[C320-list] Grounding and Bonding

[Warren Updike]

I am a curious person and in no way an engineer of any sort. I rely on
others with vastly more knowledge and experience than I.  My main boating
source is "Boatowner's Mechanical and Electrical Manual," 3rd edition, by
Nigel Calder.  You can find this in any boat store or on Amazon.com.  For
me, it is an indispensible reference.

That said, the whole subject of AC onboard boats is a complicated subject
and one that is not well understood even by some "experts," certainly not
me.  Nigel makes it clear that the AC-to-DC common ground does not solve all
problems; but, it is better than the alternatives.  The following is without
regard to whether a galvanic isolator, isolation transformer, GFCB, GFCI, or
xxyz is installed:
	"...it is a DAD IDEA (emphasis his) to break the AC-to-DC ground
connection.  If this is done, protection against ground faults, particularly
for swimmer in the water, becomes dependent on the proper operation of the
(device)..."  He goes on to talk about the failure rate of various devices.

So, there you have it.  What the devices don't protect against is their own
failure, and failure of other equipment and wires onboard that can allow
current to get to where we don't want it to go.  

Warren & Pattie Updike
1994 C320 #62 "Warr De Mar"

-----Original Message-----
From: Kaare Wold [mailto:sailor3952 at charter.net] 
Sent: Wednesday, January 16, 2013 5:29 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Grounding and Bonding

Pardon my ignorance, but isn't this the function of the galvanic isolator? 
There is one installed on our boat, Sheet Music.   Being new to our boat, 
hull 945, (and this great group)  it was my understanding that this device
protects you from neighboring stray current.  I have to admit (being a
welding engineer) that my knowledge of technical electrical systems is
limited.  Thanks for any education on the subject.
Kaare & Mary Wold
Sheet Music,  #945
----- Original Message -----
From: "Warren Updike" <wupdike at hotmail.com>
To: <C320-List at Catalina320.com>
Sent: Wednesday, January 16, 2013 4:12 PM
Subject: Re: [C320-list] Grounding and Bonding


> I've checked the wiring diagrams in my owner's manual, and they don't 
> indicate a cross-connect between the AC ground and DC negative busses.
> Nigel Calder's book, "Boatowner's Mechanical and Electrical Manual," 
> 3rd edition, has very extensive coverage on the subject.
>
> This is most important for boats that sit in a slip connected to shore 
> power.  Even with AC power on the boat turned off, you can still be a 
> victim of galvanic corrosion or worse from neighboring boats.
>
> It's not an easy subject to understand; but, there are years of 
> experience behind the ABYC recommendation to tie the AC ground to the DC
negative.
>
> Warren & Pattie Updike
> 1994 C320 #62 "Warr De Mar"
>
> -----Original Message-----
> From: Jerry Mickelson [mailto:jerrymick320 at comcast.net]
> Sent: Tuesday, January 15, 2013 3:25 PM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] Grounding and Bonding
>
> Warren,
> If I remember correctly, I do not think my were and I connected the 
> two negative buss bars behind the electrical panel.  Will check for 
> sure next time I am down to the boat.
> Jerry
> 1994 #118
>
>
>