Running a GFCI outlet from inverter.

[CoolWill]

So all good, right?

Only if you're OK spending $25 on a receptacle that gives you a false sense of security. The whole point of this thread was about adding a GFCI in a van. I contend that unless the inverter can have a grounded neutral (unlikely for many automotive types), the GFCI does nothing more.

This is more about understanding the theory of operation than anything. You certainly can use a GFCI, but in that situation it's just a very expensive receptacle.

 

[CoolWill]

Ok.

So let's say a portable generator, not touching the ground etc.

I can strip the end of an extension cord and expose the hot (black wire) and grab it and I won't get shocked so long as the generator is electrically isolated from earth?

Or let's say, I'm wearing rubber shoes?

If you come over to me when I'm holding it, put positive from the fluke meter on my body and the negative on the neutral my body will be at 120 volts but no shocky?

There will be no shocky until the black meter probe touches the neutral. There will be a small current because the meter doesn't have infinite impedance.

 

[Checkthisout]

There will be no shocky until the black meter probe touches the neutral. There will be a small current because the meter doesn't have infinite impedance.

Ok. Would you be willing to do thus?

a/c reverses direction 60 times a second and the body has capacitance, especially compared to a small bird.
?

 

[CoolWill]

Ok. Would you be willing to do thus?

a/c reverses direction 60 times a second and the body has capacitance, especially compared to a small bird.
?

Not only would I do it, have done it, I can tell you the math about why you're wrong. Even if we ignore the resistance of human skin, the capacitive reactance is still over 25 megohms, assuming a capacitance of 100 pF. At that impedance a current of only 5 MICROAMPS will flow. Well below the threshold of human sensation. Use this handy web calculator to input values for an RC circuit

https://www.redcrab-software.com/en/Calculator/Electrics/RC-Series-CircuitSure

Using 20 k ohms for the resistance and 100 pF for the capacitance, the calculator says 4.5 microamps at 120 volts and 60 Hz. And the bird has perhaps 20 pF capacitance, less resistance and higher voltage. I used 7500 volts as the input. And over 10 times the current is flowing in the bird, 57 uA. More current flows through the bird!

 

[Quattrohead]

How do you think linesmen work on those 50kv lines ? They only touch 1 at a time.
So yes, you can touch a very high voltage and not feel it.....until you touch something else as well.
GFCI work on balance between the 2 conductors.

 

[CoolWill]

Double post...??

 

[WNCGUY]

GFCI's are designed to work with or without a ground.


Does your inverter have GFCI protection built-in?

The 3 outlets on the inverter do not have the typical GFCI reset button and there is no mention in the manual of CFCI.

 

[Checkthisout]

Not only would I do it, have done it, I can tell you the math about why you're wrong. Even if we ignore the resistance of human skin, the capacitive reactance is still over 25 megohms, assuming a capacitance of 100 pF. At that impedance a current of only 5 MICROAMPS will flow. Well below the threshold of human sensation. Use this handy web calculator to input values for an RC circuit

https://www.redcrab-software.com/en/Calculator/Electrics/RC-Series-CircuitSure

Using 20 k ohms for the resistance and 100 pF for the capacitance, the calculator says 4.5 microamps at 120 volts and 60 Hz. And the bird has perhaps 20 pF capacitance, less resistance and higher voltage. I used 7500 volts as the input. And over 10 times the current is flowing in the bird, 57 uA. More current flows through the bird!

I mean I understand that concept of an incomplete circuit and have seen "powerline walkers" and all that but I have just had the shit shocked out of me so many times by the single hot that I can count.

Even with shoes on etc. I assumed it was the capacitance of my body.

 

[WNCGUY]

The guy is in a van, the van metal is the 'ground'.
If the inverter is a low cost unit there is a possibility it cannot be neutral to PE bonded, the inverter liturature should state that the bond exists or that the unit can be modified to create the bond, or that its not allowed.
If a GFCI cannot be installed, ùsing any extension cable or distributed sockets is not advised, only connect one appliance ar a time directry Into the inverter output sockets.
Mike

@mikefitz and others

Inverter is, GoWise Power PS1005-NP. I don't have the electrical knowledge to determine if the inverter is or can be PE bonded, if a bond exists, modified or not allowed.
Inverter manual link.
https://cdn.shopify.com/s/files/1/0...001-NP_PS1006-NP_user-manual.pdf?v=1660061193

Perhaps I made this more difficult than needed when I asked about adding a GFCI. Would I be safe to simply as a 3 prong plug to 14/3 AWG Flat Triplex Marine Grade Wire (basically making an extension cord to the outlet box)?

 

[Checkthisout]

@mikefitz and others

Inverter is, GoWise Power PS1005-NP. I don't have the electrical knowledge to determine if the inverter is or can be PE bonded, if a bond exists, modified or not allowed.
Inverter manual link.
https://cdn.shopify.com/s/files/1/0...001-NP_PS1006-NP_user-manual.pdf?v=1660061193

Perhaps I made this more difficult than needed when I asked about adding a GFCI. Would I be safe to simply as a 3 prong plug to 14/3 AWG Flat Triplex Marine Grade Wire (basically making an extension cord to the outlet box)?

Yes, that would be fine.

 

[Zapper77]

The 3 outlets on the inverter do not have the typical GFCI reset button and there is no mention in the manual of CFCI.

My Renogy 1K-3K inverters from 2020 have GFCI protection. If the GFCI is tripped the only way to reset it is to power off the inverter.

 

[CoolWill]

I mean I understand that concept of an incomplete circuit and have seen "powerline walkers" and all that but I have just had the shit shocked out of me so many times by the single hot that I can count.

Even with shoes on etc. I assumed it was the capacitance of my body.

No way. It's always some part of you is grounded. I have been shocked because I was touching a ceiling grid that is incidentally grounded by the fluorescent lights. Or a water pipe. If you stand on a dry pallet with nothing around and touch a hot 120 V conductor, you won't feel a thing. In fact, a non contact voltage tester in you other hand will chirp since you are now at 120 volts.

 

[TacomaJoe]

@mikefitz and others

Inverter is, GoWise Power PS1005-NP. I don't have the electrical knowledge to determine if the inverter is or can be PE bonded, if a bond exists, modified or not allowed.
Inverter manual link.
https://cdn.shopify.com/s/files/1/0...001-NP_PS1006-NP_user-manual.pdf?v=1660061193

Perhaps I made this more difficult than needed when I asked about adding a GFCI. Would I be safe to simply as a 3 prong plug to 14/3 AWG Flat Triplex Marine Grade Wire (basically making an extension cord to the outlet box)?

I have the GoWISE 2000W in my trailer and just completed a couple of tests. The neutral and ground are isolated but can be bonded. Without the bond, a lamp between the hot and ground will not trip my GFCI (no current flows).

 

[Hedges]

Neutral to PE bond is ended for a GFCI to operate.

GFCI's are designed to work with or without a ground.

In my experience, some GFCI outlets require a ground to reset, and some do not.
GFCI is allowed as a way to put 3-prong outlet in a 2-wire circuit.
It should be used for kitchen/bath/outdoors so you don't get a shock to plumbing or earth. Regardless of whether ground wire is available.

I installed Eaton GFCI, found it wouldn't reset, instructions said it checks L/N connections.

I replaced with Leviton and it did work without ground.

A GFCI will not operate if no current flows to ground.

If no ground or neutral exist in your scenario, then you won't get shocked.

If no path to earth from inverter except one, you the person, you won't get a shock and GFCI will not trip.

If there is so much as capacitance to earth, you can get a shock. People have been experiencing that with PV panel frames. The PV wires carried about 60Vrms AC. Bonding frames to inverter with a ground wire fixed that.

If your inverter on a van powers one 3-prong appliance that is lying on the ground (e.g. electric tool with metal case) and you touch Line or the case of an appliance with internal fault, you get a shock. Cheap +/-60V portable inverters, I think shock between faulty appliance and vehicle chassis (or earth if foliage touches vehicle) would be a possibility.

The GFCI won't trip unless it detects imbalance between L and N of 0.005A or more, such as through your body. Then it will trip and protect you.

GFCI won't protect you if you grab line with one hand and neutral with the other. So long as you only touch case of appliances, don't grab bare wires, you should be protected. (Unless you're as creative as me, you could wire multiple devices to make a shock hazard anyway. But that's another story ...)

 

[Zapper77]

@mikefitz and others

Inverter is, GoWise Power PS1005-NP. I don't have the electrical knowledge to determine if the inverter is or can be PE bonded, if a bond exists, modified or not allowed.
Inverter manual link.
https://cdn.shopify.com/s/files/1/0...001-NP_PS1006-NP_user-manual.pdf?v=1660061193

Perhaps I made this more difficult than needed when I asked about adding a GFCI. Would I be safe to simply as a 3 prong plug to 14/3 AWG Flat Triplex Marine Grade Wire (basically making an extension cord to the outlet box)?

I wonder what protection this is.

 

[Checkthisout]

No way. It's always some part of you is grounded. I have been shocked because I was touching a ceiling grid that is incidentally grounded by the fluorescent lights. Or a water pipe. If you stand on a dry pallet with nothing around and touch a hot 120 V conductor, you won't feel a thing. In fact, a non contact voltage tester in you other hand will chirp since you are now at 120 volts.

I'm not sure I trust this. ?

I'll take your word for it.

 

[TacomaJoe]

I wonder what protection this is.
View attachment 157943

That protects the inverter but doesn't protect you. You are not a short or an overload. The inverter is happy pushing 10A out but you will not be so happy.

 

[Johno1066]

Look if you really want the protection of a GFI, plug two conductors into the inverter with the other end going to the GFI. Get a ground wire connected to your RV's frame and connect it to the ground of the GFI. Connect the neutral and ground to the input terminals then just put a bridge wire between the ground and the neural, what you are then doing is grounding your own neutral and if there is any leak to the vehicles frame with any apliance you plug into that GFI it will trip and you will be safe. The Neutral is the larger of the two plug contacts and should be a white conductor.

 

[CoolWill]

I have the GoWISE 2000W in my trailer and just completed a couple of tests. The neutral and ground are isolated but can be bonded. Without the bond, a lamp between the hot and ground will not trip my GFCI (no current flows).

?

I'm not sure I trust this. ?

I'll take your word for it.

I certainly wouldn't encourage someone to tempt fate by making a habit out of it. But I've done it and know for sure it is OK. Maybe I'll get a video soon.

 

[JRH]

Ya know, grounding discussions suck…
I have learned how to do many things in solar rather easy… balancing batts , wiring , all the Ohms suggestions( ha)….. how to earn the money to buy good stuff …how to hide the cost from the wife …even how to hook it all up to look good and run great…BUT…
Every time I think I have got a somewhat basic grip on grounding issue , everyone in the forum weighs in on “grounding“ …whatever the reason or topic , I read about 10 different well meant comments by people much smarter than me that evolve into every known possible scenario that could be an issue or a way to die or why this and why that,and start conflicting with each other and throwing out different theories and then causing me to doubt everything I have done….. it’s depressing…
At that point sometimes I walk outside and look at my system and say out loud ….

“ Obviously, I have not the slightest idea what I am doing… I’m Gona get electrocuted”

I can’t be the only one…

I don’t think I have ever encountered a topic other than marriage , that is so contradictory, ambiguous and mysterious to so many.

J.