RV 50 amp. If you are thinking of plugging in, have an electrician familiar with home RV connections look at it first, or you could blow the electrical system on your RV.

[Edutron]

Welding 220v outlets are wired slightly different than a 220v Rv outlet plug. Youtube is an easy reference. I had an electrician run 220v wires to an outlet in the back of my garage for a welder plugin, but decided to turn that into an RV outlet to have shore power while at home. Need to buy a different outlet (female) plug and wire it. Pretty easy.

[Kevin Cooper]

Originally Posted by Camperdude

My 2021 eagle mlok has a 4 prong when connected to 50 A, so is the camper 240v when this is 50A? The box has a double throw so it makes me believe it is.

Reason I'm asking is my new home has a 220 welders outlet accessible.

Thanks!!

You are getting some wild and some vague answers.
Residential services in the US are a 120/240 volt single phase 3 wire with ground.
That is exactly what a 50 amp receptacle supplies for your RV. No, it’s not two 120 volts that add together. It is 240 volts that is divided in half by connection of a neutral conductor in the center of all the windings.
You must check the welder outlet to see if it has 120 volts. Many DIY people install the same receptacle as the ones at the campgrounds are and even connect the neutral. So, from hot to hot is 240 volts, from either hot to neutral is 120 volts, and from either hot to ground is 120 volts. As Craig said, there is typically no 240 volt appliances in a RV. There are a very few exceptions.
So, if you find you have a neutral and get 120 volts, verify that you have a minimum #8 copper or better #6 copper branch circuit conductors and they are connected to a 50 amp 2 pole circuit breaker.
If not, let us know what you find.

[Tadsher]

The voltage is 2 120 volt legs off the 240 volt feed, Most RVs do not use the 50 amp 240 volt supply as 240 v0lts they split the voltage into 2 120 volt legs. See the example below.

[Rodney27405]

Originally Posted by Camperdude

My 2021 eagle mlok has a 4 prong when connected to 50 A, so is the camper 240v when this is 50A? The box has a double throw so it makes me believe it is.

Reason I'm asking is my new home has a 220 welders outlet accessible.

Thanks!!

You probably have something that looks like this currently installed. 240V Welders typically have two hots (120V each leg) and a ground. Your trailer needs a Neutral wire in order to work correctly so the cable feeding the outlet would need to be changed to 6/3 with ground and the correct, 4 wire outlet.

[Camperdude]

Testing the 3 prong outlet at the house yields 120 each side and 240 from one hot to the other. Looks like they tied the ground to the neutral. I have an adapter that goes from 3 prong to the outlet needed for my shore line. Testing it on the camper end of the shore line I get 120 each side.

Originally Posted by Kevin Cooper

You are getting some wild and some vague answers.
Residential services in the US are a 120/240 volt single phase 3 wire with ground.
That is exactly what a 50 amp receptacle supplies for your RV. No, it’s not two 120 volts that add together. It is 240 volts that is divided in half by connection of a neutral conductor in the center of all the windings.
You must check the welder outlet to see if it has 120 volts. Many DIY people install the same receptacle as the ones at the campgrounds are and even connect the neutral. So, from hot to hot is 240 volts, from either hot to neutral is 120 volts, and from either hot to ground is 120 volts. As Craig said, there is typically no 240 volt appliances in a RV. There are a very few exceptions.
So, if you find you have a neutral and get 120 volts, verify that you have a minimum #8 copper or better #6 copper branch circuit conductors and they are connected to a 50 amp 2 pole circuit breaker.
If not, let us know what you find.

[Learjet]

is the neutral wire properly sized? It must be 6awg or bigger for 50 amp service.

Using a undersized ground wire for a neutral can cause you to have high and low voltage and create a fire hazard.

[craigav]

Originally Posted by Camperdude

Testing the 3 prong outlet at the house yields 120 each side and 240 from one hot to the other. Looks like they tied the ground to the neutral. I have an adapter that goes from 3 prong to the outlet needed for my shore line. Testing it on the camper end of the shore line I get 120 each side.

It sounds as if you have two hots (L1 and L2) and a ground, is that correct? If so, don't use that for your RV.

More information: While there is always a neutral to ground bond at the service panel when properly installed as that is required by code and even without code that is required for any level of safety for every outlet that the panel's breakers feed into (the main breaker panel neutral to ground bond). The ground wire itself (which is what exists on a 3 wire 240v outlet) should never carry any current and is often not even sized large enough to do so (the ground is undersized with the understanding that a proper connection would trip the breaker if there was a short to ground, therefore the ground wouldn't carry current except for a moment or two which is why it is often undersized). Point being, even though you are measuring 120v to ground (x2), that is to be expected but the outlet should not be used for your RV unless it has 2 hots, 1 Neutral, and 1 Ground. The risks are very high to do otherwise, not just to the RV, but to the wiring in the house, fire potential, and an electrocution hazard. ~CA

[Kevin Cooper]

Originally Posted by Camperdude

Testing the 3 prong outlet at the house yields 120 each side and 240 from one hot to the other. Looks like they tied the ground to the neutral. I have an adapter that goes from 3 prong to the outlet needed for my shore line. Testing it on the camper end of the shore line I get 120 each side.

Craig is absolutely correct! A three prong has only ground, not neutral. The smaller, probably bare “equipment ground” is not supposed to be a current carrying conductor. If you insist on using it as is, will it work? It will seem to be working, but in reality, as Craig said, you will be putting anyone that comes in contact with that RV at risk of shock and yes possibly electrocution, (that means death). Also, since it was mentioned that the ground is smaller, and bare, if enough amps are flowing, that bare conductor in your RV will be getting very hot. So hot, that it can cause a fire before it shorts out to the hot because it melted the insulation. If you are still not convinced, let us know.
Always practice safety! The life you save may just be your own!

[Tadsher]

Originally Posted by craigav

It sounds as if you have two hots (L1 and L2) and a ground, is that correct? If so, don't use that for your RV.

More information: While there is always a neutral to ground bond at the service panel when properly installed as that is required by code and even without code that is required for any level of safety for every outlet that the panel's breakers feed into (the main breaker panel neutral to ground bond). The ground wire itself (which is what exists on a 3 wire 240v outlet) should never carry any current and is often not even sized large enough to do so (the ground is undersized with the understanding that a proper connection would trip the breaker if there was a short to ground, therefore the ground wouldn't carry current except for a moment or two which is why it is often undersized). Point being, even though you are measuring 120v to ground (x2), that is to be expected but the outlet should not be used for your RV unless it has 2 hots, 1 Neutral, and 1 Ground. The risks are very high to do otherwise, not just to the RV, but to the wiring in the house, fire potential, and an electrocution hazard. ~CA

Agree 100% what craigav and Kevin Cooper said

[Camperdude]

Originally Posted by Tadsher

Agree 100% what craigav and Kevin Cooper said

I'm going to run a ground wire from the box to the outlet and put a 4 prong plug in. Figured might as well do it right.

[Kevin Cooper]

Originally Posted by Camperdude

I'm going to run a ground wire from the box to the outlet and put a 4 prong plug in. Figured might as well do it right.

You need to run a white neutral that is the same size as the hot conductors. You already have a ground.

[Learjet]

Originally Posted by Kevin Cooper

You need to run a white neutral that is the same size as the hot conductors. You already have a ground.

Like I said above ^^^^^^^^^^^

[Kevin Cooper]

I’ve seen videos of people running #10 copper on 30 amp breakers to a 50a receptacle for a small wire feed welder.

[Camperdude]

Originally Posted by Kevin Cooper

Craig is absolutely correct! A three prong has only ground, not neutral. The smaller, probably bare “equipment ground” is not supposed to be a current carrying conductor. If you insist on using it as is, will it work? It will seem to be working, but in reality, as Craig said, you will be putting anyone that comes in contact with that RV at risk of shock and yes possibly electrocution, (that means death). Also, since it was mentioned that the ground is smaller, and bare, if enough amps are flowing, that bare conductor in your RV will be getting very hot. So hot, that it can cause a fire before it shorts out to the hot because it melted the insulation. If you are still not convinced, let us know.
Always practice safety! The life you save may just be your own!

I noticed the camper outlet is only 3 prong. Does this mean they tired the neutral and ground together?

It's 4 prong to the power but only three prong at the camper.

[Grumpy]

Originally Posted by Camperdude

I noticed the camper outlet is only 3 prong. Does this mean they tired the neutral and ground together?

It's 4 prong to the power but only three prong at the camper.

Which is 4 the outlet or the cord? Which is 3?

[Kevin Cooper]

Originally Posted by Camperdude

I noticed the camper outlet is only 3 prong. Does this mean they tired the neutral and ground together?

It's 4 prong to the power but only three prong at the camper.

Ok, let’s start all over. If you open the door on your electrical panel, what is the amps of the largest breaker in the panel? 30 amp or 50 amp.
You comments are contradicting each other.

[Learjet]

Probably sees the three twist lock connectors and doesn't see the outside ground terminal on the twist lock connector.