half amp problem

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catawba1

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This weekend our 50 amp hook up only gave us power to  the lights and Frig , when i plugged in to the 30 amp everything worked  both airs W/D etc etc , I ran the generator and no problem everthing worked , we chose to leave it hooked to the 30 amp shore power , the weather was cool enough we did not need the air cond ,  I had this same problem last weekend at a different camp ground so its my RV that's got the problem , is this a dealer fix or something I am over looking .
 

Gary RV_Wizard

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The lights are 12v, so not affected by shore power (until the battery runs down, anyway). Did the fridge shift to propane mode or stay on electric? The fridge will run fine on 12v only once it shifts to propane.

From your description, it sounds as though the 50A outlet on the site had a problem and wasn't delivering power to one of the hot legs. Or maybe even neither. When you switched to the 30A outlet, the available power was shared via the 30/50 adapter to the twin hot legs on your 50A cord and everything worked. That pretty much says that everything in your RV was working fine.
 

Wizard46

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If the same problem on a different campground pedestal, then the problem is probably with your cable or transfer switch. If it works on generator the probably not a tripped breaker.

I would start be checking the voltages on the transfer switch. You should read 120V to neutral on both hot wires from the cord. If thats reads good then check the output from the transfer switch, you should read the same.

Jerry
 

Water Dog

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As Gary already mentioned, if everything is working through a 30 to 50 amp adapter, then you ARE getting power up both legs through the transfer switch and the breaker panel. The issue would have to be at the pedestal. Either the 50 amp outlet itself, the service to it, or the circuit breakers protecting it.
 

gwcowgill

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I have had the same problem...When testing with a meter it turned out to be a power pedestal problem.  It may be coincidental that you ran into 2 bad pedestals. Check it with a meter before replacing parts.
 

catawba1

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OK thanks , I will check all this in the morning , i take it if I trace the cord out it will lead to the transfer switch, hard to believe that i got 2 bad pedestals at 2 diff CG , but never know . I was going to unscrew the plug and check the wires / connections but wasn't sure what color wire means what. i will search transfer switch tonight and try to get a clue at what I'm looking for .
 

Water Dog

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catawba1 said:
OK thanks , I will check all this in the morning , i take it if I trace the cord out it will lead to the transfer switch, hard to believe that i got 2 bad pedestals at 2 diff CG , but never know . I was going to unscrew the plug and check the wires / connections but wasn't sure what color wire means what. i will search transfer switch tonight and try to get a clue at what I'm looking for .

Try flipping both the 50 amp breakers (on the pedestal) off, then back on. Sometimes one side is tripped but doesn't really look like it.
 

Just Lou

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It doesn't necessarily have to be a seriously defective 50amp CG pedestal.  Take a good look at your 50amp cord plug, it just may be that something about it mates well with your seldom used (unworn) 30amp adapter,  but doesn't always mate well with a slightly worn or loose 50amp receptacle. 

Make sure the prongs are perfectly aligned and clean.

BTW - If you can inspect the wires inside the plug, you should do so.  Make sure that each are tight.  You don't have to know anything about proper colored wires to make that judgement.
 

catawba1

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I checked the plug this morning and see no problems with it, when using the 50 amp both fans ran on AC units but compressor's would not kick in ,you could the rear 1 bump like it was trying to run,, the lights came on the washer dryer but it would not run on 50 amp , both times we plugged in to the 30 amp and everything worked as expected , the green lights on the energy management board would swap back and forth from 30 to 50 never stopping on 1 or the other , but when plugged into the 30 amp it would stay on 30 amps , it goes to 50 when on Gen set , I'm hooked up to 20 amp at the house and can run 1 air, front or rear , I'm thinking now i may have a bad board or something going on in the board  or relays .Any suggestions.
 

Ernie n Tara

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Unavoidable fact! If everything works on the generator and when using the 30A adapter- these use both legs of the cable, the problem is the connection at the service pole as noted above. The 30 Amp adapter uses both legs of the cable so everything else is demonstrated to work.

Ernie
 

Water Dog

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Ernie n Tara said:
Unavoidable fact! If everything works on the generator and when using the 30A adapter- these use both legs of the cable, the problem is the connection at the service pole as noted above. The 30 Amp adapter uses both legs of the cable so everything else is demonstrated to work.

Ernie

I agree Ernie, but there is one thought going on in my pea brain. I'm not actually sure exactly how the power management system is wired in. Could it be that a control or signal wire or relay be disconnected or bad thereby making the management system think there was only one leg coming in on 50 amp service, but seeing 30 amp service as okay? That is the only other possibility I can think of (and not even sure it's possible) if it is not the pedestal (or plug, as Lou pointed out).
 

gwcowgill

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It is possible you have a problem in the power cord coming in to the RV but as stated above, if everything works on the generator you can bet that every thing from where the power cable hooks up to the coach is good. You could have a loose connector where the cable hooks up at the transfer switch or a bad cable. I still suspect the pedastals as the culprits.
 

Gary RV_Wizard

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I'm not actually sure exactly how the power management system is wired in. Could it be that a control or signal wire or relay be disconnected or bad thereby making the management system think there was only one leg coming in on 50 amp service, but seeing 30 amp service as okay?

No, it doesn't work that way. The 30/50 adapter simply connects the single 30A hot wire to both hot terminals on a 50A cord. From that point on, everything is the same.

If there is a Energy Management System in the RV, it samples the incoming power to detect 30A (120v) vs 50A (240v) so it can manage amp loads correctly, and there may be an EMS control circuit that detects generator source, which is usually greater than 30A power but less than full 50A. That control circuit, however, just helps the EMS to decide whether to manage loads or not.
 

Water Dog

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Gary RV Roamer said:
No, it doesn't work that way. The 30/50 adapter simply connects the single 30A hot wire to both hot terminals on a 50A cord. From that point on, everything is the same.

If there is a Energy Management System in the RV, it samples the incoming power to detect 30A (120v) vs 50A (240v) so it can manage amp loads correctly, and there may be an EMS control circuit that detects generator source, which is usually greater than 30A power but less than full 50A. That control circuit, however, just helps the EMS to decide whether to manage loads or not.

Thanks for the clarification Gary. I was aware that the 30-50 adapter fed both legs, but wasn't sure what the EMS used to detect the difference between the 30 and 50 amp services.
 

Ned

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The EMS detects 50A service by seeing 240V between the 2 legs.  On 30A the voltage is 0V because the 2 legs are on the same phase.
 

catawba1

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I took the RV to local dealer this morning and plugged into their 50 amp shore and everthing worked as should and the green light panel showed 50 amps , they are going to go over the connections and check ,but appears that I got 2 bad  50 hook ups at 2 Different camp grounds , I was thinking about buying this item (Portable Surge Guard With LCD Display- 50 Amp )  this would help detect a problem in the future  right . Thanks for all your help, we just went from  C class to our first A class and what a learning curve , and how things are so much different .
 

Ned

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catawba1 said:
I was thinking about buying this item (Portable Surge Guard With LCD Display- 50 Amp )  this would help detect a problem in the future  right

This model is owned by quite a few of us and is about the best you can get for power and surge protection.  There is a portable model as well, but I prefer the hardwired unit.
 

Rich D.

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Would it be possible that a protection device shut down because a 50 amp plug was inserted into a live outlet at an angle that connected the ground and hots before the neutral? That is why it is always recommended to plug into a dead outlet then turn the breakers on. Otherwise it is possible with the 50 amp plug to have an open neutral momentarily when plugging in.
 
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