Forum Discussion

AikenRacer's avatar
AikenRacer
Explorer
Dec 25, 2017

Open Ground Electrical Issue

Several years ago, I had a 30 amp outlet installed at my house. Prior to going on a trip, I bring the MH to the house, plug it in so I'll have power to run the fridge and sometimes one AC while we pack. All total far less than 30 amps. Done this many times. I use an inline Progressive EMS. The MH has been at the house for two days now. For this trip, only the fridge runs, no heat or ac. Today, I hear a switching sound from the inverter and it turned out to be the EMS blocking the power to the MH. Error code says open ground. I use 2 30 amp drop cords and an adapter to go from the outlet on the home to the EMS. So I start looking and see that one of the male hot legs of the 30 to 50 amp adapter is melted along where it plugged into the female end of the cord. What would cause this?? Please answer in layman's terms as I am no electrician by any means. Thanks!!
Class A
  • bullydogs1's avatar
    bullydogs1
    Explorer
    Dec 25, 2017
    Can you find another 30 amp to plug into to?...as it could be cord/ground plug on cord or the 30 amp itself...Get a tester and use a 15 amp converter plug...is ground showing good?...if so, it is the cord, if ground is showing open it is the plug.
  • wildmanbaker's avatar
    wildmanbaker
    Explorer
    Dec 25, 2017
    Usually a bad connection, that causes excessive heat due to either high current, or actual arcing. Check you "drop cords" also.
  • cbshoestring's avatar
    cbshoestring
    Explorer II
    Dec 25, 2017
    "I use 2 30 amp drop cords and an adapter to go from the outlet on the home to the EMS"

    I hope they truly are GOOD 30 amp extension cords. One of the resident electricians can explain the theory of loosing "power" the longer the run is. Especially with inferior extensions.

    Melting is caused by heat.

    Heat is caused by resistence.

    Two common ways to produce resistence are: overloading or a loose connection.

    Assuming you are NOT overloading, and the extensions are of sufficient guage to handle the load over the legnth of run you describe, I would look to make sure you have a tight connection between the male/female plugs.

    Then again...me twuck driber, and only part time handi-dude---- not electro dude.
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Dec 25, 2017
    Do you keep the male prongs bright and clean so that they have the best possible electrical connection? Poor connections heat up. I haven't found a good way to clan molded female plugs.

    I'm slowly replacing all of my plugs with Camco plugs. They come apart without removing the wires for significantly better cleaning.
  • centerline's avatar
    centerline
    Explorer
    Dec 25, 2017
    I agree with the answers already given.. and once the plastic/rubber? has melted, an internal short is likely to happen, and so you get a ground fault..

    just because amperage has passed thru a connection yesterday, is no indication that the connection is capable of carrying the same amperage today..
    without the proper circuit protection, this assumption will eventually lead to a fire...and does too often, as a bad shore power connection is the leading cause of marina boat fires.
    admittedly, the humidity and corrosion factor is many times greater in that enviroment which amplifies the poor connection, but its still the poor connection that causes the heat.. and the heat leads to the direct short/fire.
  • pianotuna's avatar
    pianotuna
    Nomad III
    Dec 26, 2017
    Hi CA Traveler,

    I've had four female Camco plugs fail. They were carrying no more than 15 amps (that's all the shore power I had).

    I moved to Progressive females and have had no more failures.

    The male Camco seem to be ok.

    CA Traveler wrote:
    Do you keep the male prongs bright and clean so that they have the best possible electrical connection? Poor connections heat up. I haven't found a good way to clan molded female plugs.

    I'm slowly replacing all of my plugs with Camco plugs. They come apart without removing the wires for significantly better cleaning.
  • AikenRacer's avatar
    AikenRacer
    Explorer
    Dec 26, 2017
    If the Camco plugs are the yellow ones with the handles, that is what I am using. Maybe I just need to get a longer 30 amp cord instead of using two.
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Dec 26, 2017
    AikenRacer wrote:
    If the Camco plugs are the yellow ones with the handles, that is what I am using. Maybe I just need to get a longer 30 amp cord instead of using two.
    How would that help when you said the 30/50 adapter failed?

    Low amps and hot plug as posted suggests a bad connection. Maybe the adapter just failed? I have one showing slight overheat but a A/C was likely involved.

    Yes Camco yellow plugs with handles. Take them apart and check that the wire clamp is tight and clean. For corrosion you can use vinegar and baking soda to clean. And very fine sandpaper as required.

    Also suggest you use a digital voltmeter in the rig and watch the voltage. It should not go below 10% or 108V. The EMS will allow lower voltage before it disconnects. But a portable EMS is not checking rig voltage.
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Dec 26, 2017
    Also rigs vibrate and bounce down the road and hence things become loose. Unplug the rig, gen CBs off and check all wiring connections. Remove CB cover, ATS cover, junction boxes, etc. It's not uncommon to find connections that are not tight.

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