Inverter earthing (grounding)

[Tired sparky]

Being an electrician (UK) I understand earthing and why we do it on our mains AC systems. But I’m coming up short on why we have to earth an inverter fed from a battery bank?
The reason we earth electrical appliances is to provide a low resistance path for any fault current to travel back to the source transformer and operate the protective device or fuse. If we didn’t then the fault current might choose its path through us and into the ground to complete its journey.
But with an inverter that is isolated from the ground why would we want to introduce a potential fault current path by earthing it? If a faulty appliance is plugged in and the metal case becomes live why would we want any possible fault current going through us, into the ground, up the earthing spike and wire and back to the inverter?
If I plugged in a cable to my 230 v AC inverter and held the bare live wire standing in bare feet on the wet lawn nothing would happen. But earth that same inverter and now I’m one dead old electrician as the fault current has a path through me back to the source that wasn’t there until I earthed the damn thing??

[Sunking]

Being an electrician (UK) I understand earthing and why we do it on our mains AC systems.

No you do not understand, good for the public you retired.

The reason we earth electrical appliances is to provide a low resistance path for any fault current to travel back to the source transformer and operate the protective device or fuse.

BS you don't know what you are talking about. Earth has nothing to do with clearing a fault.

You Earth or Ground your electrical system to:
Provide a planned discharge path for lightning and utility distribution high voltages
Provide voltage-free touch potential during normal operations and minimize touch potential in the event of a fault.
Provides discharge path for static electricity.
Shorts the capacitance out between circuit conducts

All electrical codes, even UK, forbid using the earth as a fault or current path. Only utilities and God are allowed to use earth as a conductor.

[Tired sparky]

Why are you so rude????

[Tired sparky]

And it’s you who is talking BS!!!! You are getting equipotential BONDING and earthing mixed up. I’m in the UK so don’t try to push your American theory on me.

[Tired sparky]

So tell me, if it’s forbidden to use the earth as a current path how do your circuit breakers work on a live to earth fault eh? If it’s forbidden why is there earth wires in all our cables? Earthing here means providing an earth to all exposed conductive parts. Bonding is providing an earth to all extraneous conductive parts. I’m not talking about bonding and lightning protection etc, I’m talking EARTHING appliances.

[Tired sparky]

So if you had bothered to read my query instead of jumping to false conclusions and belittling me you would have seen I was talking about earthing an inverter, i.e attaching a wire from earth to the inverter and turning an IT system into a TN-S system—these are two different British utility electrical supply arrangements but you will no doubt already know that won’t you.

I was in no way talking about using the ground/earth/soil/mud/the thing you walk on and dogs bury bones in as a fault current path, as, and you did indeed get this bit right, only the utility companies can use that.

Again, please tell me since you are so well versed in Earthing arrangements and especially UK earthing regulations how, and I quote you here ; ‘earth has nothing to do with clearing a fault’?

Maybe, seeing as people from all over the world use this forum and have differing ways, maybe ask for clarification if you think they are misinformed instead of being a self righteous prick?

[DanS26]

We need remedial education on both sides of the pond for “earth” “ground” and “dirt”. The NEC could have cleared up things decades ago but nooooooo………….

[DanS26]

Just think of the wasted time and confusion by everyone involved in electrical systems because of the double meanings of the same word or words.

[sdold]

So tell me, if it’s forbidden to use the earth as a current path how do your circuit breakers work on a live to earth fault eh?

If by "earth" you mean the rod in the dirt, it isn't used as a current path for fault current on the service side because the resistance of the rod in the soil can be too high to allow enough current to open a breaker. A more direct connection is needed, which is the third wire that connects the equipment chassis to the neutral back at the service panel (the green wire in Sunking's diagram above).

[Tired sparky]

Sdold, here in the UK that green wire is generically called the ‘earth’ but properly known as the CPC or circuit protective conductor. And yes here in TT systems where the live and and Neutral come in overhead wires and the main Earth at the ‘service’ is connected to a copper rod in the ground (dirt) we use 30mA RCD’s (residual current device) to break live-earth faults.

[Tired sparky]

The confusion arose because ‘earth’ or earthing means different things to Sunking and myself.

[Tired sparky]

DanS26, I know right!! I can understand a person across the pond getting confused by the terms I’m using not fitting with their understanding of the issue. But to then demean that person and call BS and say it’s a good job I’m retired, instead of clarifying the misunderstanding is being oh what is that term in America….. ah yes, being a JERK!!

[SunEagle]

Why are you so rude????

Some people feel that Sunking is rude but based on what I know of him he comes across that way to get someone's attention if they are trying to do something electrical that can get them hurt.

Oh by the way he has been on the board of the NEC so I feel he knows his stuff which may be different in other countries based on our language differences but he will try to get someone going in the safe direction..

[Tired sparky]

I had to google the NEC as I had never heard of them! Here in the UK the NEC is the National Exhibition Centre where we go to look at cars, bikes, tool shows etc,.. Another term that has two very different meanings lol.

[SunEagle]

I had to google the NEC as I had never heard of them! Here in the UK the NEC is the National Exhibition Centre where we go to look at cars, bikes, tool shows etc,.. Another term that has two very different meanings lol.

I am afraid there are a number of words and expressions that are different. All I can say is find out what your local electrical code requires and follow those rules. Just be careful and do what is safe.