Help Open Ground Problem

redneck51

Advanced Member
Joined
Apr 25, 2021
Posts
35
I just traded in my 2017 North Point for a 2020 Pinnacle, it has a residential fridge, which means I now have a inverter and converter, so to my dismay my cummins p4500i generator which works fine on my North Point, but on the Pinnacle there's a black box that's the transfer switch, with the gen running there's a red light on the box that says "Open Ground" which means this gen won't won't work on the Pinnacle.
The volt reading hot to the common reads 125v, but from the hot or common side to the ground is only 61v. I understand it should also be 125v.
Is my generator malfunctioning? North Point doesn't have a problem. But open ground with the Pinnacle?
 
Those newer "smart" transfer switches can be a royal pain. My son had one in his rig and we were camped at a campground that had a ground that wasn't perfect. Not open, just some voltage above zero. His transfer switch wouldn't allow shore power through. No way around it.

The park electrician came out and replaced the entire outlet panel but that didn't help. They said they have had problems with newer rigs and those transfer switches. Probably the only true fix would to be fix the entire campground's electrical system.

My son ended up installing a non-smart switch as he has an external regulator box that will detect open grounds but I think it still allows voltage to pass.

I don't think a poor ground should prevent you from camping. Sure, it is a nice thing to know but not stop you dead in your tracks (poor choice of words). As far as safety is concerned, an electrician would have to chime in here. I would think the rig would still be safe inside as the internal ground would be good. The only thing missing would be the earth ground which really wouldn't come in to play until you were outside.

Ok, say the ground is open. For a problem to present itself I would think there would have to be major voltage leakage into the ground system which could result in the skin having a voltage on it. Yep, that could be a problem but only if you were in contact with it and maybe a metal pipe that has a good ground or maybe laying on the ground while working on your frame.

Just my opinion but I am no expert. I continue to camp at the site with the poor ground (am going there in 3 hours) and am not concerned. Have been going there for many years and have not had a problem.
 
Having a ground connection is needed for safety reasons. As long as no appliance or any of the RV's 120v wiring gets shorted to the ground (frame, chassis, microwave cabinet, etc.), then there will be no issues though. The problem is that almost shorts are unexpected and when they occur, a serious electrical safety issue presents itself.

With all that in mind, I know on my Progessive HW (hard wired) EMS that in the case of a fault such as a bad ground, that I can use the bypass switch on the EMS control panel to allow the power to flow anyway. I suspect that other EMS's may not have a bypass switch but I would suggest that everyone should take the time to know what EMS they have (if any) and check and see if it has a bypass switch. If you are just now purchasing an EMS, I would only purchase one that did have a bypass option. ~CA
 
Thanks Frosty & Mark,
Plug in a "Neutral Grounding plug" into my generator and my problems over? With no consequences? I'll make one up tomorrow and see if it runs my Pinnacle.
But reading this forum's web talk my coach can potentially be very temperamental. If the RV park has a few volts off one way or another no power for me.
 
Thanks Frosty & Mark,
Plug in a "Neutral Grounding plug" into my generator and my problems over? With no consequences? I'll make one up tomorrow and see if it runs my Pinnacle.
But reading this forum's web talk my coach can potentially be very temperamental. If the RV park has a few volts off one way or another no power for me.

A few volts as in +or- 3 volts? If so, I would replace the EMS as it is likely defective. The range should be much wider somewhere around 104~105 to 130~132 volts. ~CA
 
Many inverter generators have no Neutral to Ground bond as you have in your shore power. As more and more monitoring systems (EMS) test for this bond, they will not allow connection. The reason for the connection is to help breakers operate during ground fault condition.
The reality is the generator will trip from overcurrent before a circuit breaker in your RV would trip from ground fault condition. The gen cannot make enough current for the breaker to operate.
 
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Many inverter generators have no Neutral to Ground bond as you have in your shore power. As more and more monitoring systems (EMS) test for this bond, they will not allow connection. The reason for the connection is to help breakers operate during ground fault condition.
The reality is the generator will trip from overcurrent before a circuit breaker in your RV would trip from ground fault condition. The gen cannot make enough current for the breaker to operate.

Perhaps I don't follow your logic, why is it a 4500 generator would be unable to trip a 15A (or even 20A) breaker if the hot shorted to the ground on a breaker protected circuit and with a neutral\ground bond at the generator? Without the bond the breaker would leave the hot current on the grounded sections (most of the metal in the RV), with the bond the (a) breaker will trip that wouldn't trip otherwise. ~CA
 
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Craig, A 4500 watt generator will be able to trip a 15, 20, or 30 amp breaker under overload. Or heat over a certain amount of time. Thus overcurrent protection. But ground fault is required to have high amps that trip magnetically a different part of a circuit breaker. Standard 120 volt breakers are rated to not explode at up to 10K amps. But it takes a higher amps than a 4500w generator can produce to trip magnetically. Over a longer period of time it should trip under overcurrent. Just not as fast.
 
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Craig, A 4500 watt generator will be able to trip a 15, 20, or 30 amp breaker under overload. Or heat over a certain amount of time. Thus overcurrent protection. But ground fault is required to have high amps that trip magnetically a different part of a circuit breaker. Standard 120 volt breakers are rated to not explode at up to 10K amps. But it takes a higher amps than a 4500w generator can produce to trip magnetically. Over a longer period of time it should trip under overcurrent. Just not as fast.

I understand your point now that you mentioned the magnetic trip aspect and I wasn't thinking about that in particular (I was thinking about the overload condition that would occur). I will add though that according to the trip curve, and an overload thermal tripping of common 15A breaker should do so in 10~40 seconds at 4500w (~250% of the breaker's rating), if the generator didn't overload sooner than that.

Also a thought to share is that while I know why most portable generators often don't bond the ground and neutral, I think they should all default to doing so for safety reasons as I would suspect most portable generator's usage will not have a N/G bond at all anywhere else, compared to a non-portable whole house backup generator.

Just a note to others, many (even if not documented) portable generators can easily be N/G bonded behind the outlet panel if one wanted to do that instead of using an adapter. Some generators I have seen document that in the owner's manual. I haven't checked my Onan 4000 to see if it is N/G bonded and my ems isn't on the generator line so I am not sure, I would expect it is though. ~CA
 
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I believe that inverter generators will trip out from overcurrent quicker than the old standard alternator gens. You got to protect the electronic pixies!
 
I'm not understanding some of this tech talk.
But are we all in agreement that the "Neutral Grounding plug" has no consequences? Good to go?
 
For the record I made my our plug took the volt meter common to groung on the generator read 61v plugged in the neutral ground plug and instantly the meter read 125v. And now it powers my Pinnacle like my follow Jaycoer's said.Thanks Friends
 

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