Any electrical experts out there?

[Njmurvin]

I have strange one. I have installed a Xantrex ProWatt 2000 pure sine wave inverter. I plug my shore cord into the inverter and turn off my trailer's converter/charger. All outlets and 110V devices work great running off the inverter. I have tested the microwave, ceiling fan and several plug in appliances (e.g. Bose charger, small hair drier, etc.) and all of those work perfectly.

Here's where things get interesting. I have a small Shark vacuum cleaner that's rated at 1000 watts. If I plug into any outlet in the trailer, the GFI on the inverter trips. If I plug it directly into the inverter WHILE THE TRAILER IS ALSO STILL PLUGGED INTO THE INVERTER, the GFI on the inverter trips. However, if I unplug the trailer from the inverter and then plug the Shark into the inverter by itself, it works fine. There are no other active loads on in the trailer during this test and there is no error displayed on the Xantrex inverter LED display. It also works fine if the trailer is plugged into real shore power.

I suspect this points to some sort of grounding issue. The inverter's negative side goes to a shunt where all the negative loads in the trailer go (essentially to the negative side of the battery bank). The inverter's chassis ground lug goes to the trailer frame (per installation instructions).

So far, this is the only electrical device that does this. Any ideas why this is happening?

[Njmurvin]

I reached out to Xantrex. The responder mentioned something about the possibility that the vacuum is creating "differential current". I googled it and it was over my head. He recommended an inverter that is meant to be hard wired (i.e. some of their more expensive models). That's nice. But, I have $400 invested in this one and I'm not prepared to dump it in favor of an upgrade just so I can run this particular vacuum. I'm just concerned that I may run into other devices in the future with similar behavior.

The vacuum has a 2 prong plug (also suspicious) but other devices I have plugged in also have 2 prong plugs. I will try the extension cord test but the trailer is now stored away and I don't have access to the storage bay where the inverter is located. I can plug an extension into one of the trailer's AC outlets and try it that way. I have a remote switch for the inverter to turn it on and off from inside the trailer.

[neschultz]

Ask Xantrex if they have any ideas. I suspect some sort of EMI/EMC issue.

I'm curious: 1) does the Shark have a two wire or 3 wire AC cord? 2) If you plug the shark into the inverter via a long extension cord with the trailer connected and get far away from the trailer does it still do it?

[Njmurvin]

The microwave is rated at 1350 watts and I ran that for a full minute. It was drawing about 120 amps from my batteries according to my Trimetric monitor. That sounds about right (12 x 120 = 1440).

I'm leaning toward something hinky with the vacuum. But, it's still odd that even it works when the rest of the trailer is unplugged.

[Ed9824v]

Njmurvin wrote:
Newman, I thought of that (too many watts). But, the inverter has error codes and alarms for that. Besides, the vacuum is only rated 1000 watts and the inverter is rated at 2000 watts (1800 sustained). Everything else in the trailer is off (except parasitic loads). I have another vacuum (small shop vac) that works fine. So far, it's only this Shark vac that seems to be a problem.

Rjxj, I assume you mean the DC cables powering the inverter. They are huge (4/0) and maybe 3 or 4 feet max.

I am still thinking it may be a grounding issue but am curious why this vacuum is the only device (so far) that behaves like this.

I would like to try another 1000 watt load, there may be an insulation break down in the vacuum that is tripping the GFI.

[Njmurvin]

Newman, I thought of that (too many watts). But, the inverter has error codes and alarms for that. Besides, the vacuum is only rated 1000 watts and the inverter is rated at 2000 watts (1800 sustained). Everything else in the trailer is off (except parasitic loads). I have another vacuum (small shop vac) that works fine. So far, it's only this Shark vac that seems to be a problem.

Rjxj, I assume you mean the DC cables powering the inverter. They are huge (4/0) and maybe 3 or 4 feet max.

I am still thinking it may be a grounding issue but am curious why this vacuum is the only device (so far) that behaves like this.

[Ed9824v]

newman fulltimer wrote:
its simple to many watts

there
might just be too much watts. Can you check the wattage using b4 you plug in the extra load. and the starting watts in greater then the running wattage. not expert and not sure why it shows up with it tripping the GFI?

[azrving]

What size cables and how long?

[newman_fulltime]

its simple to many watts