Hello Guest

Open Ground Error on 50 Amp Coaches

  • 1 Replies


  • ******
  • 783
  • John and Carrie
    • View Profile
    • Zigzag Mountain Art
  • OwnPC: Yes
  • NewUsed: New
  • PurchDate: November 2016
  • Model: 2552
  • ModelYear: 2017
  • Slide: Yes
  • IntColor: Graystone
  • ExtColor: Graystone
  • Location: Oregon Mountains
Open Ground Error on 50 Amp Coaches
« on: July 04, 2018, 05:56:12 pm »
This only applies to 50 amp coaches that have a surge suppressor (EMS) that will shut off shore power if an error occurs.  Currently Phoenix installs a Progressive Industries EMS-HW50C for this purpose.

If you have this configuration and you get spurious "Open Ground" errors it might not be a real error or the fault of the EMS.  "Open Ground" is error E-2.  After getting the "open ground" error at a number of different campgrounds where testing with a meter or another surge protector proved there was no error I suspected the EMS was faulty.  However, careful testing proved that while there was no "open ground" at the pedestal there was an "open ground" at the input terminals of the EMS.  This lead to the suspicion that the power cord was faulty but testing showed it was fine.  The only place left was the input receptacle on the side of the coach and I discovered that the ground pin was flattened enough that in some circumstances it was not making contact with the shore power cable.  This lead to the "open ground" error from the EMS.

In one case all worked fine when I plugged in in the evening but suddenly at 8am the power shut off.  The rising sun had heated up the receptacle on the side of the coach enough that we lost contact on the ground pin.

I gently bent the center bar of the ground pin out toward the center of the receptacle and so far have had no additional errors.  I am not sure if this is just my receptacle or a fault of that model but if you get an E-2 error check the input receptacle before suspecting the EMS is faulty.



  • *****
  • 162
  • Gary and Susie
    • View Profile
  • OwnPC: Yes
  • NewUsed: New
  • PurchDate: P.U. 6/11/18
  • Model: 3100
  • ModelYear: 2018
  • Slide: Yes
  • IntColor: Nightscape (Cherry)
  • ExtColor: Graystone (FBP)
  • Location: Northern Michigan
Re: Open Ground Error on 50 Amp Coaches
« Reply #1 on: July 04, 2018, 08:46:29 pm »
Thanks for a nice written and pictorial explanation.  I will definitely keep that in mind if we start having that problem.