Can't get 50 Amp to come on

The system sees 240 as a result of 2 120 legs.  If one side of the 50A is dead, the rig will see 120 on one leg, 0 on the other and can see it as what a 30A would be.  I think you  guys know this but it didn't read that way.

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Possibly true, Bill, but without knowing the logic of the EMS, its hard to say for sure. A normal 30A circuit would still have 120V on each leg in the coach, where the EMS "sees" the available power.  It should never expect to see  a "0" on either leg, not even when on 15A.  That's because the 15/20/30 adapters short the two legs together, feeding both from the single 120V line available in 15/20/30A outlets.  If the EMS panel checks the voltage across the two hot legs, it will actually see a 0 except when on full 50A service. That's because both legs are at 120V in the same phase on a 15/20/30A connection and the difference between them is therefore 0.

Someone posted a link to his owner's manual

Here is how it works.

Imagine the legs like this    X----0----Y

Now, when hooked to mains, measuring X to 0 normally gets you 120, likewise measuring Y to 0 gets you 120
but measuring X to Y, 240

Now, if the voltage, as measured between X and Y is zero, or something close to it, you do not have 50 amp power

That is, in fact the logic his system uses

So, if the park is wired X-0-X or Y-0-Y the power controller says "Ah, 30 amps"

(and by the way, if it did not a fire in your rig is a distinct posibility as the center leg (0 in the drawing above) melts at 100 amps, twice it's rating)

So, the solution is to take a Multi meter and measure the voltages at the outlet.

At the 50 amp outlet you will have 4 slots, one is significtantly different than the other, this is safety ground

One is oppisite it, this is "ZERO" in the drawing above,  Measure between the other two, if zero, you really want your power controller throttling down your consumption.. Complain to the park manager as well

(Note, also measure left and right to center just to be sure it's not a tripped breaker somewhere, if there is a tripped breaker, bring it to the attention of the park manager, however don't complain

Lot of good info here, thanks to all. 

Some additional facts in my scenario: 

I had 50 Amp service yesterday, before I moved my coach two spots over.
I'm plugged into a 4-prong outlet.
I tried connecting to another nearby outlet (not the same as yesterday) and still have 30 Amp showing.

My guess is either the campground has two miswired outlets, or more likely my Intellitec panel has lost it's way.  I'm guessing the latter, because the DC panel is also acting up, in that the LED display is showing "????????????".

I guess it's time to take it in for service, unless somebody has a technique for "resetting" the panel.

Dave

Dave,

Can you come up with a model# or part# for the Intellitech?

I mentioned using a multi meter to measure the voltage across the different legs of the 50 amp service.

Just so you know such a meter should be part of your tool box, you can get these meters for, well, I've found perfectly usable ones in a dollar store... I've also seen them with price tags in the 500-1000 range, for your needs they more or less all work the same

The campground folks were supposed to check the outlet voltage today, but I need to call to find out.

The Intellitec panel does not have a model number on it, and I can't seem to find the owner's manual in the box full of documentation the HR provided (it could be better organized, IMHO)

I'll keep you posted...

Dave

Update from the campground host -- although the volt-meter reads OK, there are 4 sites in the campground that are supposed to be 50 Amp, but don't show up that way.  Other RVers have had same problem, and I happened to pick one of those 4.  That would explain why I had 50 Amps Saturday, but not Sunday.  Good news is that my coach is not broken. 

Thanks again!

Dave

that is good news.

Thanks for the feedback Dave. You had us all guessing, but the campground wiring being the culprit is good news.

One less trip back to the dealer for warranty. ;D ;D

Dave,

although the volt-meter reads OK, there are 4 sites in the campground that are supposed to be 50 Amp, but don't show up that way.

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Are you saying the meter DID read 240 across the two hot leads? That I don't understand at all. Must be magic ;D

I wasn't the meter-reader, but maintenance guy seems to think both leads are hot, but they are in phase, as opposed to having opposite phases.  I think I can buy that.  I'm hoping they'll fix it, so I don't have to move (again).

davem1958 said:

....both leads are hot, but they are in phase, as opposed to having opposite phases.

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That could explain a lot Dave.

Sounds to me like the "METER" in question is an outlet volt meter such as the one I have in my rig.

Not a multi-meter (I have a few of those too) which would have diagnosed the problem in a heartbeat if used by someone who knows how to use it (IE: ME, and a good number of other forum members)

Dave: Here is how you test that, First a caution

DO NOT TOUCH THE METAL PORTION OF THE METER PROBES DURING THIS TEST

Set the meter to at least the 250 volt AC range (Go higher, not lower if you must)

Unplug the 50 amp plug, there are 4 holes in the socket, 3 flat, one round

Normally the round one is either on top, or bottom, disregard it and the one oppisite it

CAREFULLY insert the probes in the other two slots, you should see one of three readings

1: Zero or near zero  this may be probes not making contact (you should feel when they make contact) or it may be the problem.  See next step

2: something close to 240 volts (this is good, in fact it's normal)  Skip remaining steps you are done here

Next step
If you got ZERO in the first test move ONE probe, (just one) to the other flat slot, you should now see one of two readings

120 volts (Maintance guy is likely right, go to last step)

Zero volts (Probes not making contact but still go to last step)

Last step

Move the probe you did not move in step 2 to the other flat slot (the one the other probe was in in step one)

Zero volts, not making contact  120 volts, the maintance man IS right, both hot, both in phase

NOTE if you get 120 volts on one side but not the other... Then there is a problem for park maintance to fix

The round hole is safety ground... It is not part of this problem

If you are uncomfortable playing with voltages which can easily kill you.... Have someone who knows what they are doing check the outlet.. Park maintance may be a good choice

but maintenance guy seems to think both leads are hot, but they are in phase, as opposed to having opposite phases.

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That is what several of us conjectured and exactly explains your symptoms. 

Don't count on a quick fix from the campground. Changing from 120V to 240V is probably not a simple change for them, unless the situation was a simple mistake in the original installation as opposed to an intentional choice is the design.  My guess is that it was an intentional "short cut" in the campground power distribution system, in which case the upgrade will require significant effort and more than a little expense too.

RV Roamer said:

That is what several of us conjectured and exactly explains your symptoms. 

Don't count on a quick fix from the campground. Changing from 120V to 240V is probably not a simple change for them,

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Let's see, First you need to map the power lines, Then you take a backhoe and start digging (or at the very least a ditch witch.

Yup, not an easy job at all

Unless someone with far more intelegence than the average camp ground installer put in conduit, then it's easy

Right, Gary. Most likely they had run just 3-wire cable to the post (hot, neutral, ground) and wired the hot to both inputs of the double c.b., and the outputs to each 'hot' leg of the 50A receptacle.

Maybe the CG owner was a boater at one time. There are two flavors of 50A in the boating world, 120V and 240V. Different plugs/receptacles so you can't mix them up or plug into the wrong one. But this guy might have been exposed only to the 120V version.

Since only 4 sites are wired in this fashion, I'm betting they used the 3-wire shortcut that Karl mentioned on those sites.  It could well be they don't have sufficient power at the distribution panel to supply all the sites with a full 50A/240V, so they cut the available power to 4 sites in order to get an OK from the local building codes inspector. A 50A/240 circuit at  the distribution panel could supply TWO sites with 50A/120V service. And 50A/120V will power a big RV nicely, the same as a 6 KW onboard generator does. [If only it weren't for Dave's Energy Mgm't System "mistaking" it for 30A service.]