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Gary Dean

I wish to dispute the way you have put the question about earthing Generators "Should I earth it?" (W.W. February 2017 page90) I did not ask any such question. I would please like it to be corrected. What I did say and ask is as below (as in this forum). Please can you Mr Smedley not change the way questions people put to Waterways World. My question was as below [June2015]:-
Generator Grounding (Earthing)
Dear Sir,
I have just brought an IG770 Kipor generator for use on the bank. My boat being Viking 28, is of GRP construction. I had to ask the company (Kipor)direct about what is required to earth it (Grounding). Before looking on the internet it is not so simple as to just stick a bit of metal into the ground. For starters using a thicker grounding rod does not reduce the resistance from rod to earth[when earthing a power station but may apply to a degree] . The length of the grounding rod is important and also what substrate you are sticking it into (gravely soil, sand, wet soil or dry, clay etc). It is impracticable to use a four foot rod as it may well bend or be impossible to pull out of the ground. If using more than one, they should be spaced not nearer than the length of each one's depth in the ground. An Ohms test should be done between the earth cable hence the thick cable required from the generator to the rod or rods. The mind boggles if you start to look deeper at the subject.
We are interested in our own generator set, so require the earth rod or rods for what our generators max power can produce, plus (at a guess) 30-40% to be on the safe side. My boat is of GRP construction.
Kipor told me to use as followed. [I can email the information from Kipor along with drawing if required].
Materials needed:
1. a copper wire(cross sectional area 2.5mm2)
2. a threaded copper rod(diameter 10mm, length 600mm)
3. an ohm meter
Operation steps:
1. Find the ground terminal on the panel
2. Twin the terminal with the copper wire
3. Twin the copper rod with the copper wire along the threads
4. Insert the cooper rod into the earth, the cooper shall not be above the earth for more than 150mm, a warning sign beside the cooper will be better
5. Measure the resistance between the terminal on the panel and the cooper rod, the resistance shall be lower than 4 Ohm, or, please use shorter copper wire
Not quite what you may have expected(??) 2.5mm2 but may be ok for max 770 Watts output!
Yours Sincerely
Gary Dean.
WW subscriber.
PS I have seen generators this year at WW boat show along the canal at Crick, without any grounding, quite big lumps too. They must be mad or stupid idiots.
Asked by: Gary | Tuesday 9 June, 2.29pm | 3 answers

Asked by: Gary  | 3.42pm, Friday 13 January

WW says:

I have to hold up my hand here & take the blame. Apologies. The questions and answers are used in the magazine, but there is only so much space, typically 200-300 words in total for both Q&A.
In this case the question itself was longer than the total space available, so I took just a subset of the question & answer and tried to make a single item of it, to fit the space available.
I had planned to use a nom-de-plume, to 'unlink' it from the original question, but the questioner's original name slipped through, my apologies again.

Andrew Denny  | 4.43PM, Tuesday 31 January

Readers say:

Re:Gary Dean - Generators. Sorry Mr Smedley this should be a complaint to the Editor of the page.

Gary  | 1.48PM, Tuesday 17 January

The effectiveness of the earthing rod will surely depend on how damp and hence how conductive the soil is that it is driven into. Taking this logic further would suggest that the best earth would surely be to dangle the copper rod into the canal/river?
The measurement of the resistance of the copper wire between earth rod and earth on the terminal panel is a little bit academic since if it is only 5 - 10M long it should be fractions of an ohm I.e. Nowhere near 4ohms. This test is really a confidence checker to prove that there is a solid earth connection wire present to the earth rod. It does nothing to prove that the earth rod in the ground is actually effective.

R Tanzer  | 4.55PM, Saturday 11 March

Yes, it does matter what you are sticking the ground rod into as I had said in my question above.
The answer I was given from KiporĀ®, was what would be required for my sized generator, the Kipor IG770. The advice for earth bonding is not specific to boaters. My earth lead is only 2 foot long at 4 mm2. (Minimum 2.5mm2 max length un-known) I see no practical point having a longer earth lead. I have not checked the resistance. Yes it makes a difference what you put the earth rod into (rod is usually copper bonded on steel). There are regulations that Kipor have to follow when giving me information. This PDF from FLUKEĀ® gives some idea of resistance in soil. see page 5, https://support.fluke.com/find-sales/Download/Asset/2633834_6115_ENG_A_W.PDF
AS regards of dipping the earth lead or rod into the water may not be a good idea if close to or down the side of your (or another) boat if made of steel. You could be talking 3 or 4KVA generator attached to it. I'd be interested to here from an expert on this point.
Also I would not want my earth leads trailing over the towpath.
I would like to see guidance from the Boat Safety Scheme about what requirements for grounding portable generators. Could a graph be available from 0.5kVA to say 4KVA.
Can any experts explain resistance as regards length of Grounding leads and Grounding for portable generators. Is the 4 ohms correct? or is it a type error, so should be o.4ohms?
A tip on earth rod removal:- Drill through the centre of 8" length of dowel or broom handle, and slip that on the rod to pull the rod out after use. You may have to pin through the cable clamp & rod to stop it pulling off the rod.

Gary  | 11.44PM, Monday 13 March

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