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Earthing a generator


pedroinlondon

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Hi all

 

I've bought a 2.5K W metal frame petrol generator (Briggs & Stratton Sprint 3200A) and was strongly advised to earthing it before using it again.

There are no instructions on the manual regarding this (or much of anyting else) and so I took to google for answers. I understand after a short general search that one way of doing this would be connecting a copper cable to the earthing nut of the generator and the other end of the cable to a copper rod (Screwfix product 87633?hammered a foot or so into the ground, preferably wet ground.

I understand there are several variables that may affect the reliability of the "system" (the quality of the connection of the cable to the rod;the state and type of the ground; the lenght of the cable; etc; etc) but does anyone have a tried and preferably tested way of doing this?

The genie is over 60kgs so I'd like to leave it on the roof of the boat, so the cable lenght will be around 3 meters. I have some 7mm multi strand copper cable left over, can I use it?

 

Ideas and suggestions welcome

 

Thanks

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5 hours ago, OldGoat said:

60 kilos on the roof and you'll tip over as well as deafening the neighbours - nothing around to deaden the sound...

I weigh about 85kg and the boat doesn’t tip over when I stand on the roof, however generators on the roof can be close to vents & windows which might under certain weather conditions put CO into the boat.

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6 hours ago, OldGoat said:

60 kilos on the roof and you'll tip over as well as deafening the neighbours - nothing around to deaden the sound...

I used to put 6 x 20 kilo bags of coal on the roof to keep the boat level. It probably changed the list to port from about 5 degrees, to zero. Not sure at what angle stability would disappear, but I think it would take more than double the 120 kilos, and maybe a lot more, to reach it :) 

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13 hours ago, WotEver said:

Check with a multimeter (set to continuity) if the earth pin on the generator outlet is connected to the generator frame/engine. If it is, then I see no need to run an earth spike. 

Hi Wot

It's not. There's a nut+bolt connection for a cable on it.
 

original.jpg

original (1).jpg

Edited by pedroinlondon
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I'd be more than a little concerned that the manufacturer doesn't appear to quote the 'noise levels'.

 

This looks like a typical Building site "frame generator", and, if it is then the noise reverberating around inside the boat is likely to make it impossible to be inside when the generator is running.

You are not going to be popular with any neighbours either.

 

https://www.briggsandstratton.com/eu/en_gb/product-catalog/generators/portable-petrol-generators/sprint-3200a-portable-petrol-generator.html

 

The picture shows an earth strap running from the generator to the frame.

 

 

Edited by Alan de Enfield
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44 minutes ago, Alan de Enfield said:

 

I'd be more than a little concerned that the manufacturer doesn't appear to quote the 'noise levels'.

 

JustGenerators lists it as 74dB! (But no distance is stated, nor the weighting). 

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Let’s look at noise levels first.

Many areas have noise regulations that may impact generator usage, particularly at night. This is especially the case for residential areas – so if you’re planning on using the generator around the home or work shed, you must consider the noise level. For obvious reasons, loud generators are also not recommended for camping, caravanning and outdoor events unless you want to make enemies!

The good news is most generators are labeled with a decibel rating. This is measured at an industry standard of seven metres away from the source (in this case, the generator).

Here’s how it works: for every increase in 10 decibels, the generator noise level is roughly doubled. So a generator that runs at 70 decibels is ten times as loud as a generator that runs at 60 decibels.

 

Image result for decibel comparison chart

 

 

generator noise level

https://www.mygenerator.com.au/blog/4-asked-question-heavy-noisy-generator/

 

Edited by Alan de Enfield
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1 hour ago, Alan de Enfield said:

Here’s how it works: for every increase in 10 decibels, the generator noise level is roughly doubled. So a generator that runs at 70 decibels is ten times as loud as a generator that runs at 60 decibels.

No, it is twice as loud. Because it is 10dB louder, which is a doubling of loudness (more or less). 


3dB is a doubling of power. 
6dB is a doubling of SPL. 
10dB is a subjective doubling of perceived loudness. 

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4 minutes ago, WotEver said:

No, it is twice as loud. Because it is 10dB louder, which is a doubling of loudness (more or less). 


3dB is a doubling of power. 
6dB is a doubling of SPL. 
10dB is a subjective doubling of perceived loudness. 

 

Yes - That's what the table shows.

 

Image result for decibel comparison chart

 

So, the difference in 'loudness' between a Honda EU200I (52dB)  and the Briggs and Stratton frame genny (74bD) is "it is 4x louder" to the ear.

Edited by Alan de Enfield
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Just now, Alan de Enfield said:

The article I quoted did say that, but the table below showed the loudness' was 2x but the 'sound intensity' was 10x

I’ve emailed them before about their text being incorrect. They didn’t reply and they didn’t correct it. 

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When specifying standby generators in cities such as London, I used to require 70dBA 1 metre from any inlet or outlet, including exhaust and 50dBA at 1 metre at the site perimeter.

 

Anything noisier than th2st will upset close neighbours if the generators run for any length of time.

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41 minutes ago, cuthound said:

When specifying standby generators in cities such as London, I used to require 70dBA 1 metre from any inlet or outlet, including exhaust and 50dBA at 1 metre at the site perimeter.

 

And I assume you can't buy anything that quiet which is portable and at a price the average boater is prepared to pay.

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21 minutes ago, David Mack said:

 

And I assume you can't buy anything that quiet which is portable and at a price the average boater is prepared to pay.

 

Certainly not for the £250 the Briggs & Stratton costs.

 

The 'average boater' will be paying £1000+ for the Honda EU22I equivalent.

 

 

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There was a boater in london had one like that, when we walked around St Pancras a few yeas ago, to make matters worse he moored partially under a bridge, with the genny under the bridge. He started it and went to the nearby bridge pub. Apparently after a few days of this the locals from the pub took matters into their own hands and threw both him and his genny into the cut and drove his boat away and put it on the next lock landing, there being nowhere else to moor. We could hear it at least half a mile away and we were in a big city, so noisy.

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46 minutes ago, David Mack said:

 

And I assume you can't buy anything that quiet which is portable and at a price the average boater is prepared to pay.

 

Very true, 7 years ago, when I last worked a standby generator plus its associated noise attenuation, fuel tankage etc was around £1,000 per kVA, for a typical 500-3000kVA  installation.

Edited by cuthound
Clarification
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