Will The EMS-PT50X 50amp EMS operate properly if plugged into 30amps? Need to know before I commit...No response from Progressive Ind.

I am going to take a stab that it won't allow power if you are only supplying power to only one of the "legs"..Page 6 of the manual..HERE"Example: The EMS shuts down power for low voltage on Line-1 and then power is restored. "In a nutshell it is supposed to not allow voltage to pass if it is below 104V.. Guessing that would also mean that BOTH L1 and L2 must have voltage higher than 104V..Page 5 seems to indicate that both L1 and L2 need voltages higher than 104V.."NOTE: If the display indicates an error code other than E 0 or E 10, the EMS will not allow power to the RV. "Now if your 30A 120V adapter were to supply voltage to both L1 and L2 then it "might" work but if unit is looking for L2 to be 180 degrees out of phase (the way it should be) then I suspect the unit won't pass voltage on to the trailer..But, hey, you might get lucky and the EMS doesn't care if L1 and L2 are in phase..All you can do is try it with the EMS and if it doesn't work just remove it or bypass it?

Yes with the standard 30/50 RV adapter. Aspects of the above post are incorrect, as the unit doesn't know or detect any aspect of 120/240V power, only that both legs have 120V within specs.

BTW The 120/240V 50A is SINGLE PHASE, it's a common misconception that it's 2 phase, etc. Split phase is a reasonable description.

CA Traveler wrote:BTW The 120/240V 50A is SINGLE PHASE, it's a common misconception that it's 2 phase, etc. Split phase is a reasonable description.:RConnect L1 and L2 together on a proper 120/240 circuit and see what happens..L1 and L2 are 180 degrees "out of phase" compared to each other and even the neutral and that IS correct.When L1 is going in positive direction L2 is going in a negative direction. When L1 is going negative the L2 is going positive.And there is ZERO "wrong" with what I posted.The problem you have is "semantics".There are 30A to 50A dogbones that only supply L1 with 120V connection and there are 30A to 50A dogbones that will connect both L1 and L2 to the single 120V 30A power source..As I told the OP, all they can do is try it, if their dogbone does not connect both L1 and L2 together then their EMS will not allow voltage to pass..However a REAL "EMS" in theory should not allow ANY voltage pass that has the exact same direction waveform on L1 and L2 as that is a violation..

I can't answer definitively, but I can say that a EMS-HW50C works just fine with a Camco 30->50 dogbone and also with a Camco 20->30 with the 30->50 dogbone.

50amp EMS w/surge | Good Sam Community

Gdetrailer
Explorer III
Apr 17, 2021
I am going to take a stab that it won't allow power if you are only supplying power to only one of the "legs"..

Page 6 of the manual..

HERE

"Example:
The EMS shuts down power for low voltage on Line-1 and then power is
restored. "

In a nutshell it is supposed to not allow voltage to pass if it is below 104V.. Guessing that would also mean that BOTH L1 and L2 must have voltage higher than 104V..

Page 5 seems to indicate that both L1 and L2 need voltages higher than 104V..

"NOTE:
If the display indicates an error code other than
E 0 or E 10, the EMS will not allow power to the RV. "

Now if your 30A 120V adapter were to supply voltage to both L1 and L2 then it "might" work but if unit is looking for L2 to be 180 degrees out of phase (the way it should be) then I suspect the unit won't pass voltage on to the trailer..

But, hey, you might get lucky and the EMS doesn't care if L1 and L2 are in phase..

All you can do is try it with the EMS and if it doesn't work just remove it or bypass it?

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