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mjm2198's avatar
mjm2198
Explorer II
Aug 24, 2025

50 amp outlet/surge protector voltage error

First time, I apologize for the long post. I hope I can get some insight, because I am completely lost.

I have an outlying shop that I installed a 50 amp outlet to using a 50 amp box with 6/3 copper wire. Testing it with a multimeter I get 120 on each leg and 240 combined, as well as 120 from the main breaker and 50 amp breaker. However, when I plug in my 50 amp surge protector it shows an error of "E2: Voltage over 132V". The weird thing is, when I plug my protector into a 50/30 dog bone with the 15 adapter the surge protector turns on with no issue showing 119V so I dont believe it's the protector.

Any suggestions would be appreciated because after checking and changing neutrals and grounds and checking the same things over and over, I have no idea the next step and I really dont want to spend thousands having a company wire something in. TIA.

For context I have a new GEARGO RV-04 50 amp surge protector. 

Asking for Advice
Travel Trailer

8 Replies

  • Grit_dog's avatar
    Grit_dog
    Navigator II
    Aug 27, 2025

    Is there a problem with how it powers the camper?  If so, what?

    It’s not rocket surgery. If you got it wired up right at the panel and outlet, does it run the camper properly or not?

    A surge protector is not a required addition and it may not be working right?

  • Grit_dog's avatar
    Grit_dog
    Navigator II
    Aug 26, 2025

    Maybe I’m confusing things. But you said you have a 50a rv surge protector so 4 poles on the male and female end, correct?

    You mentioned testing it with a 50/30 dog bone and 15a adapter meaning (I’m. Asking) you plugged into a household outlet to test it. 15 adapter to dog bone to 50a surge protector?  If so this could never show more than 120v power because it only has 1 leg of power to it. 
    what you’ve done sounds correct in your wiring at the panel to outlet. 
    Does the RV not work on both legs of power if you plug it in to your 50a outlet?

    Are you trying to solve another issue you have with the RV or just wired this up and only plugged in the surge protector?

    Have you used this surge protector on another 50a source without issue?

    maybe it’s the surge protector having issues as it seems you wired it right. 

  • StirCrazy's avatar
    StirCrazy
    Moderator
    Aug 25, 2025

    does the display show the voltage or does it go off and just give you the E2 error?

    RV 240V is made from two 120V lines a neutral and a ground, I am assuming that is what you did by your post.  

    I am not sure what you mean by "checking and changing neutrals and grounds"  you can't change up the neutral and the ground.  so looking at the plug in the ground is the "D" shaped hole, the neutral is the long one directly below it, the outer two are your two hot 120 wires.

    so when you plug it in does it do that right away? or after a while? 

    electrical are always the hardest to trouble shoot on the internet as there are so many different things that could be causing it.  

    • mjm2198's avatar
      mjm2198
      Explorer II
      Aug 25, 2025

      Thank you for your response. The sure protector immediately goes into error mode with nothing but "E2" displayed. 

      Correct, that's how's it's wired. I apologize for not being more clear, when I say I changed the ground/neutral, I just moved them up on the bus bars in the inside breaker box, and moved the 50amp breaker down a slot.

      It goes into error immediately. All of the voltage reading I've gotten were correct, but im assuming there's an issue under load because it's doing it when plugged in.

      • StirCrazy's avatar
        StirCrazy
        Moderator
        Aug 26, 2025

        one final last question, the two hot lines are on opposite phases are they not?  if they were on the same phase then I could see it causing this issue, if its a standard panel and a double pole breaker there should be no way to mess this up but its worth the ask.  

        the only other thing I can think of, is a bad surge protector.  is there another one you could borrow and try?  

  • Grit_dog's avatar
    Grit_dog
    Navigator II
    Aug 24, 2025

    I assume you have a RV 50a config wired in.  But sounds like you have it wired 240v not 2- 120 legs. 

    • mjm2198's avatar
      mjm2198
      Explorer II
      Aug 25, 2025

      Thank you for the response, that's correct, 50a breaker going to a 50a outlet box. Checking the outlet with a multimeter, each side is 120v on its own and 240v if I test them together. That's why im so lost.

      • jkwilson's avatar
        jkwilson
        Explorer III
        Sep 06, 2025

        Measure while there is a load on the circuit. Hairdryer or similar. My bet is you’ll find one leg is too high and one too low, but still adding to 240V. Neutral problem.

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