50A Service At Home

Houndie Dog · 09-28-2010, 01:54 PM

Hello,
Could someone please help me with an electrical question ?
I just purchased (ordered) a Cougar 326MKS fifth wheel and would like to add a 50A service outlet to my garage so I can plug my trailer in.
I have read the forums and articles on the internet that state that I need a 50A outlet with 2 120VAC prongs and a ground and neutral. I talked to two different RV service departments and they both said that is wrong, they stated that I need only one prong with 120VAC and a ground and neutral.....And one prong gets nothing.
So.....looking at the drawing, X gets a 120VAC wire, Y gets a 120VAC wire, U gets the ground wire, and W gets the neutral wire ??????????????

I have an electrician coming in 2 days and still can't figure out what to tell him to do.
Thanks,
Grant

geo · 09-28-2010, 02:55 PM

The way I understand it, and please someone correct me if I am wrong, is that the trailer 50 amp service and your home/residence share this type of service in common. What I mean is that you have 240V coming in to your house - and probably 100 amp service (more later on this). One side or end of your house or trailer is wired between the X and W wires of the NEMA 14-50R receptical your attached as a jpg. This means you are getting a 120V "30 amp" service in an alternating current that goes along a sine curve as postive-negative-positive. The other side of your house or trailer is wired between the Y and W of the NEMA 14-50R receptical. This means you are getting a 120V "30 amp" service in an alternating current that goes along a sine curve as negative-positive-negative. To get 240V service say for a clothes dryer, you would wire between the X and Y since they are sine curves out of phase by 180 degrees and the potential between them is 240V. (Still with me here?)

So, you probably already have a receptical in your home that would give 50 amp service to your Cougar - behind your clothes dryer! However, you need to look at the electrical breaker panel in your home. For one, it's probably a 100 amp panel. Find the breakers for the dryer - there will be a pair of breakers that are latched together. Are their value 25 amp each or maybe 30 amp each? If so, there is the 50 amp service. But here's the catch, the power line and meter that are coming in to your house are probably rated for 100 amp service (older homes) or maybe 200 amp service. You will probably have to ask the utility company on that.

So, if you cross-wired something between the ends of your home or the ends of your trailer, and that something was rated at 120V, you would plug 240V across it, or basically short the two hot leads together. KABOOM! (Please DO NOT DO THIS!) That's also why you have two rows of breakers on the electrical panel. The 240V wires come in and split between the two banks of breakers, so you have 120V on a side. The special breakers, like the dryer breaker, attaches in to a special spot that puts those breakers across the two 120V lines.

So, when the electrician comes out, first thing he will have to determine is if your present breaker box can handle an additional 50 amp load. If not, he will have to put a drop in from the meter if you have enough ampere service from the utility to the meter.

As a side note, about the 30 amp - 50 amp plug converter you use when you only get 30 amp service. These are the old 240V service many of us grew up with in the '50s. Yes, there is 240V between the two hot wires and the neutral is both common and ground - in other words a floating ground! Not the safest circuit in the hopper. These two hot wires have 15 amp breakers on each of them.

So, good luck with the electrician. He will probably know exactly what to do. However, get ready for a little higher invoice if he has to get into the meter for another drop. You might want to call the utility company to find out what your service is before the electrician gets there.

If what the RV service departments are telling you would be correct, then you would need one 120V line with a 50 amp breaker on it! Yikes! I know from my own experience that Keystone put both the A/C units on my Alpine on the same side of the "circuit". Luckily the dealer caught that when they installed a generator, and changed the front A/C to the other side of the "circuit".

If you have a voltmeter, you could actually test this out at your local campground, if you know what you are doing and can steady up to stick the probes into the outlet.

Ron

**hankpage** · 09-28-2010, 03:43 PM

Grant, Ron gave a good explanation of what you need. If you need any more go to http://www.dasplace.net/RVWiring/wiring.html to further explain. Note the part to be sure your electrician knows it is for RV use, as RV appliances are 120v.(exception .. high-end coaches) and not 220v like household and will cause an unbalanced load. Good luck and I'm sure a licensed electrician will know what to do, Hank

therink · 09-28-2010, 05:05 PM

Hi, I also have 50 amp in my rig. I installed a 30 amp outlet in my yard and runs everything fine. I thought about running 50 but figured it was more trouble than worth. Everything I needed for 30 amp, I found at Lowes.

Houndie Dog · 09-28-2010, 05:07 PM

Thanks for the responses, that gives me somewhere to start

Jim W · 09-29-2010, 04:21 AM

Grant, I agree with everything that was said here to you above. I also have a question on your model of camper for you. That is do you have two A/C units and if you do will you run them both together?

The reason I ask this, is with my model of camper everything but the second A/C unit is wired so I can use a 30 AMP circuit. The second A/C unit (if I had one) would be wired to the other side of the circuit panel. Thus requiring the 50 AMP service.

I plug my camper into the 20AMP service I have in the garage with a adapter plug. I can operate everything in the camper on this circuit except the A/C unit. I have never had an issue operating the TV or anything else in the camper.

Jim

09-29-2010, 11:04 AM

You don't need 50 amp service for storage purposes or even occassional use at the home. 30 amp service should be sufficient and cost a little less. For instance, at my camp, I only installed a 30 amp plug and it runs everything, including two a/c's. The breakers are cheaper, the extension cords are cheaper, the plugs are cheaper, etc.

Houndie Dog · 09-29-2010, 02:08 PM

The answer regarding the AC's is - yes, I have 2 AC's. Since I am new to this RV stuff I ASSUMED that I needed 50A service because the unit was 50A. I will normally only have the RV at home the night before we go somewhere to get the fridge up and running, or when doing routine maintenance so I guess I really don't need to run both AC's anyway.
I now think the way to go is 30A and I just won't run the AC in the bedroom (if it's hot out). That will give me alot more options as far as the work and cost involved in getting power outside.

Thanks for everyones help and responses.........

16 more days until I get my trailer yippee.............

kenn209 · 09-29-2010, 04:19 PM

I keep ours plugged in 24/7 and I use an orange extension cord plugged into the outlet in the garage. Has worked since we have owned our first camper back in 06, We only plug it in to keep the fridge cold and the battery charged. I did run the A/C fan at one time, didn't trip any breakers in the house. I hope this isn't hurting anything? I think its a 20AMP circuit...

Ruffus · 09-29-2010, 05:23 PM

Just a note. My DW and I been fulltiming for a couple months now. The last two weeks we have been sitting in my father-in-laws front yard plugged into his shop power which is only a 20 amp service with my 50 amp shore power cord (30 feet) and a 25 foot 110 extension cord. We've ran the A/C, microwave and ceiling fan and have had no problems. These new units pull a lot less juice than you think. The new A/C's are a lot better than the old compressor type. Just food for thought.
Jim B.

Houndie Dog · 09-29-2010, 05:46 PM

I went out and bought a 30A RV box that is weatherproof. My electrician will be over tomorrow and at least I can tell him what I want now.

By the time I get my trailer I will definatley need to take it somewhere and relax :-)

Thanks everyone

**hankpage** · 09-29-2010, 06:28 PM

There's always "Driveway Camping". It's a good way to get used to a new trailer and help figure what you really need when away from home. I have 30amp service and cable to mine, so when the DW can't find me she knows where to look. Enjoy your new trailer, Hank

Seann · 09-30-2010, 09:53 AM

Quote:

Originally Posted by Houndie Dog

The answer regarding the AC's is - yes, I have 2 AC's. Since I am new to this RV stuff I ASSUMED that I needed 50A service because the unit was 50A. I will normally only have the RV at home the night before we go somewhere to get the fridge up and running, or when doing routine maintenance so I guess I really don't need to run both AC's anyway.
I now think the way to go is 30A and I just won't run the AC in the bedroom (if it's hot out). That will give me alot more options as far as the work and cost involved in getting power outside.

Thanks for everyones help and responses.........

16 more days until I get my trailer yippee.............

IF you are not going to run the A/C units you can actually get away with just adding adapter plugs and plugging your RV into a conventional outlet. 15A This will save you a ton of $$$

Houndie Dog · 09-30-2010, 04:02 PM

OK, I now have a 30A, 120VAC, 60Hz RV outlet attached to my garage. I did it myself and it didn't even smoke when I flipped the breaker

All I need now is a trailer to plug into it

Good idea about the driveway camping, I think I will try that out before going anywhere.

Thanks again,
Grant

bigbluejmc · 03-18-2012, 01:43 PM

Hi.

The 327RES came with a 50 amp cord. I like to build a 30 amp extension cord to plug the unit at home. I'm just not clear on how to wire the female 50 amp sucket.

Any help (drawing would be great) is appreciated...Thanks

charltons · 03-19-2012, 05:31 PM

Quote:

Originally Posted by Seann

IF you are not going to run the A/C units you can actually get away with just adding adapter plugs and plugging your RV into a conventional outlet. 15A This will save you a ton of $$$

So true, my electrician basically told me the same thing. I have 400amp service at home so no worries on not enough power. I did however have put in a dedicated 110v outside outlet and I use this for keeping my TT plugged in. Great for running dryers in the winter and poering up the fridge before trips. Cost me about 10.00 in parts.

geo · 03-20-2012, 05:07 AM

Quote:

Originally Posted by bigbluejmc

Hi.

The 327RES came with a 50 amp cord. I like to build a 30 amp extension cord to plug the unit at home. I'm just not clear on how to wire the female 50 amp sucket.

Any help (drawing would be great) is appreciated...Thanks

Bigbluejmc -

Don't wire a female 30 amp, just head off to CW or WalMart and buy a "30 to 50" amp converter pigtail. You will want one in the future anyway. You will probably find that you will want a 50 amp extension at some time. Overall, 50 amp extension and 30-50 pigtail will be cheaper

For more info, go to the link in my earlier message from long ago. But in that message I wrote, there's some corrections I need to make about 30 amp service. The link is good though.

Ron

christopherglenn · 03-20-2012, 10:15 AM

Dealer is full of it. The 50 amp 4 prong connector is 50 amp 240 volt with neutral.
Look in your breaker box in the trailer, you should see 1 or 2 50 amp brakers (usually in the middle). If you have one, you need 1 50 amp 120 volt leg. I would bet you have 2 50 amp brakers. If you only wire one hot leg and leave the other disconnected 1/2 your trailer will be without power. If the converter is on the side without, you will be in the dark FAST.

byrdr1 · 03-20-2012, 11:57 AM

I have had a 30A RV plug at my house since the popup days. When we bought this camper with 50A service. I used a dog bone 30a male plug to 50a female plug and used the big ole' heavy 50a cord that came with the camper for a few months. I priced a new 50a cord, very expense. Figured if I could find a Marinco 50a to 30a cord I would be good to go. Plus if someone comes by the house and steals the 30a 25ft RV cord easier to replace than the 50A 25footer plus cheaper. Then over the winter months I shopped around to find what I was looking for. Amazon had just what I needed and it was around $85 (PRICE has gone up)shipped to the house. I use it all the time at the house now and keep the
50A cord locked up inside the 5er. Another mod? I did.
I have used the 30a cord once at a campground. the rest of the time I use the 50a cord.
ParkPower-Marinco-124ARV-25-Electrical-Receptacle(50-amp 125/250-Volt Receptacle with 30-Amp 125-Volt RV Straight Blade Plug, 25-Feet)

geo · 03-20-2012, 12:32 PM

Actually, the 50 amp service is two 120VAC hot leads (red and black wire) with 50 amps EACH. Note at the campground you will find two 50 amp breakers (hopefully) to shut off to plug in. As each of these hot leads carry 120V alternating current, they are synchronized to be exactly opposite of each other. Thus if one connected an appliance with these leads, like a clothes dryer or home a/c, you have better make sure it is rated for 240VAC!

When these power leads enter the breaker box/power panel of the RV, they are separated. If your RV is rated at 50 amp, then you have two 50 amp master circuit breakers - one on the red and one on the black wire. Neutral white services both. One side of the power panel uses 50 amp power from the red power input and the other side of the power panel uses 50 amp power from the black power input. You might say one side of the RV has a + sine wave AC and the other side has a - sine wave AC!

So, each power leg is rated at 50 amps separately.

If you have 30 amp power, then the three pronged plug has one hot (black) wire, one neutral (white) wire and a ground (green) on one 30 amp breaker. This means that your power panel has one 30 amp breaker and the whole RV is running only one one hot power (wire) input lead. No opposing sine waves here.

So, what happens when you plug a 50 amp plug into a 30 amp receptical with a pigtail or dog-bone adapter? The 30 amp power is connected to both hot leads of the 50 amp plug. This doesn't mean you have 30 amps each nor does it mean that you have 15 amps each - you have 30 amps total. Your 50 amp breakers in the power panel are worthless since the outside 30 amp breaker will trip before either one of them will.

I am not aware of any RVs that have a power panel with only one 50 amp breaker. Doesn't mean there might not be some out there, just never seen one. Your home works much the same way. The power coming into your home is probably 100 amp service. If you look at your circuit breaker or fuse box, you will see two rows of breakers/fuses. One side is using one hot leg of the 240 VAC service (black wire) and the other side is using the other hot leg of the 240VAC service (red wire). Each wire separately gives only 120VAC when measured to the white wire (neutral).

What it boils down to is this: If you understand the above and are going "yeah, yeah, yadda, yadda", then you are probably OK and might even be inclinded to correct my mistakes. If the above sounds like a mess of gobbly-goop, better hire an electrician! Actually, always hiring an electrician is probably a better idea!

Ron

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