Generator Earthing

Kantara

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After I lost all power in the batteries last year after an engine failure while crossing the North Channel led to me taking 3 days to beat up the Sound of Jura to Ardfern, I bought a cheapo generator from Aldi. It seems to run very quietly and powers my drill and battery charger very well, but one of the instructions is to connect the chassis to an earth rod screwed into the ground. This could be a bit of a problem on my swinging mooring. Can anyone make any suggestions as to whether it is necessary and, if so, how I can do it when afloat.
 

nedmin

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Yes you should earth it but I dont know anyone that does, most power tools are double insulated so dont need an earth. If you open the plug,if there,s only 2 wires its double insulated. If its a 2stroke stop it each time by switching off the fuel and it will start easier next time.
 

VicS

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The most you can do is earth it to the boats "earth". That is the shorepower earth, if you have a shorepower installation, and the negative side of the 12 (or 24) volt system, assuming you have a negative earth system, and all the things like anodes stern gear etc.

You seem to be lucky compared to other forumites in getting one that works!
 

alanporter

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I connect the earth wire to a piece of copper pipe which (rightly or wrongly) I dangle over the side of the boat. If there is an electrical short I suppose the fishes will feel a tingle, but at least it protects me and my crew.
 

VicS

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[ QUOTE ]
I connect the earth wire to a piece of copper pipe which (rightly or wrongly) I dangle over the side of the boat. If there is an electrical short I suppose the fishes will feel a tingle, but at least it protects me and my crew

[/ QUOTE ] I can't see what good that is doing at all.
 

Clyde_Wanderer

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Dont think about drilling a hole in hull and sinking an earth rod into the sea bed, it might sink the boat, or you might sail away and forget to pull it causing even more damage /forums/images/graemlins/laugh.gif
 

Clyde_Wanderer

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All joking aside, I think what the instructions mean is to connect an earth from what ever appliance you are using to the chassis of the gennie, but as someone else has said if its double insulated you wont need one as it wont have an earth.
There should be a, Square inside a Square, symbol on the tool if it is double insulated.
 

fluffc

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There was a huge thread on this subject about a month ago. There was no definte answer to the problem - as you say, there is no obvious 'earth' equivalent on a boat.

Any boat-generator experts out there able to shed some light?
 
A

Anonymous

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The purpose of earthing is twofold. First, metal parts can become live and if touched can cause a shock. If you earth the metal parts, instead of becoming live they short the supply to earth which either blows a fuse or trips an earth leakage breaker. The second purpose of earthing is to reduce the chance of fires; if there is a good earth then when things get hot and insulation melts, at some point there is a good connection to earth which blows the fuse.

A mains generator might need to be earthed. If the chassis becomes live due to some fault it could become lethal. The problem would arise if one part of the chassis was held to genuine (sea water) earth through the deck and another piece of exposed metal on the generator became live. Could kill instantly whether or not an earth leakage breaker was used, fuse fitted or doubly insulated equipment used.

Do as another poster suggests and earth to sea water. A copper pipe is fine. Then put an earth leakage breaker on the output.
 
G

Guest

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[ QUOTE ]
All joking aside, I think what the instructions mean is to connect an earth from what ever appliance you are using to the chassis of the gennie, but as someone else has said if its double insulated you wont need one as it wont have an earth.
There should be a, Square inside a Square, symbol on the tool if it is double insulated.

[/ QUOTE ]

Both my gennys ... the Wolf 800 and B&S 3400 have humb screw terminals on the chassis ... in the manuals it clearly states to connect an earth lead from this terminal to a stake driven into the ground.

The idea of a plate dangled overboard has crossed my mind - but where is the circuit if a short does occur ? The average GRP / timber boat is a pretty good insulator...... so how does it protect anyone ?

The old matter of grounding -ves of 240 / 12 etc. Considering that literally no 2 books on the subject agree totally ... my boat has never suffered galvanic corrosion or stray current eroding prop etc. So I refuse to do this and introduce possible start of this phenomena ... OK their are now going to be numerous posts saying I'm a berk for this and shouldn't advise others - I am NOT advising others to follow my example in this ... just commenting. That then brings me to the genny ... grounding via same point - ???????
 
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