Community Forums

Sundog · 06-10-2008, 09:41 AM

Thank you to everyone. We are scheduled to leave for home tomorrow. Once there I can plug into a 30 amp circuit that I know is good. This PM I am going to transfer back to the 50 amp service to see if I can replicate the previous problems and then when I get home we hae a reputable service dealer about 3 miles away. I'll take this rig in for a check-up.

Thanx again to all.

Spikester · 06-10-2008, 09:43 AM

You can also use your voltmeter to check the 50 Amp plug on the pedestal, here is what you should see if it is okay:

You should measure 125V from either vertical blade (check them both) on the side of the socket to either the neutral slot on the bottom or the ground contact on the top as well as to the box the socket is mounted in if it is a metal box. You should measure 250V from one side blade to the other side blade.

Hope this helps!

Spike

imgoin4it · 06-10-2008, 11:21 AM

I found at least two occasions where the RV park had rewired the power pedistal for a 50 amp plug. Not 50 AMP POWER, JUST 50 AMP PLUG. At one I told them I only had 30 amps and asked if I could move to the empty spot next to me. They said if I wanted 50 amps I would have to move to another section in the park. (which I did) Another park had a bunch of spots thay called 50 amp and all of them had 50 amp recepticals, but each had a sticker on it that said only "30 amps available". I'll bet as others have said -you have only one 110v leg which means 30 amps not 50.

Joe Gilbert · 06-10-2008, 02:44 PM

Bruce W: I'm not sure we really want to go over this phase thing again but the power to our RV's, be it 20A, 30A, or 50A is single phase. The two voltages feeding the 50A circuit are in phase, derived from a center taped transformer. Having said that is is correct that for the 50A circuit you will read typ 115V on either leg or typ 230V between the two hot legs.

M&EM · 06-10-2008, 03:27 PM

Not quite. I believe 2 voltages derived about a center tap transformer configuration would be 180 degrees out of phase

"007" · 06-10-2008, 04:59 PM

SunDog do you have a surge protector in your coach. If you have should show up any problems with pedestal power. If not be careful with changing your shore power around. If you have a long cord try another ped as someone surggested.

Renipladlo · 06-10-2008, 07:16 PM

http://www.bobhatch.com/electricStuff/30to50amp.htm

This gentleman seems to know his electricity. Read all about it here, including some interesting information about his moving his MH to 50 amps instead of the 30 he used to have.

Great site.

Joe Gilbert · 06-11-2008, 10:42 AM

Yes! Renipladlo. I may not the brightest bulb on the tree but I am correct about this being single phase. I am a master electrician, not that that always makes me correct. It is not a big deal to us average Rv'ers but technically the two legs are single phase.

Where is Lug Nut when I need him. I think he know all this stuff.

RustyJC · 06-11-2008, 11:22 AM

The supply to the center tapped transformer in 50 amp service is indeed single phase, but the fact that the center tap is neutral means that L1-N will be 180 degrees out of phase from L2-N. If these were in phase, L1-L2 would read 0v instead of 240V and neutral leg currents would be additive which could put as much as 100 amps on the neutral of the shore power cord.

See HERE.

Rusty

M&EM · 06-11-2008, 11:33 AM

Joe, technically the two legs and the neutral (centertap) are called split phase among other names. Check it out here:

http://en.wikipedia.org/wiki/Split_phase

Joe Gilbert · 06-11-2008, 03:36 PM

I promise rhis is my last word on this. Those of us with a 50A RV service at our home know that this is feed directly from our residential
home power panel. This is single phase (ask your power company). You might call it split-phase but the power company does not.

A split phase electricity distribution system is a 3-wire single-phase distribution system, commonly used in North America for single-family residential and light commercial (up to about 100 kVA) applications. It is the AC equivalent of the original Edison 3-wire direct current system. Its primary advantage is that it saves conductor material over a single ended single phase system while only requiring single phase on the supply side of the distribution transformer.[1] Since there are two live conductors in the system, it is sometimes incorrectly referred to as "two phase".

Let's let this die a natural death.

RustyJC · 06-11-2008, 03:47 PM

The critical factor in RV 50 amp service is that the two hot legs are 180 degrees out of phase with respect to neutral and will read 240 VAC across L1-L2. If the park pedestal is miswired such that the voltage from L1 to L2 is in phase (i.e., L1 to L2 reads 0 VAC), then there is a severe risk of overloading the neutral conductor in the shore power cord.

Letting it die a natural death is fine - as long as no one misunderstands the post to read that the 2 hot conductors should be in phase with each other with respect to neutral. They should not be.

Rusty

Nonno · 08-08-2008, 03:17 PM

If I may, one last gasping breath please. I'm having an electrician install a 50A service at my home for the RV. Do I need to be sure he is aware of the "critical factor in RV 50A" or is this a given when I ask him for 50A?
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The critical factor in RV 50 amp service is that the two hot legs are 180 degrees out of phase with respect to neutral and will read 240 VAC across L1-L2. </div></BLOCKQUOTE>

Route 66 · 08-08-2008, 04:14 PM

CLICK ON THIS LINK.

It's all explained there.

Also there is a page you can print out and give to the electrician.

There is nothing tricky about 50 amp service. It's all basic and straight forward electrical work.

I put my own 50 amp service in with no problems.