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Earth Rod attached to motorhome...any unforseen detrimental effects?

Solarfun4jim

Solarfun4jim

Solar seduced :-)
Joined
Sep 22, 2019
Messages
743
Location
Sunny Scotland
In a rubber tyre insulated motorhome, is there any downside to attaching an earth rod to the chassis when parked up, when using 240v ac inverter power only(no grid tie or grid earthing) ?
Is it safer with the earth rod connection or not?
 
well, if you are sure(like really sure) you will never connect to an external power source (which would include an extension cord) then its a good idea to have a real ground connection.
 
if you’re in a place you are not worrying about puncturing cables or pipes, and the soil is conducive to driving something, I don’t see why not. All the 120 volt generators I’ve used have had grounding rods, (5500 watt and below) but I’ve never seen anyone ground those. A lot of the work I did in the field with larger equipment like 400 hz, those always had grounding rods In the earth.

A few of the places I’ve lived had self help projects like sprinklers installed years or decades ago and you’ll never know exactly where those pipes are. I’ve even seen utilities install cabling where they are not supposed to to get service back up and running.

Might not be true in Scotland, but in my house with close houses, especially the front yard, there’s a lot underground.
 
I second that. I'd rather have the rubber insulation and not actually BE the grounding rod. That earth ground won't help you in some EMF inductance situation either, it could be worse. I wouldn't provide a path for electricity where not needed.
 
You already tried this in your other thread from the 3rd.

My inverter is a Victron multiplus 24/3000/70-16
Click to expand...

What about all those Victron folks on boats? Hows that grounding rod working out for them?
 
Boondock Saint said:
You already tried this in your other thread from the 3rd.



What about all those Victron folks on boats? Hows that grounding rod working out for them?
Click to expand...
@Boondock Saint

Thanks for your reply boondock saint...

I thought i had all the grounding worked out, but a qualified electrician friend has thrown a spanner in the works by insisting that i need an earth rod for RCD protection.

As regards boats, if they have a metal hull, would this not conduct through the water back to earth?

The reason i keep asking questions as im getting so much conflicting information and i'm paranoid about electricity. I need to be 100% confident my vehicle is safe, not 99.9%

See my rough earthing drawing of current setup...care to comment?earthing diagram.png
 
Last edited:
Solarfun4jim said:
using 240v ac inverter power only
Click to expand...
In the UK a permanently installed inverter feeding multiple appliances and sockets needs RCD protection to comply with regulations. This needs the inverter to be neutral earth bonded at the inverter and the protective earth's connected to van metalwork. You don't need a connection the dirt earth.
The multiplus has an internal relay that looks after the bonding when off grid, it disconnects this bond when on shore power, thus relying on the bond at the supply point as required by regulations.
Your electrical expert is wrong.

Mike
 
mikefitz said:
In the UK a permanently installed inverter feeding multiple appliances and sockets needs RCD protection to comply with regulations. This needs the inverter to be neutral earth bonded at the inverter and the protective earth's connected to van metalwork. You don't need a connection the dirt earth.
The multiplus has an internal relay that looks after the bonding when off grid, it disconnects this bond when on shore power, thus relying on the bond at the supply point as required by regulations.
Your electrical expert is wrong.

Mike
Click to expand...
@mikefitz
Thanks mike...that was my thinking. Are you are qualified electrician by any chance? Could you please point me in the direction of the relevant section within the 18th edition regulations, so that i can argue my case with my 'electrical expert' friend.

Thanks for your help.... this reassures my own point of view.
 
People get concerned about ‘too many electrical paths’ and worry about lightning and stuff and mention rubber tires…

First off the rubber tires do nothing, the vanDegraf effect does (provided your camper exterior is aluminum).
Second, a ground to “earth” has a few positives the biggest one in my mind is this: if something bad electrically happens it keeps YOU from being the path to the electrical potential/differential. The vanDegraf effect will be unaltered by a ground rod.

For function: no a ground rod is not needed.

Boats have very specific guidelines for three related things: tying the neg(-) conductors at some point; isolating the 120VAC from the hull/water; and insuring there is an isolated safety ground with shore power.
 
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Thanks for the replies folks....getting off topic when discussing boats, i feel. My comment on boats was only in relation to boondock's comment. I'd rather stay focussed on RV/motorhomes on insulated tyres.

Thanks
 
@Solarfun4jim is your vehicle stationary or will it be moving?
If its going to be moving, does your electrician think your are going to be swinging an 18 pound sledge hammer every time you park up?
Do you think you will be swinging a sledge every time?
 
That was the point of the boat wiring posts- the principles are the same (for safety and anti corrosion) minus the presence of water.

YOUR TIRES WILL NOT PROTECT YOU FROM BEING A POTENTIAL CONDUCTOR if certain things go wrong

However, having an earth ground is not required. I suppose that in my case (stationary RV) the steel foot on my steel tongue jack in contact with the ground /is/ a ground of sorts, I’ve not had a ground rod for the three years I’ve been doing this. However, my chassis and wiring are bonded with the safety ground of the 120V inverter-out and inverter earth stud, and I have a GFCI between the inverter and breaker box.

Summary: you’re probably fine, you should GFCI protect, and don’t just throw out information you perceive as irrelevant because when you drew that conclusion you did so because don’t understand the whole electrical picture.
 
12VoltInstalls said:
Summary: you’re probably fine, you should GFCI protect, and don’t just throw out information you perceive as irrelevant because when you drew that conclusion you did so because don’t understand the whole electrical picture.
Click to expand...
@12VoltInstalls probably already knows this but in case some folks don't... i translaste from English to English.

Ground Fault Circuit Interrupter ~= Residual Current Device
 
smoothJoey said:
@Solarfun4jim is your vehicle stationary or will it be moving?
If its going to be moving, does your electrician think your are going to be swinging an 18 pound sledge hammer every time you park up?
Do you think you will be swinging a sledge every time?
Click to expand...
Moving RV. He envisions a short earth rod pounded in with a hammer and soaked with water. I dont fancy the idea myself, but everyone says that i must get the system 'checked out by a qualified electrician', but having done so, i'm now getting told frequently that he is wrong in his assertions. :unsure::cry:
 
12VoltInstalls said:
People get concerned about ‘too many electrical paths’ and worry about lightning and stuff and mention rubber tires…

First off the rubber tires do nothing, the vanDegraf effect does (provided your camper exterior is aluminum).
Second, a ground to “earth” has a few positives the biggest one in my mind is this: if something bad electrically happens it keeps YOU from being the path to the electrical potential/differential. The vanDegraf effect will be unaltered by a ground rod.

For function: no a ground rod is not needed.

Boats have very specific guidelines for three related things: tying the neg(-) conductors at some point; isolating the 120VAC from the hull/water; and insuring there is an isolated safety ground with shore power.
Click to expand...
Exterior not aluminium. It is a converted minibus VW crafter....so thin sheet steel id imagine....typical van.
 
Solarfun4jim said:
Moving RV. He envisions a short earth rod pounded in with a hammer and soaked with water. I dont fancy the idea myself, but everyone says that i must get the system 'checked out by a qualified electrician', but having done so, i'm now getting told frequently that he is wrong in his assertions. :unsure::cry:
Click to expand...
I'm sorry to say that I'm rescinding the offer to camp in my driveway ;)
We can still hang out though.
 
Solarfun4jim said:
In a rubber tyre insulated motorhome, is there any downside to attaching an earth rod to the chassis when parked up, when using 240v ac inverter power only(no grid tie or grid earthing) ?
Is it safer with the earth rod connection or not?
Click to expand...
Without it.


Solarfun4jim said:
Thanks for all the replies folks. I have an electrician friend that insists i need an earth rod for the RCD to work.
Click to expand...

Are the RCDs not tripping when you press the test button?

Looks like this is the UK, there they have what is known as TT system, they do in fact sometimes use the earth as EGC, but because the earth resistance is too high the upstream breaker needs to have RCD protection, otherwise a ground fault would only make things more dangerous.

IIRC TT is no longer being used in the UK.

They likely are trying to apply the logic of TT systems here.
Solarfun4jim said:
@Boondock Saint

Thanks for your reply boondock saint...

I thought i had all the grounding worked out, but a qualified electrician friend has thrown a spanner in the works by insisting that i need an earth rod for RCD protection.

As regards boats, if they have a metal hull, would this not conduct through the water back to earth?

The reason i keep asking questions as im getting so much conflicting information and i'm paranoid about electricity. I need to be 100% confident my vehicle is safe, not 99.9%

See my rough earthing drawing of current setup...care to comment?View attachment 53057
Click to expand...

What is SCC?

Are you sure the inverter has a neutral to earth bond inside? If that's the case then the diagram is 100% safe. If the inverter does not have the bond RCDs will not work, but that does not mean that it is not safe 100%, other european countries allow you to have ungrounded systems, no idea if in the UK you can.

When you have an ungrounded system there is no potential between live and chasis, meaning that you cannot get a shock by touching just the live wire, you would need to touch both live and neutral and nothing can protect you against that, not even RCDs with a grounded system.
 
time2roll said:
Best to ask here: https://forums.mikeholt.com/forums/bonding-and-grounding.22/
Click to expand...
Holy cow
I’ve not run across that before but the paragraphs I just read are simply fantastic. It’s like the engineer’s knowledge viewed with the eyes of an electrician and spoken in plain English with not just the rule, the how, snd the why, but also the dangling “because” context that so often gets missed.
i can write like that about a few subjects but not general electricity (or at least not NEC stuff regarding 120VAC).
I am impressed. ‘Because you’re supposed to’ has never been an adequate explanation to me for anything.
 
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