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?

[user113]

Sounds to me like you may have a wiring issue in the trainer wiring. You said you tried the vacuum in all the outlets; I wonder if you also tried the microwave outlet? I suggest you plug the vacuum into the Microwave's outlet if you haven't tried that one yet. And/or try the microwave in the other outlets, too. There might be a short between the ground and neutral in part of the trailer's wiring that only leaks sufficient current to trip the GFCI when mucho amperage is flowing.

The OP's comment on 6/30 makes the most sense. Just a matter of tracking it down now.

[Dano1955]

kellertx5er wrote:
Any electrical experts out there?

Funny question- EVERYONE here is an electrical expert, right?

X@..I was gonna say....:D

[Njmurvin]

DogTrainer wrote:
Make is easier and then pick it apart.
GFI only trip when two much current is being pulled out of plug as in current which equates to watts P=ei or power is equal to voltage times current OR

your device has a ground issue directly to the plug. plugged into an inverter can bypass or isolate the ground issue as the inverter will mask it.

I think there's some strange grounding issue. There's no way the vacuum + parasitic draws are exceeding the inverter's capacity (2000 watts peak and 1800 continuous). Besides, such an overload would exhibit different behavior with error codes on the display and an alarm.

It's most likely something in the grounding BETWEEN the trailer and the vacuum because the vacuum works fine from the inverter as long as the trailer is not also plugged into the inverter.

[kellertx5er]

Any electrical experts out there?

Funny question- EVERYONE here is an electrical expert, right?

[DogTrainer]

Make is easier and then pick it apart.
GFI only trip when two much current is being pulled out of plug as in current which equates to watts P=ei or power is equal to voltage times current OR

your device has a ground issue directly to the plug. plugged into an inverter can bypass or isolate the ground issue as the inverter will mask it.

[justafordguy]

No need to vacuum while the power is out anyway. 😉

[Njmurvin]

Roller4Tan wrote:
Just a thought...Is the vac plug polarized(one lug wider than the other)? If not, does it trip the GCFI in either orientation in the outlet? Assuming it's a two pronged plug.

I haven't tried reversing the plug because it does have the oversized lug on one side and the receptacles won't accept it reversed. I can build a short extension that will do this but I have to wait until July when I bring the trailer back out of storage.

Thankfully, only this vacuum has this issue so far - which I can certainly live with.

[Roller4Tan]

Just a thought...Is the vac plug polarized(one lug wider than the other)? If not, does it trip the GCFI in either orientation in the outlet? Assuming it's a two pronged plug.

[ScottG]

Njmurvin wrote:

ScottG wrote:
A coil like in a motor, can trick a sensitive GFCI into thinking there's a ground fault. This is due to the rule of "ELI", where voltage always leads current through an inductor (or coil). Because of this, there is current flowing that doesn't follow the timing the GFCI expects. This is the differential current the rep spoke of.
This was a serious problem in the early days of GFCI's but they have generally been updated to solve the problem.

This sounds like a definite possibility. If so then not all motors act the same way. My ceiling fan works great as does my small shop vac. For now I'm going to have to assume it's something specific to the motor or coil in this vacuum unless and until I discover another a problem device.

The effect on a GFCI is worse with a bigger motor and higher start up current.
When they started requiring GFCI in garages, larger power tools like skill saw's wold trip them constantly. They quickly changed something in them to alleviate the problem.
Your fan is a much lighter motor than the vac.

[Njmurvin]

ScottG wrote:
A coil like in a motor, can trick a sensitive GFCI into thinking there's a ground fault. This is due to the rule of "ELI", where voltage always leads current through an inductor (or coil). Because of this, there is current flowing that doesn't follow the timing the GFCI expects. This is the differential current the rep spoke of.
This was a serious problem in the early days of GFCI's but they have generally been updated to solve the problem.

This sounds like a definite possibility. If so then not all motors act the same way. My ceiling fan works great as does my small shop vac. For now I'm going to have to assume it's something specific to the motor or coil in this vacuum unless and until I discover another a problem device.

[Njmurvin]

Fridge and water heater are set to propane when running and microwave breaker turned off. But all were completely off during testing except when I used the microwave for a load test.

[Ed9824v]

time2roll wrote:
Assuming the vacuum has a ground plug... can you use a two prong extension to unground the vacuum?
I am thinking the motor induces a ground current in the RV when operating.
Then try plugging the RV into the inverter with a two prong plug.

Have you tried another vacuum?

2000w inverter should power anything that plugs into a regular outlet.

Do you have the fridge and water heat set to propane only?

good question on the water heater on electric, that thing can be 1000 to 15oo watts alone. I has issues at one campsite tripping there breaker and turns out the electric water heat was just too much for this maybe weak breaker

[time2roll]

Assuming the vacuum has a ground plug... can you use a two prong extension to unground the vacuum?
I am thinking the motor induces a ground current in the RV when operating.
Then try plugging the RV into the inverter with a two prong plug.

Have you tried another vacuum?

2000w inverter should power anything that plugs into a regular outlet.

Do you have the fridge and water heat set to propane only?

[ScottG]

A coil like in a motor, can trick a sensitive GFCI into thinking there's a ground fault. This is due to the rule of "ELI", where voltage always leads current through an inductor (or coil). Because of this, there is current flowing that doesn't follow the timing the GFCI expects. This is the differential current the rep spoke of.
This was a serious problem in the early days of GFCI's but they have generally been updated to solve the problem.