Nice Post Mark. Thanks

"markvictor" wrote in message
oups.com...
OK Marc,
These are the facts: first,on your incoming shorepower ground,you
would take care of any "stray current" problems caused by the marina or
other boats by installing a galvanic isolator....sometimes called a
zinc saver...almost all in-water boats made today have them installed
OEM...Second, your AC ground absolutely SHOULD be connected to the DC
ground buss, at 1 location only, to prevent ground loops....Why? Some
of these other posters have forgotten that just because you are not
connected to shore power,does not mean there is no AC power
present....ie.gensets and inverters....A gfi will do absolutely
nothing if there is no true earth ground, and if away from the dock,
that ground is seawater,via the ship ground(shaft, bonding system,
thru-hulls etc. Without that AC ground connection, you can become part
of the ground circuit if a fault occurs. That said, you should have a
seperate buss for each of the following: a neg. DC buss, a ship's
GROUND buss, and an AC ground buss...Note that the DC neg buss is for
connecting dc equipment to battery negative, the ship's GROUND buss is
for bonding all equipment and machinery and the protective anodes
together. Why connect the two? because in the event of a bad neg. DC
connection, say to an engine block, it prevents The DC current from
seeking an alternate path to the starter etc through seawater and the
bonding system itself. Therefore there should be 1 bond between the neg
DC and the ship's ground buss, and 1 bond between the AC ground buss
and either 1)neg DC buss, or 2) (preferred) Ship's ground buss. This is
not debateable or optional....it is absolutely necessary for
safety...Period.
If you have problems with rapid zinc consumption, you need to do a
complete corrosion survey with the proper equipment to determine the
source of the problem. Disconnecting the bond is like turning up the
stereo to make an engine noise go away...Someone else remarked about
the NEC and metal enclosures and sparks...He is wrong! each breaker IS
ignition protected...they don't use metal enclosures due to weight and
corrosion issues...This is a BOAT not a BUILDING, he needs to
familiarize himself with ABYC and Lloyd's Standards, they are the
applicable codes, and in almost all cases more stringent than the
NEC.,but written for the marine environment, not sitting on a piece of
dirt... Your SSB antenna better not be grounded or you'll cook your
radio the first time you send modulation.
SSB signals bounce off ground(called a counterpoise) which is seawater
connected by an RF ground, your bonding and thru hull system, a steel
hull, a metal fuel tank, or a dynaplate. This reflects the ssb signal
skyward. Marc, do it once and do it right...remember that your boat is
your total life support system when you're at sea... you can't walk out
the front door when there's a problem....think about that before taking
shortcuts or cutting corners to save money.
And not to stir up things, but I can tell you with certainty.....Listen
to Chuck, and forget
anything that Larry posted....Chuck is right on target,and knows
boats.....Guys like Larry are
responsible for a large portion of my income...
I have no problem correcting mistakes at $85.00/hour.. I'm not spouting
steam at you, I have over 25 years in the marine industry primarily in
electrical and electronics and plenty of schools and certs. It's
cheaper to do it right! Good Luck!
markvictor

Thanks John,
I hate to see people get screwed up by bad info..
One of the most common things I hear on service calls is "my buddy
hooked it up for me" or "my buddy said all I had to do was..."
I hate to tell them, but he's not their buddy, he's MY buddy!
Sad but true.....
markvictor