# 150watt Inverter



## fdhadi (May 9, 2005)

Bought a 150watt Inverter today (Nikkai).

At one end there is an Earth wing nut terminal with no wire.
Where could i earth this to in the back of the M/H  .
There is a 240 socket next to the cigar type socket that will power
the inverter, could i link the earth to this earth (240) :? .

Regards
Frank


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## antnjac (May 12, 2005)

Have read somewhere very dangeous to connect input of inverter to any part of 240 volt system.If fault in 240 volt system very high volts could come out of front of inverter? I have connected my earth from back of inverter to drivers seat base :lol: . the input wires should be as short as possible.

Tony


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## 88808 (May 9, 2005)

The earth for a 240V inverter should actually be EARTHED! ie stake in the ground. The same goes for gen sets. The output is mains 240V ac which is no different to a domestic wall socket. The whole point of the earth wire is to give the current an easy route to the ground, rather than travel through a person holding an appliance. 

If the vehicle is already wired up for 240V the system will be designed to connect to a hook up, therefor the system will not be earthed properly unless the hook up is connected, even then there is no guarantee that the site end of the system is actually earthed properly. 

The inverter will happily operate without being earthed, you just risk being electrocuted as you will be the quickest route for the current to follow to the ground 8O


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## 88724 (May 9, 2005)

Hi Jonathon

What you stated is far too simplistic, ignoring Gennies, most invertors have no connection at all between the Earth pin on the invertor socket and anything.
The Nikkia unit connects Earth pin to case chassis and to the Negative terminal of the Battery, this is in direct contravention of the 16th edition wiring regs which state there must be no direct connection between Low Voltage (240v electric) electrics and Ultra low voltage (battery type votages)

However what this does do is makes an RCD possible to work! 

without the contravention an RCD would not work, BUT if the Neutral earth is not bonded (Like on virtually every other invertor!) the only way to get a shock is by holding live and neutral togethor, simply making contact with live or neutral alone would not give you a shock (as there is no return path!)

Many many invertors have no earth pin connection, with this type there would be no possibility of getting shock because earth (ie ground the floor etc) is never going to make a circuit.


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## 88808 (May 9, 2005)

Trust me to be simplistic :lol: :lol:


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## 88724 (May 9, 2005)

Hi Jonathon

Not Simple as in concise clear and brief, but as in, could prove fatally incorrect.


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## 88808 (May 9, 2005)

shocking!


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## fdhadi (May 9, 2005)

Thanks Tony / George / Jonathon,

will connect it to the drivers seat frame ( 3ft away).

Regards
Frank


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## johnsandywhite (May 9, 2005)

8O So *George* qoute:-

However what this does do is makes an RCD possible to work!

without the contravention an RCD would not work, BUT if the Neutral earth is not bonded (Like on virtually every other invertor!) the only way to get a shock is by holding live and neutral togethor, simply making contact with live or neutral alone would not give you a shock (as there is no return path!) 
end qoute.

So what you are saying is if I was to take hold of the LIVE wire I would not get a SHOCK? :roll: 8O


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## 88724 (May 9, 2005)

Hi John

Yes I'd Bet your life on it !


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## johnsandywhite (May 9, 2005)

No way Jose *George*. Anyway on the subject of batteries? Here are a few pointers:-

The battery charge process:- http://www.amplepower.com/primer/full/index.html

How to Kill a Battery:- http://www.amplepower.com/primer/kill/index.html


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## 89425 (May 23, 2005)

What George says is correct.

Sadly many people think their RCB is okay when the press it’s test button when used with an inverter. To reiterate, this is NOT the case when RCB’s are used with inverters as they are an isolated supply and nothing to do with the normal national grid system you use at home.

There is no easy way to test your RCD with an inverter without specialist test equipment


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## 88724 (May 9, 2005)

Hi John

As long as you have the right kind of Invertor there is nowhere for the current to go a circuit needs to be completed between Live and neutral or between Live and earth.

If the invertor as no contact with Earth were would the current flow to? Ergo you would be perfectly safe. Its knowing which type is which.....


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## johnsandywhite (May 9, 2005)

8O So. When I disconnected my 800 Watt Invertor and just happened to touch the live end why did it flash and spark? (I know it still holds a charge within it even though it is disconnected). There was no other connection. Just the live shorting through the screwdriver to the case. :roll: 8O


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## 88808 (May 9, 2005)

GeorgeTelford said:


> Hi John
> 
> Yes I'd Bet your life on it !


Why not bet your own life on it George :wink:

It is strange that the electricity knows that it was changed from DC to AC inside an inverter and that it doesnt need to follow the easiest route to earth like it should?

Looks like you found another loop hole in the law George, well the laws of physics 8) Well done.


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## johnsandywhite (May 9, 2005)

Red_Dragon_Bus said:


> GeorgeTelford said:
> 
> 
> > Hi John
> ...


Now by stating that, you are going to open a can of worms. Because it is actually STILL DC. :? 8O


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## 88724 (May 9, 2005)

Hi Jonathon.

It is clear from your last post that you have no idea what you are talking about.

Have a look here Earthing systems

You will notice that all show the centre tap of the generating companies end grounded to Mother earth. thats on every different earthing system have a look at them all.

Therefore when you stand on ground and grab a single live wire you will be electrocuted.

However:

With most invertors the earth pin is connected to nothing, therefore the only way to get electrocuted is to have hold of live and neutral.

Because there is no connection between live and the chassis of the vehicle and or mother earth there is no return path ergo no circuit and no possible shock.

With the Nikkai Invertor (which breaks IEE 16th edition regs because low and extra low voltage are connected) a shock is possible because the Chassis/earth/Negative terminal are all connected.

The segregation regs are here 16th edition re low and extra low voltage 

So Jonathon if it (the invertor) follows regs and is not bonded it would be impossible to complete a circuit because there would be no earth for it to run too.


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## fdhadi (May 9, 2005)

So, is it ok to Earth this to the seat frame or not??????????

Regards
Frank


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## 88724 (May 9, 2005)

Frank

Internally the Nikkia invertor connects Earth on 3 pin socket to Neutral, also it connects to the case of the invertor, and to the Negative battery terminal.

Therefore as soon as you connect it to the battery the case will be connected to the seat and every other pce of grounded metal within the vehicle anyway regardless of whethor you add a pce of wire to the wing nut and attach it.

I have stated the Regs position on this, it is against the 16th Edition wiring regs, it is also against supply regs to have earth and neutral bonded within a property (in this case a leisure vehicle), it also contravenes the special Installations section for caravans motorhomes and caravan parks, Click on this text to see the relevant section

I have explained that because of this a RCD will now work, on a normal invertor the RCD will not work.

I have given the relevant information, it would be extremely foolish to tell you exactly what to do in this situation as any suggestion is automatically against the 16th Edition, regardless of how safe it is.


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## 88726 (May 9, 2005)

hi guys

yes frank its ok mate .


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## 88808 (May 9, 2005)

That's all very exiting, so there is no potential difference between the live wires outputing AC from the inverter and the ground. So there is no way that the current could travel through you to the ground even if you were holding a bare cable and stood bare foot on the ground. 

The only reason I mention the laws of physics, when I worked at sea, we were trained to perform helicopter operations, we had to ensure the aircraft dipped the hoist wire in the sea to discharge the static electricity generated by the helicopter before starting operations, then we had to use rubber gloves/boots when handling the wire to prevent us earthing the aircraft with our bodies.


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## spykal (May 9, 2005)

Oh Jonathan

look what you have done now....you have gone and brought up static electricity, a whole new "ballgame" .....gawd help us......we will be into electrons, neutrons and positivly charged protons.............I think I am off for a lie down in a darkened room :williamshatter: 


mike


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## 88726 (May 9, 2005)

thats the trouble with those [email protected]@dy electrons ,theyre allways trying to increase there potential 
:lol: :lol: :lol: :lol: :lol: :lol: 

i think :?: :wink: 

cheers
kenny+stella


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## 88808 (May 9, 2005)

It's a very electrifying subject :idea: 

:lol: :lol:


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## 88724 (May 9, 2005)

Hi Jonathon

Quote

So there is no way that the current could travel through you to the ground even if you were holding a bare cable and stood bare foot on the ground. 

End quote

With a Sterling Invertor (and many others) there is no earth as such and so as far as the invertor is concerned no different potential, there is no return path.

The only way to get a shock is by holding live and neutral togethor.

Lightning and static from aircraft are a different ball of beeswax and are completeing a circuit anyway just one thats not easily visible


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## 88808 (May 9, 2005)

As I said, it is exciting


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## 89351 (May 20, 2005)

*RCCB for inverter output*

Just to thicken the plot a tad; the following 2 pole RCCB does work with both quasi sine & real sinewave inverters, irrespective of earthed neutral or not:

Manufacturer: Merlin Gerin
Type: RMG160102
Rating:16 amps
Fault current: 10mA


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## 88724 (May 9, 2005)

Hi Peter

I have Just rang and confirmed that the RMG 160102 WILL NOT work with any invertor, unless Neutral and earth are bonded.

Schneider Electric Ltd
University of Warwick
Science Park - Sir William Lyons Road
Coventry CV4 7EZ
United Kingdom
Tel: 44 0 870 608 8 608
Fax: 44 0 870 608 8 606

UK Distribution and Tech

Quote

They have a residual current operated electro-mechanical release which operates without any auxiliary source of supply to open a circuit automatically in the case of an *earth leakage* fault between phase and *earth* greater than or equal to a threshold of 10, 30, 100, or 300mA.

Endquote

An RCD works by measuring the difference between Live and Neutral, in reality the only other potential is earth and this is only because the center tapping of the Supply companies generator is taken to earth.

An invertor that as not been bonded between earth and neutral will not trip an RCD because there is no other Potential to escape to.


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## fdhadi (May 9, 2005)

Thanks,

:idea: *Its going to the seat base.*
Thats all i wanted to no!!!!!!!!!!!!!!!!!!!!!!!

Some of these replies are shocking.
Their will be some sparks flying here soon :twisted: .

Regards
Frank


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## johnsandywhite (May 9, 2005)

Another Happy Customer then? 8O


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## 89351 (May 20, 2005)

*RCCB for inverter output*

George, it depends what question you ask - the RCCB does open in the event of a difference between Live & Neutral current - if there is a difference, then it is flowing somewhere else & may therefore be hazardous.
As you say, if the inverter output is truly floating, then there is no hazard in touching either the L or N conductor. In the event of an external L or N to vehicle "chassis" fault, causing the opposing conductor to become "live", then the trip will operate if the "live" conductor is touched, as there is then a current imbalance in the RCCB. It is true that the RCCB does not detect an external L or N to vehicle "chassis" fault, but this in itself is not directly hazardous. Just to confuse matters, as you may be aware, US regulations require that the inverter Neutral is vehicle chassis bonded. The argument about inverter safety on vehicles has been circulating for some years & the difficulties come about in trying to apply the wiring regulations, which are concerned with an incoming mains supply which is already earth referenced. The inverter output is not earth (true earth) referenced, & does not present the same hazard as the mains anyway.
In conclusion, the Merlin Gerin RCCB does "work" with an inverter - inverter safety on a vehicle is a muddled issue. Rather than confuse our avid readers by cluttering up the forum with techno-speak, please contact me by e-mail, if you wish, & I'll phone you with the full story. [email protected]


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## 88724 (May 9, 2005)

Hi Peter

I always prefer out in the open. But I have emailed you too ! The thing that surprises me is how many different opinions there are even amongst qualified electricians, some disagree with 16th Edition and think bonding is the way to go and to a degree it maes sense.

Yes it is a very muddled issue, one which I have discussed with several qualified electricians up and down the country.

The reality is that if there is no "earth" (or different potential) and with an unbonded invertor there is no other potential, then RCD will not work, but that is no less safe because it would take a live and neutral short to harm you (even with RCD in place it will not protect against a Live neutral short)

The flying Scot said yes mate its ok and in reality its just as safe as the other method, BUT it does contrevene the regs, my posts were designed to tell the questioner what happens under a range of circumstances and the regs that apply, given that information its down to Frank what he does.


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