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Mike_Schriber's avatar
Jul 22, 2017

Microwave and converter fried at campground

Just got set up at a campground in Colorado Springs and I have a big problem. Everything seemed to be working correctly electrically initially but when we came back to camp I found the front air conditioner breaker blown, the microwave off and the battery not charging. I reset the AC breaker and the unit seems fine.
I then checked the outlets for the microwave and converter (each on a separate breaker) and they had power. The converter smells fried and is not putting out any power and the microwave appears to be history.

Doing more testing, I used a circuit checker to test the other outlets. One circuit showed that the hot and ground were reversed (the laptop plugged into that circuit also stopped charging). I switched from the 50 amp plug to the 30 amp and the circuit showed good. I'm now figuring that one leg is wired wrong at the pedestal on the 50 amp outlet. However, I switched back to the 50 amp circuit to double check and now the circuit shows normal.

I'm really stumped. I know it's not anything on the motorhome side but I can't explain the shifting readings. I plan to have some words with the campground management in the morning and I'd love to have some idea what's going on with their power before I do.

Any thoughts?

Thanks!

46 Replies

  • Your situation is why I have a Progessive Industries 50AMP EMS. Any problem from the pedestal would be caught BEFORE the RV gets any power.

    With me,a nearby lightening strike fried my fridge and damaged my INverter. THEN I bought the EMS. No problems since even with thunderstorms.
  • wnjj's avatar
    wnjj
    Explorer II
    You had an open neutral between the campground and your RV.

    I assume you used one of those 3-light testers? All the lights do is show voltage between each of the 3 pairs of pins on a 120V recepatcle. They are literally 3 lights wired between the 3 combinations of 2 pins. If there's voltage between the pins, the light lights up. Yellow lights are between hot and neutral and between hot and ground and the red is between neutral and ground.

    Normally in a working 120V recepatcle there is only voltage between hot and neutral and between hot and ground. Those are the 2 orange lights. What it calls hot-gnd reverse (one orange and a red light) is when there is power between ground and hot (orange) as well as between ground and neutral (red). It assumes the ground and hot have their wires swapped. With this assumption there is 1 hot and 2 "cold" pins.

    The problem is with an open neutral on the 240V RV supply, the neutral will move closer (in voltage) to the hot leg with the most load. What the 3-light tester sees at a 120V recepatcle on that leg is power between hot and ground and also between neutral and ground...just like hot-gnd reversed, except now there are 2 hot and 1 "cold".

    When the open neutral happened, half of your RV's 120V circuits dropped to nearly 0 (the half that showed the reverse) and the other half climbed to nearly 240V. The AC likely pulled the one leg way down, eventually tripping the breaker but not before frying the microwave and other things on the opposite leg.

    The issue may be in the pedistal or it may be with your cord. Since unplugging and replugging in fixed it, it could be the plug, recepatcle, a wire behind the recepatcle or simply the connection between them. It may be tough to prove the park is as fault (if they even are).
  • Yep. I was going to ask around tomorrow. However, I have a feeling that it's something with the pedestal. Getting a reversed hot and ground on one circuit isn't likely to be utility company related.

    I'm still trying to figure out how something like that can fix itself...
  • might talk to other campers

    IF there was power line problems, you won't be the only one

    BUT it it was the utilty company, you will have to deal with your own insursance for fixing this

    thats why so many people use a 'over voltage protection' and under vlotage and transient protection, in short a 'cut out device that monitors line and disconnects the RV
  • I'm not sure what might have happened voltage wise. The circuit tested indicated that hot and ground was reversed but I haven't been able to repeat that reading. It did seem to be normal at first and that changed during multiple plugging and unplugging as I switched from the 50 amp and 30 amp outlets.

    I'm having trouble seeing how such a reversal can be intermittent.
  • It takes well in excess of 200 volts RMS to damage an OEM laptop brick (despite what its label may say).

    You need "proof" an that proof can be best created by use of a multimeter and cellphone camera. Have a 2nd help with the images.

    Meter probes stuck into campground receptacles. Image shows probes, receptacle and meter reading. Same with block type plug-type connection verifier. With meter get L1 to L2 voltage. L1 to LO and L2 to LO. L1 and L2 to socket earth ground ground. Socket earth ground to actual ground around your feet.

    I would not give advance warning. Turn images into glossy photographs. Then present management with a stack of photographs at your first announcement. They'll hate that for good reason. Attorneys despise documentation for a reason.

    Good luck.

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