Inverter earth or not?

bjh

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My van conversion is finally getting a bit of a move on, especially as I need it this Thursday for a couple of days. Do I connect the inverter to the 3 core hook up cable or not? Seem to be conflicting views on this. My existing one is a pure sine wave unit that says on it floating earth, so presumably this should not be earthed, but I am not sure. Any help much appreciated.
 
Beleave it or not they say no shock can be had from an inverter, but if there is a earth pin on it i would fix it to the van body chassis the have a earth spike with you to shove into the ground with a lead and croc clip so to attach to the van somewhere, wet ground is best, if dry pore some water round it.
 
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I earthed mine, why? Because the "destruction" manual said to :unsure:
I do wonder though if being "above" ground and supported by four nice shiny round rubber insulators if it really makes a difference :confused:

Regards,
Del
 
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alwaysared said:
I earthed mine, why? Because the "destruction" manual said to :unsure:
I do wonder though if being "above" ground and supported by four nice shiny round rubber insulators if it really makes a difference :confused:

Regards,
Del
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Like you Del I earthed mine to the body work not that it would make any difference.
 
I think it’s been explained on here before but I forget the reasoning. A search will bring results I guess though lol
 
It is in effect earthed via the negative terminal on the battery which is earthed to the chassis or should be,
 
As per most manufacturers manuals an inverter chassis should be correctly earth bonded to the vehicle chassis assuming it is provided with an earth point.

Google and read bs7671 section 721 for relevant info for 230v AC installations in motor caravans.

If you can’t understand it then don’t take silly risks, contact a certified domestic electrician for assistance
 
CriftinsCampers said:
As per most manufacturers manuals an inverter chassis should be correctly earth bonded to the vehicle chassis assuming it is provided with an earth point.

Google and read bs7671 section 721 for relevant info for 230v AC installations in motor caravans.

If you can’t understand it then don’t take silly risks, contact a certified domestic electrician for assistance
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So, please explain what that will do if you don’t connect the vehicle to a ground spike please?
 
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I'm not sparky, ask David or Merlin :D :D

But the only reason I can think of to earth it is H&S from the manufacturer and it might help if it's badly made and can make the casing live
 
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Pudsey Bear said:
I'm not sparky, ask David or Merlin :D :D

But the only reason I can think of to earth it is H&S from the manufacturer and it might help if it's badly made and can make the casing live
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I have a feeling this is more relevant to people who use campsites and hook up Kev, probably more relevant to inverter chargers as well I don’t know.
 
The manufacturers manual made absolutely no comment about earthing! Still not clear, so have taken the earth leads in the 3 core cables back to the mains/inverter selector switch, but not connected to the earth on the mains cable. This way when all becomes clear I can connect if necessary. I have mounted the inverter on a steel back plate which is itself screwed to the vehicle body, so the inverter itself is actually earthed unless the workings of it do not make contact with the casing. I can't see many people bothering putting out an earth spike, I would probably forget it and drive off towing the world around a little faster:)
 
Don’t go off what I say regarding this as I am certainly no expert. I am just saying what I do or don’t do. I do remember researching it a few years back but don’t now remember all the ins and outs of it.anything earthed on the 240v side has to have a route to earth for it to do anything I ‘think’. That would usually be a hook up lead on a site or an earth spike, again ‘I think’.

I don’t use much 230V gear in the van and if I ever go on site and hooked up I wouldn’t use my inverter. All my 230V stuff is double insulated so not using earth in anyway I believe.

Hopefully a sparky will correct this if wrong. Works fine for me but everything always does until it doesn’t lol
 
nabsim said:
So, please explain what that will do if you don’t connect the vehicle to a ground spike please?
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Instead of the current flowing to earth if say a fault with a metal kettle then you will maybe require the attention of a undertaker.
But if some you use is double insulated like a 500w plug in plastic heater then nothing will happen.
 
trevskoda said:
Instead of the current flowing to earth if say a fault with a metal kettle then you will maybe require the attention of a undertaker.
But if some you use is double insulated like a 500w plug in plastic heater then nothing will happen.
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Kettle in my van is 2.2Kw Trev but it’s only ever used if I am on a site with hookup and I actually remember I have it, so hardly ever used lol it’s a plastic kettle anyway and everything is double insulated

My usual kettle isn’t very gas efficient either, it’s a big old Le Crusset or whatever they are called lol
 
Quandary - my Renogy inverter has a mains plug-in as it has a UPS function. So - does this mean it is earthed through the hook-up earth and therefore ‘safe’ and does not need an earth connection or as I have and use the earth point on it to chassis earth?
Might just contact Renogy for clarification….
 
You need to realise there's a difference between actually earthing something ie making a connection to plant earth and taking one of a pair of floating power terminals ( like those from an inverter) and connecting it to the earth pin of the mains outputs that it serves.
So dealing with the latter first:
Normal mains wiring in a household comes from the output of a local transformer and as such would float and would have no live or neutral and you would be safe to touch either wire ( but not both together) but the leccy board connect one of the power supply cables to planet earth, this cable now becomes a neutral and the other becomes live. If you now touch the live while you're standing on planet earth current will flow through the live cable, through you, through planet earth and back to the neutral completing the circuit and giving you a belt. This wouldn't have happened if the leccy board hadn't have earthed one of the output cables.
The output from the inverter is naturally floating, it has no live (and therefore no neutral) you can touch either cable and you won't get a shock, in order to get a shock you need to touch both wires simultaneously. This (typically) makes a floating supply very safe, for example you MUST have a floating supply where you have a power outlet in a bathroom at home, this is accomplished via a 240V isolation transformer that sits behind a razor socket.
So, why did they ever earth that pesky cable and create a LIVE? The problem with floating or isolated supplies is when you have more than one socket outlet connected to the same floating supply, ie connecting your van inverter to multiple sockets in your van, I'll explain..
Imagine a floating supply, remember no live and no neutral just 2 cables supplying 240v across them. Let's call these 2 cables Hot 1 and hot 2 and remember you can't get electrocuted unless you touch both simultaneously.
So you have a toaster with a metal case, it develops an internal fault and hot 1 shorts to the metal body, what happens? NOTHING! Unlike the system where they created a live and a neutral by earthing and output a fuse doesn't blow because theres nowhere for the fault voltage (in the casing) to go to. The user is oblivious, they keep touching the case but nothing happens because they're only touching Hot 1 and not Hot 2 as well.
Now consider the same kitchen and now the metal kettle develops a similar fault but this time it's hot 2 that gets connected to the metal body by a fault. Again nothing happens and no one ever notices UNTIL someone touches the toaster and the kettle at the same time, that person is now touching hot1 and hot 2 simultaneously with probably 240v across left hand and right hand with current flowing straight across the heart, hopefully muscle contractions will break the connection but if not you're dead.
The above can obviously only be an issue if you have 2 or more items plugged into the same inverter at the same time, using a single item doesn't present a risk.
So if you're wiring your inverter into your MH 240v system and you intend plug in more than 1 appliance with metal parts then you could protect yourself from the above and create a LIVE and neutral setup by connecting the left hand pin of the output socket to the earth system of the 240v wiring. I'll be honest and say I haven't bothered because every time we go on EHU the appliances are effectively tested against such faults and if had a live to earth or neutral to earth fault they'd blow a fuse or take out the RCD, in other words the appliances are regularly tested for faults.
Earthing the inverter, ie connecting the case of the inverter to planet earth??? What could that achieve???? Pointless I'd say.
Connecting the earth pin of the inverter to planet earth?? Why? Again pointless, it's probably not connected to anything internally anyway.
I guess there could be a scenario where the inverter develops a fault and hot 1or2 gets connected to the case of the inverter but connecting it to planet earth wouldn't achieve anything but connecting the inverter case to the earth wiring system within the van possibly wouldn't be a bad idea, I'd have to think about it🤔
 
Got all that 100%, and have read it on the net about inverters, hence i did not bother with a earth, and mine dont have one anyway.
Poor pudsey is now rolling round the floor with his head smoking. 😂 talk about overloading.
 
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