SOLVED: Different voltages on L1 & L2 in Landmark when using Honda EU7000IS Inverter

[westro]

Ok, so before any suggestions that my EU700IS Inverter is faulty... Let's establish some background.
My Honda is performing correctly, It has 125 volts on L1 and L2, measured with digital mm and shows 250 volts between L1 & L2 so the two lines are out of phase as expected.
This EU7000IS has been powering a 2013 Keystone Montana 3582RL, 15K+13.5K+everything else flawlessly until 3 weeks ago with amps to spare, nothing has changed with the EU7000IS.
Checked all my voltages again at the supply end of my 50A extension cables and again voltage is correct and stable.

Purchased a 2018 Landmark Newport... First trip out to a campsite providing 50A service, and all is well. Precision Circuits Inc Display panel indicates no problems.
Shows 118 volts on L1, 119 volts on L2 on the Precision Circuits display panel with no errors. Ran ACs + everything else with no problem.

The following week we go to a dry campsite, something we did all the time with the Montana, probably 8 or 10 times each year.. and had done two weeks prior.
Plug up my cables, plug in the shore cord to my 50A cable, fire up the Honda EU7000IS, then go look at the PCI display panel.
It says 50A service on the home display... but...and here comes the but.
Its showing L1 at 107 volts, L2 at 140 volts, and it says Wiring Status Error on the next display screen... What???
Thinking that cannot be since I checked the Honda output, we did use it but started to experience overloads at the Honda, so kept all load to a minimum. Definitely something wrong.

Week after that back to a state park with 50A service and all is well, PCI display shows no errors again on shore power.
Anyone have any idea what is going on here, I think dealer is clueless but will get it back to them to see.
How is it possible for the voltage to increase on one leg and drop on the other leg while using my Honda... which stays at 125V on each leg?

 

[danemayer]

Re: Why different voltages on L1 & L2 in Landmark when using Honda EU7000IS Inverter

A loose neutral connection will do exactly what you're describing. There's a presentation on Lost Neutral in this folder. Depending on how you're connecting to the generator, a loose neutral could be in any of several locations.

Another consideration is that the built-in surge protector (which has other functions) in your transfer switch is expecting a generator where the neutral and ground are bonded. Some generators have that. Others need it. You can read about that here.

 

[dave10a]

Re: Why different voltages on L1 & L2 in Landmark when using Honda EU7000IS Inverter

As mentioned neutral bonding is the problem. Generators built for RV's do not have neutral and ground bonded at the generator. Generators built for contractors have neutral and ground bonded at the generator.

 

[CDN]

Re: Why different voltages on L1 & L2 in Landmark when using Honda EU7000IS Inverter

Wire up a standard 15 plug with Neutral and Ground tied together. I carry one for my powerhouse. I have resisted doing the bonding inside the generator for safety issues if the generator is sold sometime.

 

[westro]

Re: Why different voltages on L1 & L2 in Landmark when using Honda EU7000IS Inverter

Great information folks, did not dawn on me that these Honda EU inverters (or others) have unbonded G-N.
Never occured to me, with our last 2 Keystone Fifth wheels having no Transfer switches or Voltage Monitors on-board.
Inverter worked flawlessly on those, but they had no on-board generator prep wiring.

I'm off to test for that issue and work up a G-N bonding plug for it.
Cannot tell you how frustrated I would be if my $4000 Inverter would not be able to power this Heartland Landmark.

 

[porthole]

Re: Why different voltages on L1 & L2 in Landmark when using Honda EU7000IS Inverter

Great information folks, did not dawn on me that these Honda EU inverters (or others) have unbonded G-N.
Never occured to me, with our last 2 Keystone Fifth wheels having no Transfer switches or Voltage Monitors on-board.
Inverter worked flawlessly on those, but they had no on-board generator prep wiring.

I'm off to test for that issue and work up a G-N bonding plug for it.
Cannot tell you how frustrated I would be if my $4000 Inverter would not be able to power this Heartland Landmark.

The power management system will not allow power through if there is an open neutral-ground bond, which is how the Honda inverter gens are wired.
The PMS sees it as an error or fault.
The neutral ground plug will allow the PMS to pass power.

Your problem seems to be something different and the first place I would look before you get to far ahead are the connections in the transfer switch. As Dan mentioned, look for neutral connections not being tight.

At 140 volts on one leg, the PMS should be disconnecting you anyway for an over voltage issue.

- - - Updated - - -

Something else you could try is using a 50 to 30 amp adapter and see how the readings are.

 

[westro]

Re: Why different voltages on L1 & L2 in Landmark when using Honda EU7000IS Inverter

The power management system will not allow power through if there is an open neutral-ground bond, which is how the Honda inverter gens are wired.
The PMS sees it as an error or fault.
The neutral ground plug will allow the PMS to pass power.

Your problem seems to be something different and the first place I would look before you get to far ahead are the connections in the transfer switch. As Dan mentioned, look for neutral connections not being tight.

At 140 volts on one leg, the PMS should be disconnecting you anyway for an over voltage issue.

- - - Updated - - -

Something else you could try is using a 50 to 30 amp adapter and see how the readings are.

Ok, Thanks! Good thought on the 30 amp adapter... I was going to try that today from my 30A NEMA plug on the Honda, rather than from its 120/240 plug to see what it reads on the PCI panel.
Will hunt down the transfer switch as well to check it.

 

[westro]

Re: Why different voltages on L1 & L2 in Landmark when using Honda EU7000IS Inverter

Ok, Thanks! Good thought on the 30 amp adapter... I was going to try that today from my 30A NEMA plug on the Honda, rather than from its 120/240 plug to see what it reads on the PCI panel.
Will hunt down the transfer switch as well to check it.

OK, so now I have made some progress:

Verified that the Honda EU7000IS is not Grd-Neutral bonded, per Honda documentation, so worked up a G-N bonding plug to insert into one of its 20A GFCI duplexes. Tested that I now had the G-N bonding as needed at the Generator.

Started hunting for floating neutral connections in the coach, Located the Transfer Switch (TRC Model 41260) and checked/tightened all the connections in it. Nothing I would really call loose but took about a 1/4 to 1/2 turn on a couple of them to be certain they were really tight. Checked all the ground wire connections at the Transfer switch and the converter right beside it. Took the cover off the Precision Circuits sub panel and checked/tightened all neutral & ground buss bar connections and every circuit breaker connection.

When I was done with all that (plus cleaning out all the debris these bozos leave, really? why???). Blew out the transfer switch, found a broken plastic ear (not important) off one of the contactors, and noticed the cover (which was not attached, just sitting on top) had one of the little metal ears missing that locate it in place... Hmmm, now where did that go? Found it laying next to one of the pc boards in the switch and retrieved it... Just what I need, a metal piece bouncing around in the transfer switch with circuit boards.

So on to testing running the coach off the Honda 7000... Started with all coach breakers off, shore cord plugged into the Honda on 120/240V cable, and started up the Honda. Checked that the transfer switch contactor closed on the shore cord input side, and that I had 125VAC on the input/output side legs, which matched the Honda's output... all good.
Brought the Main breaker in the coach up with no other loads, and checked L1/L2 again at the Main breaker, 125VAC as expected on each leg. Brought up the remainder of the PCI panel breakers and checked the PCI display, says 50A service, L1=125v and 2amps, L2=125v and 1amp, and Wiring Status OK... Exactly what I hoped to see.

Cut in the first one of the three 15K ACs on L1 leg, got a short chatter out of the transfer switch, didn't really surprise me with all the debris I blew out of it, pretty much the same thing that happens with our house furnace the first time the heat comes on in the winter. It settled down and L1 showed 18amps after the AC kicked in. Brought up the 2nd 15K AC on L2 and it came up and ran with no further chatter from the transfer contactor. So now I'm seeing L1 at 18amps, L2 at 14 amps, and everything OK. Went and checked the Honda, it showed 3270 watts and was purring away like it usually does. After letting everything run for a while, I gave the 3rd 15K AC a try, knowing I would overload the generator, but wanted to see what happened. Resulted in tripping the GFCI duplex on the Honda, which took the G-N bond away and of course voltages went away and the transfer switch complained loudly... Ok, so 2 15K ACs while dry camping on our Honda 7000 is all we can reasonably run with some margin to spare for other stuff. That pretty much matches up the the Honda 7000 specs, which state 22.9amps (45.9 total) running per leg on the 120/240 setting.

So wanted to again Thank those of you that helped me out on this, educating me, and pointing out some great information. I will no doubt test again on the Honda's 30amp service, but expect that it will be fine. I'm feeling a lot better about heading to Bristol Motor Speedway next week and having this thing working at the correct voltages. Its Bristol, Baby!

 

[Nabo]

Congratulations on conquering the mystery of the generator. We also are heading to Bristol arriving on Sunday the 12th over at OTBR LLC campground on Old Thomas Bridge Rd. We gave up using gennies in that this cg has 50 amp/water services. Come by and see us.

 

[westro]

Congratulations on conquering the mystery of the generator. We also are heading to Bristol arriving on Sunday the 12th over at OTBR LLC campground on Old Thomas Bridge Rd. We gave up using gennies in that this cg has 50 amp/water services. Come by and see us.

We have been at the Landing Campground on 394 for the past 8 years... Was the OTBR LLC Campground previously named something else? There are a few Campgrounds on Old Thomas Brifge Rd. We'll have to drive over there and see where that one is while down there.

Thx,
Bob