50 amp service

i have Monaco Riptide that is 50 amp. I'm going to a dog show and we are staying at the horse farm that has 30 amp service. If i plug my RV in will it work on 30 amp with conversion plug of course

    Ours does.

Ed

It will work if the 30A is 30A @ 120v and not a 30A dryer or welder outlet. Those are 240v and will destroy your Rvs electrical system if you hook to them. Unfortunately, the pin configuration of those 240v outlets are close enough that an RV 30A plug can be made to fit - and cause a disaster.

Note however, that 30A is 30A, but 50A is actually 2 x 50 = 100 amps total. Ergo you have much less power available when adapted down to 30A. To put it in simple terms, you can't run all your stuff at once without tripping the breaker on the 30A supply.

If your RV has an Energy Management System, it will automatically prevent you from exceeding 30A at any one time, i.e. it will shut down some circuits (called load shedding) before the breaker can trip. Many 50A Rvs have an EMS.

thank you for answering

Echoing what Gary said:

There are many and I mean FAR TOO MANY threads in this and other forums from folks who plugged into a dryer or welder or air compressor or other 220 volt outlet.

The rule I have is this: IF plugging in at a location OTHER than a campground.
MEASURE THE VOLTAGE FIRST.

I have "excepted" that rule just one time.. It was at a Moose Lodge,,, The Governor ask if I'd tried the 30 amp outlet,, (I did not even known there was one) I had, however seen the circuit breaker box, and found the ganged 220 volt breakers feeding it so I already knew, without measuring, that I did NOT want to plug in there.

thanks for the info...and leading me here TOM!  Since no one was home here, I DID bring out my DVM and measured the 240Volts.  Even though my sister in law, bless her soul said we could hook into the 30amp circuit. 
I used an adapter to plug into a regular 15amp 110v to limp along for the present.
Since everyone is SO helpful, WHY then can't they make a reducer that can convert the 220 to 110?
thanks!!
lesley

Since everyone is SO helpful, WHY then can't they make a reducer that can convert the 220 to 110?

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They do - it's called a transformer and it's big, heavy and expensive.

All of the circuits you'll plug into are 120 volts - like water in a pipe,  there's 120 volts of pressure trying to push electrons down the wire.  15 amps, 20 amps, 30 amps, etc. specifies the size of the pipe - how many electrons it can deliver.  If you're plugged into a 30 amp circuit, you can draw up to 30 amps, you aren't drawing 30 amps from it all the time.  But the voltage (available pressure) is always 120 volts.

And, with that so-called 50 amp service, even though you did measure 240V across the power leads, the manner in which that is wired in the trailer/motor home is 2 legs of 120 volts each. NOTHING is connected across 240 volts in the normal sense, (like your clothes dryer or stove at home is). Hence, the warnings posted above about welder outlets etc.

There are simple cord adapters available to connect a 50 amp service post to a 30 amp machine and others to connect a 30 amp service post to a 50 amp machine safely.... BUT there is no free lunch here, you are limited to 30 amps maximum in either case.

In a straight 50 amp connection you have two legs of 120V/ 50 amps each for a total of 100 amps at 120V available.

Alfa38User said:

And, with that so-called 50 amp service, even though you did measure 240V across the power leads, the manner in which that is wired in the trailer/motor home is 2 legs of 120 volts each. NOTHING is connected across 240 volts in the normal sense, (like your clothes dryer or stove at home is). Hence, the warnings posted above about welder outlets etc.

There are simple cord adapters available to connect a 50 amp service post to a 30 amp machine and others to connect a 30 amp service post to a 50 amp machine safely.... BUT there is no free lunch here, you are limited to 30 amps maximum in either case.

In a straight 50 amp connection you have two legs of 120V/ 50 amps each for a total of 100 amps at 120V available.

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That clears it up.  50A is from a 50A 240VAC or two pole breaker and 30A is from a 120 single pole breaker.

kenb1023 said:

That clears it up.  50A is from a 50A 240VAC or two pole breaker and 30A is from a 120 single pole breaker.

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But you still can't safely plug a 50 amp RV into a 240 volt AC outlet intended for another use.  The reason is all of the RV's loads are 120 volts, and depend on a strong neutral conductor to keep the two 120 volt circuits isolated from each other.

Without a strong neutral line, the 240 volts will divide unequally between the two 120 volt circuits, putting too much voltage on one side and not enough on the other.

Stoves, dryers, etc. use 240 volts for the majority of their load, so the neutral conductor in these circuits may be too small for RV use or nonexistant.

The other plug that blows up RVs is the 240 volt, 30 amp "welder" outlet.  It's identical in size and overall shape to the 120 volt RV outlet, the only difference is the shape of the grounding pin - a half circle for the 120 volt RV plug, L-shaped for the 240 volt version.

If you really try, you can force the RV plug into the 240 volt socket despite the different ground pin shape.

You got it, Now the popular dogbone adapters that let a 30 amp RV plug into a 50 amp circuit.. Can you figure out how they work?  If not read on

There are two types  To convert just re-number the two Legs (L1 and L2) in the reverse order

50 amp 30
L-1 --- hot
Neutral same
L-2  not connected
Safety ground (Same)

IT is that simple. If you are easily confused stop reading now

50 amp, like the service to your house, is called 120/240 volt because hooked as above you get 120

L-1 to L-2 (Across the plug) ios 240


As Lou said though, do not make your own adapter for a dryer or welder outlet,  Fire Departments still make house calls don't you know.

Lou Schneider said:

But you still can't safely plug a 50 amp RV into a 240 volt AC outlet intended for another use.  The reason is all of the RV's loads are 120 volts, and depend on a strong neutral conductor to keep the two 120 volt circuits isolated from each other.

Without a strong neutral line, the 240 volts will divide unequally between the two 120 volt circuits, putting too much voltage on one side and not enough on the other.

Stoves, dryers, etc. use 240 volts for the majority of their load, so the neutral conductor in these circuits may be too small for RV use or nonexistant.

The other plug that blows up RVs is the 240 volt, 30 amp "welder" outlet.  It's identical in size and overall shape to the 120 volt RV outlet, the only difference is the shape of the grounding pin - a half circle for the 120 volt RV plug, L-shaped for the 240 volt version.

If you really try, you can force the RV plug into the 240 volt socket despite the different ground pin shape.

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Most codes now call for any 240 circuit to have two hots and one neutral and a separate ground.  The Neutral needs to be at least on size smaller than the hots (Same size is recommended) same goes for the ground.  In my area the ground can be two sizes smaller.  so for a 50 amp circuit you need at  a minimum two 6 AWG leads for the hot, one 8 AWG for the neutral and a non-insulated 10 or 8 AWG ground.  If you use Romex style cable that is how they come already. 

Now do not take this as gospel, refer to your local building codes any time you mess with the electrical.  If in any doubt, get a licensed electrician. 

I have actually been at a RV Park ONE TIME that had 50 amp service that was not 240 volt, but 120 volt. Same phase on both hot lines. Our EMS limited us to 30 amp, 120 volt, because it could not see 240 volt. I carry a 2 leg, 30 to 50 adapter, so we can hook up to two 30 amp services (as long as they are different phases) to trick the EMS into letting us run more than 30 amp 120 volt. Even though it is not the full 100 amps, at least I can get 60 amp this way. It helps a lot.

Household electricity works like this:

The electrical supply that feeds into your main breaker panel has (should have, if new) 4 wires:  2 hots, a "neutral", and a grounding conductor.

First let me say that there is some confusion with the last 2, since the "neutral" is actually called the "grounded conductor" now, and the groundING is called the equipment grounding conductor, or ECG.  The difference is that the ECG is not supposed to carry any current (except in a fault/short/electrical leak, etc.) while the groundED conductor (neutral) DOES carry current.  So I'll use the terms Neutral and ECG for these two.  Also, with systems using conduit and some BX, the conduit as used as a grounding conductor.

Back to it now-

The 2 hots and the neutral entering the breaker panel are what I'll focus on here.  Consider the "neutral" wire to be zero volts.  One of the hot wires will be +120V relative to the neutral, and the other hot will be -120V.

Put a volt meter across the 2 hot wires and you will get 240V.

Many 240V appliances only use the 2 hot wires to supply the 240V that they need.  The neutral wire is redundant.  One hot leg is "pushing" electrons in while the other hot leg is "pulling" and they switch directions, or alternate, 60 times each second or 60 Hertz.  That's where you get 240V AC @ 60 Hz.


So a 50A RV receptacle is still wired as a 240V, but differently than a household 240V circuit.  The household circuit is using both hots at the same  time and not using the neutral to give 240V.  The RV receptacle uses the 2 hots individually, each with the neutral to complete two 120V circuits.  Since the hots are out of phase with each other, the current carried by the neutral conductor will be the difference of the current carried by the 2 hots.  For example, if each hot is carrying, say, 12A, then the load on the neutral will be zero.  That's why it is called the neutral.  If one hot is carrying 12A and the other is carrying 10A, there will only be 2A going through the neutral.

Probably too much information here, but I hope it's helpful.

Lou Schneider said:

They do - it's called a transformer and it's big, heavy and expensive.

All of the circuits you'll plug into are 120 volts - like water in a pipe,  there's 120 volts of pressure trying to push electrons down the wire.  15 amps, 20 amps, 30 amps, etc. specifies the size of the pipe - how many electrons it can deliver.  If you're plugged into a 30 amp circuit, you can draw up to 30 amps, you aren't drawing 30 amps from it all the time.  But the voltage (available pressure) is always 120 volts.

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How BIG/Heavy/and Expensive is a transformer?  If I could plug a transformer into the 220v welder outlet and leave it in their garage....I would be able to plug into it whenever I visit up here.  Right now i am on the 110v/15A circuit so I cannot use the A/C or appliances in my motorhome.
thanks!

If I could plug a transformer into the 220v welder outlet and leave it in their garage.

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Many people have found the folly in doing that kind of thing including some "professional electricians"...$$$$ . It would be much better to simply add a 50 or 30 amp properly wired  RV connection and leave it at that 

kiheilesley said:

I used an adapter to plug into a regular 15amp 110v to limp along for the present.

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If you are adapting down from 50 amp it's a big no-no in my book. I burned out a power supply trying to power a 50 amp motorhome that way. It's a 30 amp adaptor or nothing for us now.

I'm not sure that is what killed your Converter.. Less there was more running than the converter.

I have a few spots I park where all I can get is 15/20 amps.. On those occasions I pull the plug on my converter and plug JUST IT in, nothing else, the other 120 volt devices in the Motor Home either run on inverter (Televisions/radios etc) a different 15/20 outlet (A/C or one heater) or the generator (microwave and kitchen appliances drawing serious wattage)  The coffee maker runs on the inverter.. Or the toaster, (Even the microwave for short periods)

Fridge gets locked on Gas or left on gas/auto Water heater is OFF (no power to it anyway) (The fridge can be switched between Inverter and non-inverter lines.  This is because the outlets in the bedroom are on the same feed and those keep my cell phone and sometimes this computer happy).

I have actually been at a RV Park ONE TIME that had 50 amp service that was not 240 volt, but 120 volt. Same phase on both hot lines. Our EMS limited us to 30 amp, 120 volt, because it could not see 240 volt. I carry a 2 leg, 30 to 50 adapter, so we can hook up to two 30 amp services (as long as they are different phases) to trick the EMS into letting us run more than 30 amp 120 volt. Even though it is not the full 100 amps, at least I can get 60 amp this way. It helps a lot.

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I installed a switch on my EMS to override the 240v check so I can run from a pair of in-phase outlets, whether dual 30, dual 20, or a 30-15 pair. There is nothing magic about it - the Intelletec EMS does that itself if it detects the generator running (the popular Onan 7500/8000 is also a dual, in-phase power source). There is a +12v signal line that tells the EMS to skip the 30A limit management.

If the 3-pin welder outlet is no longer needed as a 240v source, it can be converted to 120v quite easily by changing one of the hot wires to be a neutral and installing a 30A RV-style outlet in the outlet box.

Assuming the existing outlet is designed for a welder, the problem is that it has no neutral. It has only two hots, each 180 degrees out of phase with each other. I don't think a transformer can fix that, but will yield to Lou Schneifer's superior knowledge if he thinks it can be done.  You can pick up a 240/120v transformer that will handle 3000-4000 watts on ebay for around $100-$200. That's maybe 20% of the list price for such a device, so a heck of a bargain.