Help with shore power earthing! (i think..)

> silly ole sailorman wasnt totally wrong then

It looks that way! Thank you for your input, that is what is great about these types of forums, as sometimes there is more than one answer! /forums/images/graemlins/wink.gif
 
If your boat had the mains fitted at the factory the ac and dc would not be bonded. If you look at the owners manual and go to the back and look at the wiring diagrams you will see they dont bond them. When I found mine was not bonded I checked with Jeanneau and 2 other boat builders and they all said the same that it used to be done but not now.
 
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clever ole sailorman wasnt wrong then


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OK then - dont rub it in.

BTW I'm prety sure that my old Sealine had the AC earth bonded to the DC system. I found this out whilst using an earthed soldering iron to solder a 24v connection - bang!
 
I wouldnt connect my shorepower earth to my boat ground. That leaves anyone elses earthing problems a route right to your boat engine.
 
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Nigel Calder's view on things.

[/ QUOTE ] Thanks for that link.

I have, until recently, insisted that the shorepower earth, the DC negative and the ships earth (anodes etc) should all be bonded together on the grounds that ISO13297, and ABYC and CE standards required it.

Then I was given a link to ISO 13297 and discovered that it was not required provided an RCD was fitted protecting the whole shorepower installation.

Now I discover that ABYC and ISO 13297 differ on this!

I have only had time to scan through Calder's article but when I have more time it is going to make for some interesting reading.
 
Didn't think of looking at the boats handbook.... sometimes I'm dangerous when left alone!

I will have a scan through the wiring diagrams, thanks! Then if all confirmed my next job maybe to disconnect the earth lead from the RCD unit.... trouble is Nick Calder is very well respected and does rather suggest otherwise. Oh what to do..

/forums/images/graemlins/confused.gif
 
I think your priority should be to establish the reasons why your charger tripped the RCD and blew its internal fuse. If that turns out to be due to a faulty charger then that's dealt with otherwise you have a problem with your wiring somewhere that must be rectified.

Earlier in the thread you were considering ditching the charger and going for something more sophisticated. I would have thought a Sterling ProBudget was an excellent choice for a boat with a relatively simple electrical system and only one battery.

Whether or not you connect the shorepower earth link to your 12v DC is up to you. There are arguments, you now realise, for doing so but with an RCD installed it is not necessary according to ISO13297. With just an outboard engine and presumably no cathodic protection system (unless I've missed that) the arguments in favour of it are pretty small as the RCD should provide all the protection you need.

Do nothing is the easy option!

I do not think I have seen a reference to a galvanic isolator. If your DC negative is connected to the shorepower earth then your outboard engine may be a risk of galvanic corrosion if one is not fitted
 
Thanks VicS for your clear summing up of the situation.

I have come to the same conclusion. I believe the charger was probably faulty, I did buy it new, through eBay, for just £30,... so I think it was good value. Perhaps it got dropped during transit.. However the retailer is sending me a new unit which I will full test prior to fitting.

My outboard does have a large anode fitted which has just been replaced as part of the service and the old anode was very corroded. Although now I am hanging a large second hand anode I recovered from the boat yard over the side of the boat, connected to the engine which will save a lot of wear on those fitted to the engine. I cannot warrant a galvanic isolator... it is just a small boat after all!

Thank you
 
If the rate of wastage of your engine anode is due to galvanic corrosion resulting from the shorepower earth being bonded to the DC negative a galvanic isolator may well pay for its self over a few years.
Not bonding the two together is the low cost solution. Saves the cost of the GI and should reduce the anode wastage rate.
Not replaced my outboard engine anode in 25 years, but then the engine is lifted clear of the water when not in use.
 
I am thoughtful of your second option,

>Not bonding the two together is the low cost solution. Saves the cost of the GI and should reduce the anode wastage rate.

This is what I may well end up doing.

My engine I lift clear of the water, but the bracket and hydraulic pump is left in the water, as the cost of replacing the pump I found out is £3500 I am keen to keep a handle on corrosion!
 
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