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hbrady's avatar
hbrady
Explorer
Jun 25, 2017

Open ground detected

Searched the forum and was surprised I didn't find anything on this topic. We are taking our TT on our first boondocking adventure next week and wanted to test out our new Champion inverter/ generator. Got it running, plugged in TT and my PI (hard wired) EMS tripped with an open ground error. In the past I've hooked up my TT to my old generator without grounding it and the EMS didn't detect and issues but it's also a big metal frame unit with metal legs on the ground. Before I go buy grounding rod I was just wondering if other people with inverter/generators normally ground them, like manual says you should ;). Thanks!
  • The IQ2000 spec sheet says "neutral bonded to ground". It is in so many ways just a judgement call that I can imagine a roomful of engineers arguing over it until all but one drops from exhaustion, then he gets to make the choice.
  • My previous RV had a built-in ONAN with a bonded NEUTRAL/GROUND. My current RV is a trailer without a generator. If DW decides I need a generator, I will get a Honda EU2000i and an EasyStart soft starter. Since I have a Progressive Industries EMS-HW30C, I will also make a bonding plug.

    SoundGuy wrote:
    The OP's Champ inverter genset doesn't have an "open ground" but rather a floating neutral that his PI EMS interprets as an open ground. Simply adding a G-N bond is safe and will solve this issue.

    Floating NEUTRAL is the correct term, but OPEN GROUND is what the EMS reports, so that is a commonly used term.

    time2roll wrote:
    Or just use the bypass. If generator voltage is an issue it will shut down from overload before any issues to the RV happen.

    Just using the bypass switch will work, but it defeats a LOT of the protections of the EMS unit. The bonding plug is so cheap and easy, there is absolutely NO rationale for defeating those protections. Generators do fail on occasion.
  • rjxj wrote:
    Normal for most generators to be open ground.

    Modern generators (<10-20 years old), yes. Older ones were bonded.
  • rjxj wrote:
    Normal for most generators to be open ground.


    theoldwizard1 wrote:
    Modern generators (<10-20 years old), yes. Older ones were bonded.


    Neither of these generalized statements are correct, as IAMICHABOD's own example illustrates - his particular Generac is an inverter suitcase style of genset which the manufacturer has chosen to offer with a G-N bonded output ... most other inverter style gensets (Honda, Yamaha, Champion) are not G-N bonded. Each manufacturer has their own preference as to what would be the most appropriate wiring scheme for the greatest number of consumers. The only reason "older" gensets would have been bonded is that most decades ago were open frame, construction type of gensets which traditionally have been G-N bonded.

    It would be more accurate to say that most inverter genset's sold today are wired with a floating neutral output while most open frame, construction types of gensets are still wired with a G-N bond. Regardless, if you're feeding the trailer directly either wiring scheme will work just fine but if you're using an EMS between the genset and the trailer the genset output needs to be G-N bonded, whether wired as such by the manufacturer or forced by adding your own G-N bonding plug.
  • ONE of the very reasons that I went with the Generac IQ200 for my needs,I knew from it's specs that is was G-N bonded which would work well with my PI EMS 30 HW 30C,unlike the others,in fact the warranty would be voided if used with a Yamaha
  • The PI warranty disclaimer has absolutely nothing whatsoever to do with a neutral-ground bond or the lack of one.

    I believe most all portable generators under 5 kW these days (whether open frame or not, or inverter or not) do not bond the ground and neutral conductors as OSHA rules permit their use in this configuration without GFCIs. Perhaps this is only applicable to 120V generators rather than 120/240V split phase generators; I don't feel like trying to parse through the OSHA requirements. Many generators this small would probably not be 120/240V split phase anyhow.
  • IAMICHABOD wrote:
    ONE of the very reasons that I went with the Generac IQ200 for my needs,I knew from it's specs that is was G-N bonded which would work well with my PI EMS 30 HW 30C,unlike the others,in fact the warranty would be voided if used with a Yamaha


    Which may no longer be an issue. Progressive Industries' Yamaha disclaimer refers only to the original EF2000iS, no mention is made of the new and current Yamaha EF2000iSv2 which may possibly not have the same issues which concerned Progressive about the EF2000iS. It would be helpful if Progressive would provide an update in this regard to their disclaimer.

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