Generators Earthing Shore power etc.

J

jimbouy

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Hi all,

This was asked on a thread in the lounge but never really answered so hopefully I can stimulate some interest here.


As I don't have power on my home pontoon and I seem to use far more power than I should (too many gadgets) , I have just purchased a Kipor 1300t from Ebay.

Firstly... lets not have a debate on £30 B&Q versus the rest etc etc as that's been done.

My intention is to plug the output in to my shore power connection which in turn connects to the battery charger. So on my visits through the winter I can top up the batteries and listen to the radio whilst I tinker.

OK.. to the point. The genny has an earthing point and the instructions are to connect it to an earth spike.

So what to do in a marine situation?

My shore power goes thru a galvonic isolator and is protected by an RCD type device. (I have a dolphin all in one to be accurate)

The shore power was installed as per the instructions from Merlin, so the mains earth is also bonded to -12v.

So do I earth in some way?
Will the RCD still protect me?

All replies welcomed..

Rude ones may be ignored tho!

I have read all the manuals concerned.

/forums/images/graemlins/wink.gif

Jim
 
Just attach the genny to an earth spike, it's to protect you from shocks from the genny, if the power side goes to earth (chassis). Your system should work fine.
By the way, I've never understood why you should connect the mains earth to 12volt. Mine isn't and I have no intention of doing so, I keep the voltages totally seperate, apart from through the charger.
 
Ok. I should have worded my initial post better.... I always know what I mean tho!

So this earth spike? where abouts on the pontoon do I hammer it in? /forums/images/graemlins/shocked.gif Or do I dangle a lump of metal in the water?


As for earth to -12v ...... as per my electrical install instructions. I'm not claiming to understand why either!

JIm
 
This one?

"Earthing" can be achieved by either connecting the earth terminal to your hull anode lead hence "earthing" via the anode to the sea or by hanging a lead over the side. You could connect a length of scrap copper pipe to the lead to give a larger surface area for the earth connection. Steel hull vessels "earth" through bare metal surfaces below the waterline such as propellors or anodes etc.

The assemblers of the above genny claim it has a cleaner output than other low cost gennys but even so the instructions do recommend using a surge protector if running a computer - this recommendation should be expanded to include any electronic equipment such as a smart charger but as you have read the manuals I assume you picked up on this point and have aquired a surge protector as well.



Looks not a bad little genny for £223.34 delivered or less on ebay I suppose.
--------------------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
 
You need to ask what the earth is there for ... now I don't claim to know huge amounts about electricity ... but my view is that the Earth is there to protect the user from stray current from faulty equipment/cabling by providing a better/faster/more attractive route to "earth". Double insulated equipment does not (usually) have an earth lead.

So ... I guess the question is - what is going to happen with your 240v equipment on the boat should the case become live .... - well, it will make its own Earth cable live (assuming it has one) and should trip any RCD protection you have .... so for the Generator, whether it is on the pontoon, bow or stern it should have some sort of earth - I would suggest it needs to be a large surface area bar, dropped into the sea should do .....

************************************************************************
Use this advice at your own risk - If you kill yourself having followed the above don't come crying to me.
************************************************************************
 
Hi Cliff,

Yes that's the one. It seems to be good value when purchased on Ebay, especially if you collect rather than pay for a courier.

OK. I was already considering that a surge protector would be a good idea, but your post has made me go back and re read the manual. I can't see where it mentions a surge protector.
Please clarify?

As for earthing... the copper tube was what I had in mind


Jim
 
Hi Fireball,


No argument as regards to 240v and the reason for earthing. The idea is indeed to provide a rapid route and thus allow a high ampage to flow so any fuse will pop. Or RCD device etc.

My knowledge goes a bit more vague when it comes to marine. I had it in mind that a cable with copper tube dangled over the side would be easiest and would then insure function of the fuses minitrips and RCD.

Jim
 
I reckon the output of most generators, especially the bettermade ones, have a very good voltage regulation where it is 240v ac or 12v dc. Your onboard charger should be able to handle small fluctuations of input ac voltage as well, I know the Sterling one takes anything from 100 - 300 v ac so they can be used in just about any country. All IMHO. We supply CCTV transmiiters and receivers all round teh worlkd and have to fit small 240v ac - 12v dc power supplies and they accept just about anything on the input, never had one back and they work in the jungles of Vietnam to the deserts of teh Middle East.
 
Yup - I guess copper tube would be absolutly fine ...

Now - any idea if, when at anchor, you could deliberatly "charge" the tube and stun some fish for supper? Or do I need to go back to the Hand Grenade method?
 
Please read this

I have done exactly what you're proposing, except that I have a Honda EU10i. The problem you will have is with your RCD, the moment you plug in your generator, the RCD will trip. The RCD is configured to operate from the mains supply with an earthed neutral, and not from a generator with a floating earth. To allow the RCD to work, it is necessary to modify the generator so that it is configured in the same way as the mains supply. The easiest way to do this is in the plug on a short lead from the generator to the shore supply inlet (which is what I did) . Simply put a short piece of wire linking the earth and neutral connectors. This ensures that the generator is unmodified when it is disconnected from the boat, and therefore remains safe. You should clearly mark this connecting cable with "GENERATOR ONLY. NEUTRAL EARTH LINK - DO NOT CONNECT TO MAINS".

Note that you are ONLY protected on circuits AFTER the RCD (push the test button - it will work as normal).

There are various articles on the web which tell you about this. For example see: http://www.hondagenerator.co.uk/pages/FAQ.htm This talks about connecting a generator to your house supply in an emergency, but the principles are the same.

Cheers,

Jerry
 
Re: Please read this

[ QUOTE ]
But I can't get to grips with what a floating earth is!

[/ QUOTE ]
Thats when the copper tube has thin walls and you seal both ends resulting in it floating !!
 
Re: Please read this

Please be very careful. Your generator is not a honda and may be configured differently.
I have just looked up the spec for your machine and see that it is a camping and liesure machine with one 230volt outlet. It may, or, may not be already configured with an earthed neutral. That is the same as a domestic supply.
I cannot tell from the spec and as a qualified electrician I would not be able to give advice without inspecting the machine.
I would therefore suggest that your best bet is to ignore all the well meant good advice on the forum, take the machine to a local electrical engineer with generator knowledge before attempting any modifications or using it and get his professional opinion.
Hope I don't upset anyone with the above but I think it is the safest option.
 
[ QUOTE ]
but your post has made me go back and re read the manual. I can't see where it mentions a surge protector.
Please clarify?

As for earthing... the copper tube was what I had in mind
Jim

[/ QUOTE ]
Sorry - it was on the website I read about using the surge protector - I assumed they would put the same info in the manual.
--------------------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
 
Re: Please read this

A Residual Current Device on the generator will typically monitor the currents flowing in the live and neutral output from the generator. If these two are different by the rating of the RCD - which may on a small machine be from 100 to 10 milliamps (lower figure gives better protection) the output of the generator will be disconnected. The generator itself may develop an internal fault whereby a voltage is developed on its casing. This voltage could potentially pass through anything/body coming into contact with the casing and to prevent a problem the manufacturer provides a means of connecting the casing to earth. The earth wire in the output may also be connected to the casing. This earth link may be further extended by equipment which is connected to the output cable depending upon the nature of that equipment - clearly double insulated non-earthed will not improve the earth connection. Thereby each additional earth improves the quality of the earth connection.

If many generators are run without a properly earthed casing it has the potential to become live under fault conditions.

An earth spike or alternative earth connection in wet conditions seems prudent. The object of the exercise has to be to ensure that the alternative route to earth is better than the route through someone touching the machine whilst being wet and standing in a puddle. /forums/images/graemlins/shocked.gif
 
Nice genny the kipor. Also bought one off ebay for the boat yard sanding days and it runs all day quite happy. Only advice I would give is if you have the white sockets on the panel connect a small extension lead ( I have mine connected to the handle) so that you won't have to keep removing plugs from the sockets. If you don't the panel sockets will fall apart very quickly if you keep putting plugs in them
 
A RCD works on the basis of the current that goes up the + must come back down the -.
Because it is AC the magnetic forces generated by the current are equal. If more current goes up th + than comes down the - it must be going to earth ( via something or someone). This causes the RCD to see an unbalanced load and trip.
 
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