JohnL
New member
Can anybody help with how to earth a portable generator when used onboard on a mooring? Also how are fixed generators earthed onboard? Thanks.
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AC.earth again.
- Thread starter JohnL
- Start date
Mudplugger
New member
John, being a total incompetent PC user, unable to provide you with the correct link..butm if you go to www.reading-college.ac.uk/marine/MarineEO1.html, you should find all the info you are looking for. Section ME11.
<hr width=100% size=1>Tony W.
<hr width=100% size=1>Tony W.
JohnL
New member
Hi Tony not very good with computers myself, tried that address got plenty of courses but alas no info, thanks for trying JohnL
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Vara
Active member
Try<A target="_blank" HREF=http://www.reading-college.ac.uk/marine/cover.html>HERE</A>I think thats what you are after.
<hr width=100% size=1>If it can't be fixed with a lump hammer dont fit it!
<hr width=100% size=1>If it can't be fixed with a lump hammer dont fit it!
JohnL
New member
THanks thats what I was looking for but I am even more confused now it seems earthing is all down to opinion rather than fact.
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Vara
Active member
I agree I've been monitoring this topic for ages and I've come to the conclusion that if you've got lots of volts on the boat you need to don rubber boots, suit and gloves,hang a sign on the mast saying keep away "Danger of death" and replace all metal under water at three monthly intervals./forums/images/icons/frown.gif
But then there seem to be thousands of boats persevering with no problems.
<hr width=100% size=1>If it can't be fixed with a lump hammer dont fit it!
But then there seem to be thousands of boats persevering with no problems.
<hr width=100% size=1>If it can't be fixed with a lump hammer dont fit it!
JohnL
New member
My boat spends most of the season on a mooring,the last few seasons I have started to venture further away from home so ocasionally it would be nice to use mains lecy, so I read what the PBO expert said ie.connect earth to 12v neg. fit galvanic isolator[sold by his company]. A member of our boat club who is a working electrician [who happens to have wired up the local marina]said as my boat is plastic it is not required to connect earth to 12v neg. He will aslo sell me at cost price quality RCDs sockets etc. to do the installation and check it when I have done the job. Who should I put my trust in?
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jillym
New member
Good god you lot need shaking by the throat, as it seems everyone else is shaking you by the wallet...
Doesn't matter what your boat is made of, you are protecting the metal bits of your boat from electrolytic action, hence a SACRIFICIAL ANODE. Right - ALL your metal bits should be tagged to 12volt earth and hence directly to your anode.
The galvanic isolator comes in when you need to earth your mains supply. You need to connect the earth of your 230 volt into one side of the isolator and the other to the anode (which is, of course, your 12volt earth).
The reason why you do this is because the earth on the mains is always floating around a few millivolts to a volt, which puts a potential on your anode and makes it dissolve fairly rapidly. The ba****ds who really get me are the guys who don't put an isolator in at all and connect straight to the anode, as the poor bugger next door with his aluminium boat will testify.
OK... next question?... hurry up or I'll start charging £500 a day...
Tony.
Doesn't matter what your boat is made of, you are protecting the metal bits of your boat from electrolytic action, hence a SACRIFICIAL ANODE. Right - ALL your metal bits should be tagged to 12volt earth and hence directly to your anode.
The galvanic isolator comes in when you need to earth your mains supply. You need to connect the earth of your 230 volt into one side of the isolator and the other to the anode (which is, of course, your 12volt earth).
The reason why you do this is because the earth on the mains is always floating around a few millivolts to a volt, which puts a potential on your anode and makes it dissolve fairly rapidly. The ba****ds who really get me are the guys who don't put an isolator in at all and connect straight to the anode, as the poor bugger next door with his aluminium boat will testify.
OK... next question?... hurry up or I'll start charging £500 a day...
Tony.
Bergman
New member
Re: Confused
Not entirely clear about the volts on the mains earth.
Where do they come from?
Are they positive or negative?
If the mains earth is connected to boat earth why is boat next door bothered?
If the isolator has mains earth and boat earth connected to it which earth is used by boat?
If boat earth how does it connect to actual earth?
Equally how does mains earth connect to actual earth and is it a different actual earth to the boat earth?
Is the anode earth?
What if you have more than one anode?
When you say all metal bits should be connected to anode do you mean mast and rigging as well?
Not entirely clear about the volts on the mains earth.
Where do they come from?
Are they positive or negative?
If the mains earth is connected to boat earth why is boat next door bothered?
If the isolator has mains earth and boat earth connected to it which earth is used by boat?
If boat earth how does it connect to actual earth?
Equally how does mains earth connect to actual earth and is it a different actual earth to the boat earth?
Is the anode earth?
What if you have more than one anode?
When you say all metal bits should be connected to anode do you mean mast and rigging as well?
jillym
New member
Re: Confused
Volts on the main earth - because the resistance to earth on a normally earthed mains circuit is not perfectly zero, as in a 12volt battery system, (a controlled circuit), you will always get a voltage drop across that resistance and hence a very small floating voltage at your earth terminal.
They can be positive or negative, but since your galvanic isolator only is concerned with current flow away from your faulty circuit, you only need be concerned with positive.
The water around your anode is ionised by this floating voltage also and can affect the exposed underwater metalwork of the boat next door that is exposed to that ionisation.
Boat earth is used by the boat, as the isolator, depending on type, can put the mains earth at a 1.2 - 2.4 volt potential higher than boat earth.
It connects to the actual earth through the water. Again we are talking imperfect connections. All you need worry about is using your battery negative (earth) as your reference point. Ignore what the outside world is doing at that point.
The next point I have already answered above.
Yes, the anode is earth, irrelevant to the amount of anodes you have because they should all be electrically bonded together anyway if you did the job right.
Mast and rigging ends up being one unit as they are electrically inseperrable. I would have thought most yachts would have had an earthing tag anyway to prevent static buildup, much like large antenna.
So do I get the job to fit your isolator? /forums/images/graemlins/smile.gif
Volts on the main earth - because the resistance to earth on a normally earthed mains circuit is not perfectly zero, as in a 12volt battery system, (a controlled circuit), you will always get a voltage drop across that resistance and hence a very small floating voltage at your earth terminal.
They can be positive or negative, but since your galvanic isolator only is concerned with current flow away from your faulty circuit, you only need be concerned with positive.
The water around your anode is ionised by this floating voltage also and can affect the exposed underwater metalwork of the boat next door that is exposed to that ionisation.
Boat earth is used by the boat, as the isolator, depending on type, can put the mains earth at a 1.2 - 2.4 volt potential higher than boat earth.
It connects to the actual earth through the water. Again we are talking imperfect connections. All you need worry about is using your battery negative (earth) as your reference point. Ignore what the outside world is doing at that point.
The next point I have already answered above.
Yes, the anode is earth, irrelevant to the amount of anodes you have because they should all be electrically bonded together anyway if you did the job right.
Mast and rigging ends up being one unit as they are electrically inseperrable. I would have thought most yachts would have had an earthing tag anyway to prevent static buildup, much like large antenna.
So do I get the job to fit your isolator? /forums/images/graemlins/smile.gif