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Electricity? Never touch the stuff

L8173
Explorer
Explorer
I'm hiring an electrician to run a 50 amp line at my daughter's house for my RV. I only need 50amps because I have two A/C units. It's a 30' toy hauler. No W/D hookups. Everything is 110 (I believe). Having a difficult time telling the electrician exactly what I need, since I don't really know myself. My cord is a four post cord. What should he run?? He's saying 220, but I don't want to blow stuff up. ANY info on this basic question would be appreciated. I've just never been able to grasp the concept. Please use small words, lol.
54 REPLIES 54

Alan_Hepburn
Explorer
Explorer
12th Man Fan wrote:
Before you have this done make sure the electrician knows what you need. It is not a normal 220V circut it is two 110V.

There have been several posts with pictures on this issue. If you install the wrong one it can cause severe damage to you rig.


Oh geez - here we go again...
----------------------------------------------
Alan & Sandy Hepburn driving a 2007 Fleetwood Bounder 35E on a Workhorse chassis - Proud to be a Blue Star Family!
Good Sam Member #566004

MEXICOWANDERER
Explorer
Explorer
Pine-Tree diagram delta wound transformers can easily be replaced with WYE wound transformers. WYE transformers dominate in the Mexican electrical grids of which there are over four hundred. Very few interties. When a customer demands 3-phase service down here he assumes the cost of buying the transformer, setting power poles precisely to CFE specifications. Then to a CFE customer provided service drop. CFE will then wire down to wires sticking up out of a "mufa" the pipe leading to the breaker box.

I realize that most folks on this forum are more interested in gaining a "George Jetson" electric lifestyle than thinking about what a P.O.S. cooking on an electric stove can be.

But muse this...

A three-phase air conditioner would be so much more efficient, that for the same cost a 20,000 or 25,000 BTU unit would become a reality.

The military insists on 400 Hz systems both for theft resistance and a lot more punch to the pound for generation and end-use.

And if a licensed electrician puzzles over how to wire a 240 stove with neutral, he's a fraud. Run like hell.

I purchased a military-grade 12.5 Kw Kato 3-phase 60Hz single bearing gen head for a song. It demanded a special flywheel drive plate like a number 11 that did not exist in the KATO nor the Kubota inventory. So a professional machinist friend used a CNC end mill to manufacture a custom adapter plate.

I created a custom-built SCOTT CONNECTION with 2 transformers to change 3-phase to single phase 240.

I have encountered so-called professional electricians that couldn't count past ten without unzipping their pants.

John_Wayne
Explorer II
Explorer II
Just make sure you have a good EMS surge protector or you check the readings Old-Biscut posted BEFORE you plug in your RV. To make sure it was wired correctly. In fact it's a good idea to do this before you plug in any time.
John & Carol Life members
01 31'Sea View single slide, F53 V-10 with 134,000 miles and counting.
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God Bless

KF6HCH

Dutch_12078
Explorer
Explorer
2oldman wrote:
L8173 wrote:
Having a difficult time telling the electrician exactly what I need, since I don't really know myself
Doesn't your electrician have internet access? Anybody can look this up.


Just follow the markings on the NEMA 14-50 outlet...
Dutch
2001 GBM Landau 34' Class A
F53 chassis, Triton V10, TST TPMS
Bigfoot Automatic Leveling System
2011 Toyota RAV4 4WD/Remco pump
ReadyBrute Elite tow bar/Blue Ox baseplate

2oldman
Explorer
Explorer
L8173 wrote:
Having a difficult time telling the electrician exactly what I need, since I don't really know myself
Doesn't your electrician have internet access? Anybody can look this up.
"If I'm wearing long pants, I'm too far north" - 2oldman

red31
Explorer
Explorer
Your 120v outlets/appliances use just one hot wire for 120v. Some will be wired to one hot and others to the other hot. It is possible to have 240v by using both hots but your RV's breaker panel won't be wired to use both hots for any outlet/appliance.

CA_Traveler
Explorer III
Explorer III
3 phase for residential and CG's??? Yea right that will happen right after the US switches from 120V to 240V. The UK did that right with 220V and 50Hz.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland

Bob

time2roll
Explorer II
Explorer II
I wish 3-phase was more common. Motors start and run sooo much better.
BTW NEC allows a park with 3 phase to wire two of the lines to L1 & L2 and you still have 120v to neutral but 208v between the hots.

cougar28
Explorer
Explorer
STBRetired wrote:
cougar28 wrote:

That's what happening when when you plug a rv 50 amp using the dog bone into a rv 30 amp. To over current the neutral in that way you would have to be on a larger service and 120v breaker above 50amp.


Not quite. The 30A receptacle should be protected by a 30 breaker, which will prevent drawing more that 30A, thus not overloading the neutral, which should be designed for 30A.



Didn't say you would overload it on a 30 amp service.He was asking about tying the 2 line together on the same 120v service.I was saying that what the dog bone dose. Said "To over current the neutral in that way you would have to be on a larger service and 120v breaker above 50amp."
2002 F-250 SD CC 7.3PSD Auto. XLT Short Bed 4X4 Off-Rd.Pkg.Highland Green,Westin Sportsman Grille Guard (Black) RBW Li'l Rocker Slider ,Prodigy Control Towing Jayco Eagle HT 30.5 MLOK,Handy 5er tailgate

MEXICOWANDERER
Explorer
Explorer
Look at how much open space there is BETWEEN upper bumps and equally open space BETWEEN. No energy. Wasted space low efficiency

Take a look at this




This is called THREE PHASE

RV manufacturers and therefore RV PARKS have not discovered THREE PHASE yet. So there are no 3-phase power posts yet. Let's not get into how parks are wired yet.

3-phase motors like for your A/C are much smaller and less expensive. The same size cord can deliver twice the energy. But rigs would need 3 phase generators. The changeover to 3-phase would be a titanic amount of work. But worth it in the end. Yes, 3 phase systems can utilize a neutral. The RV weight and space savings would be staggering. And utterly incompatible with today's RV electrical.

MEXICOWANDERER
Explorer
Explorer
Yahhhhhhh, the fog thickens!!!

Look people....

There is such a thing as a sine wave. Got it?

When the FuLL sine wave is used it is 240 volts

Draw a horizontal line exactly 50% distance between the sine wave peaks.

That line is NEUTRAL. Connected to the neutral connection on your service drop transformer. Let's call the upper HALF of the sine wave L1 line 1ine one

Let's call the area below the neutral halfway mark L2 Line 2

Nothing in a rig is connected to the top and bottom bumpy lines

Everything is connected from L1 to the neutral OR (read it again) From the bottom half bumpy voltage to the straight neutral line in the center.

Because if you connect one wire from the bumpy top directly to the bumpy bottom and bypass the straight center neutral you'll get 240 volts. Smoke, misery, bankruptcy.



And
NEUTRAL IS NOT NOT NOT earth ground. Go out to your transformer and stare at the THIRD connection that runs from the transformer to your house. It is that line the straight one in the graph.

12th_Man_Fan
Explorer
Explorer
Boy, my stay at the Holiday Inn Express must have been a total waste.

Sorry for all the confusion. I guess I am the only one confused.
2014 GMC Duramax 4X4 DRW Crew

2015 DRV Tradition

STBRetired
Explorer
Explorer
cougar28 wrote:

That's what happening when when you plug a rv 50 amp using the dog bone into a rv 30 amp. To over current the neutral in that way you would have to be on a larger service and 120v breaker above 50amp.


Not quite. The 30A receptacle should be protected by a 30 breaker, which will prevent drawing more that 30A, thus not overloading the neutral, which should be designed for 30A.
1999 Newmar MACA 3796 F53 6.8L
2016 Ford Edge Sport
Roadmaster Sterling A/T with Brake Buddy Select

cougar28
Explorer
Explorer
philh wrote:
Two questions,
2. Other than the problem of hooking to a single phase circuit, why wouldn't the AC units be 2 phase? Wouldn't that be much more energy efficient?


No not any more efficient. Let say the a/c unit pulls 15 amps on 120v.That's a 15 amp draw on one line.
Now that same unit on 240v would pull 7.5amps. That a 7.5 amp draw on each one of the 2 hot line with a total of 15 amps.
2002 F-250 SD CC 7.3PSD Auto. XLT Short Bed 4X4 Off-Rd.Pkg.Highland Green,Westin Sportsman Grille Guard (Black) RBW Li'l Rocker Slider ,Prodigy Control Towing Jayco Eagle HT 30.5 MLOK,Handy 5er tailgate

time2roll
Explorer II
Explorer II
philh wrote:
Two questions,
1. I've heard of some wiring the same 120V phase to both sides. Wouldn't this drive twice as much current through neutral line?
2. Other than the problem of hooking to a single phase circuit, why wouldn't the AC units be 2 phase? Wouldn't that be much more energy efficient?

1 yes however probably wired on a single 50a breaker and the two hots tied together. 50 amp 120v service. BTW this is NOT to code.

2 the air is configured for 120 for periodic 30 amp service and to match the generator power.