Marine electricians

[alanporter]

Are there no marine electricians on this forum ? I posted a request for advice on 15 July <Bonding,etc> and didn't get a single response. I suppose if I had posted some ridiculous nonsense subject I would have had dozens of replies. Ah well !

<hr width=100% size=1>Alan Porter

 

[jbate]

Do you have a problem with galvanic corrosion?
The american Yacht and Boat Council ABYC reccomends tying the AC and DC ground/negative to a common bus and to the ground plate/ground. The main reason is actually for shock prevention, rather than for reducing galvanic corrosion. AC stray will not cause galvanic corrosion.
One of the main 'drivers' for the choice of bonding arrangement is likely to be common practice and 'what works' in your local marina - hot marina, aluminium boats, active marina protection systems ... etc.
I recommend an article by Ed Sherman in Professional Boatbuilder, no. 82, may 2003. I can send you a copy if you want to message me your contact details.
Regards,
JB.




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[Paulka]

Either there are no specialists on this subject, or there are as many opinions as there are specialist!
;-)

Here my 2 pennies:
- through-hulls are usually completely isolated from each other, as well as from any further inmersed parts, thus not endangered by elctrolysis. Let them alone.
- cooling water through-hull is no exception, unless its connected to the engine by some sort of uninterrupted metalic pipe (cooper etc.) Let it alone in both cases.
- 12V - 120V : some "experts" recommend to connect the -12V to the shore power earth. I don't see the point either, specially if, as recommended as well, a "galvanic isolator" is inserted between both, .... to block galvanic corrosion!

What I would insist on, in any case, is to protect yourself from the effects of 120/240 V faulty system, feeding your "boat network" through a 15ma (or less) differential (or ground fault) circuit breaker.

I am sure many experts will now show up an explain why the above is wrong!

.... But keep your differential CB, and keep checking the earth connection.

BTW it's how my own boat is wired, without any problem since nearly 25 years.

Good luck.

Paul



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[malcp]

I found this article by searching the www using Google with "galvanic isolation marine". It seems to cover what you are after and much more . .
http://www.sailmail.com/grounds.htm

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[Abigail]

I am no electrician. IMHO, if I was, that I might not always answer questions on this forum for free. I am constantly amazed and grateful at how many professionals of various kinds are generous with their information and skills on these bulletin boards - but I don't think they have to be ...

<hr width=100% size=1>Sarah&Pip

 

[BrendanS]

also holiday and boating season, so not everyone is on here as regularly as during the winter months

<hr width=100% size=1>Err, let me know if Depsol enters the forum, I'll go and hide

 

[dick_james]

Agree isolated fittings should be left alone but the reason for connecting shore ground to battery neg. has nothing to do with galvanic corrosion. It's to tie the 12v stuff to earth and not allow it to float up to 240v potential

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[alanporter]

Thank you for your replies, everyone. Much appreciated.

<hr width=100% size=1>Alan Porter

 

[alanporter]

Abigail. Isn't the purpose of these forums to allow the members to share their expertise and experience with each other ? I wouldn't dream of expecting to be paid, even though my normal professional fees are considerably higher than an electrician's.

<hr width=100% size=1>Alan Porter

 

[brianrunyard]

Maybe you're being a little impatient, not everyone logs into the forum everyday this time of year, some actually go boating!

<hr width=100% size=1>Brian
http://homepage.ntlworld.com/brunyard