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jacwjames · 10-04-2020, 09:53 AM

Thanks for the clarification but cavie said, it still has me wondering, but I have other things to worry about so all is good.

Solo_RV_Guy · 10-04-2020, 10:34 AM

Quote:

Originally Posted by hohenwald48

Good luck getting folks to understand that. I gave up trying years ago. [emoji849]

I suppose it's possible the installer put both branch circuit hot wires on the same breaker.

Dont get me started on "phase." Okay, too late... for those at home (Hohenwald and Cavie and Twinboat already know this)...

Phase is a time phenomena and refers to the beginning of a sine wave cycle relative to another sine wave of the same frequency. See first attachment.

Split phase 240v/120v service has no "phase" because Line 1 and Line 2 have no time difference between their waveforms. What is being discussed (incorrectly, usually) is *polarity*.

Alternating current has no absolute polarity (although waveforms can be inverted); sine waves, when added, results in a increase in voltage or a decrease depending on their TIME (phase) relationship. Since the center tap of the transformer secondary that creates the "neutral" (or "grounded, current-carrying conductor in Code-speak) does not change the *time* relationship between L1 and L2, there is no 'phase'.

In three phase systems the start of each sine wave cycle begins when the previous phase is 120° ahead. Think of a circle perimeter divided into thirds (120°) and envision each 1/3 as a generator coil for a respective Line. Remember that generators ROTATE... and the idea "phase rotation" should become clear. Anyone who has wired 3 phase electric motors and had them run backwards knows how this works... The second attachment shows the 3 phases displayed as they normally occur, and shows the 120° distance between waveforms.

Mike (NoShockZone) Sokol is an RVer, music conservatory instructor, musician, and electrical engineer. A couple years ago he had a project to demonstrate various "flavors" of 3 phase power to a large, national A/V firm whose employees blew up a bunch of expensive equipment by tapping a high-leg Delta system thinking it was a Wye... so devised some ways to show what's happening. I've borrowed two of his screen shots. Thanks, Mike!

seadogjim · 10-04-2020, 10:37 AM

Cavie, thanks for all your help and insight. The pedestal has two breaker boxes. The one on the top has first a 200 amp breaker with the wires going from that breaker to a 70 amp breaker below it. The lower box has the“Standard“ breakers for 20 amp, 30 amp and 50 amp. It was the 70 amp breaker in the upper box that was placed one position to the left on the wrong rails. Once the new 70 amp breaker was put on the correct rails it solved the problem so that the 50 amp breaker had 240 V between both hot legs thus, providing 50 amp power to the RV.
I have a 50 amp surge protector and it shows all green lights indicating no problem with the electrical service. Hope this helps explain it. Thanks, Jim

Skip426 · 10-04-2020, 11:42 AM

Question

Was the post worked on , without your knowledge ?

Your original post said no issues in months in the site.
Or was the problem there all along and didn't come to your attention until your use exceeded 30 amps and sheading started?

seadogjim · 10-04-2020, 11:56 AM

Skip 426, I’m sure the post has not been worked on since I’ve been there. Since I have been in that site for several months, I think it’s almost impossible I would not have noticed that I was only getting 30A, especially in the summer with both ACs running. Not sure what prompted the problem to appear, but my EMS was definitely showing only 30A the last few days until we put on the new circuit breaker. Who knows, maybe the notorious electrical gremlins!

tomcaut · 10-08-2020, 04:04 PM

It's wet simple , I chg about 30 a yr out , the rv sitting there , ruins the breaker after a bit, 1/2 the breaker is bad , have them put anew 50 amp in an you willbe good to go . Trust me I had to learn this the hard way , all test good till that 1.2 gets a load an pop , 1/2 your 50 is gone , o u can't flip it an it will com back

tomcaut · 10-08-2020, 04:04 PM

Supposed to say real simple!!

Johnynorthla · 10-08-2020, 04:05 PM

Don’t go crazy, Try another pedestal first! Then go from there.

tkenned2 · 10-08-2020, 05:07 PM

Make sure that your power share did not set to 30 amp. My old MH had the power share and if the power share was set at 30 amp, that's all I got. Only one ac would then work and if pushed it and tried anyway, it caused the CG breaker to trip since 30 amp is all I had.

Ray,IN · 10-08-2020, 05:22 PM

Quote:

Originally Posted by shootist

I've stayed in parks with 3 phase power. Each park leg reads 120 to ground/neutral, but 208 between the legs due to being out of phase. That may be what confused your electronic load shedding. Worth a check.

No RV is capable of running on 3-phase power, that is industrial power only.

shootist · 10-08-2020, 06:08 PM

Quote:

Originally Posted by Ray,IN

No RV is capable of running on 3-phase power, that is industrial power only.

Not running on three phase. Running on 2 120v lines out of phase. Only slightly effects the neutral load. You still get 207 or 208 between the legs. Try actually checking the power at the pedestals in the old parks. Grand canyon rv in Ashfork is one I remember specifically.

Alby · 10-08-2020, 06:34 PM

Try plugging it into a different site and see if you get the same results.

SKP Kirk · 10-08-2020, 06:58 PM

Quote:

Originally Posted by seadogjim

Problem solved, it was an incorrectly installed breaker that was only allowing one leg of 120 V to feed through.

That is the only simple way for that to have happened, but they must have replaced your circuit breakers to cause that to happen. In a normal 50A RV outlet there are actually 2 50a breakers, one taking power from L1 and the other from L2. They get power from a center tapped transformer with the neutral connected in the center, thus the opposite phase relationship and the reason for 240V between the two. You actually have a theoretical 100A total supply but that also requires each leg to have exactly 50A of load. In reality you usually have about 80A of total usable power.

aether_one · 10-08-2020, 07:18 PM

Quote:

Originally Posted by Solo_RV_Guy

Dont get me started on "phase." Okay, too late... for those at home (Hohenwald and Cavie and Twinboat already know this)...

Phase is a time phenomena and refers to the beginning of a sine wave cycle relative to another sine wave of the same frequency. See first attachment.

Split phase 240v/120v service has no "phase" because Line 1 and Line 2 have no time difference between their waveforms. What is being discussed (incorrectly, usually) is *polarity*.

And since L1 and L2 are 180 degrees out of phase at any instant in time they have opposite polarities.