"geneb321" wrote in message
...
There is an excellent article on testing for grounding problems between
shore power and boat at: http://www.yandina.com/electrolysis.htm


I don't recommend following the instructions at that web site. Creating a
potential safety hazard so that you can eliminate galvanic corrosion is not
a good trade off in my book. You would also have to eliminate just about
every piece of 110 volt gear (TV, ice maker, battery charger, etc.) or come
up with elaborate ways of isolating them.

Rod

"Rod McInnis" wrote in message ...
"geneb321" wrote in message
...
There is an excellent article on testing for grounding problems between
shore power and boat at: http://www.yandina.com/electrolysis.htm


I don't recommend following the instructions at that web site. Creating a
potential safety hazard so that you can eliminate galvanic corrosion is not
a good trade off in my book. You would also have to eliminate just about
every piece of 110 volt gear (TV, ice maker, battery charger, etc.) or come
up with elaborate ways of isolating them.

Rod

I suggest that somebody develop an induction system similarto that
that was to be used with electric cars. No direct electrical
connection to the boat so we eliminate thjis problem.

On 21 Apr 2004 18:44:14 -0700, (Parallax)
wrote:

"Rod McInnis" wrote in message ...
"geneb321" wrote in message
...
There is an excellent article on testing for grounding problems between
shore power and boat at: http://www.yandina.com/electrolysis.htm


I don't recommend following the instructions at that web site. Creating a
potential safety hazard so that you can eliminate galvanic corrosion is not
a good trade off in my book. You would also have to eliminate just about
every piece of 110 volt gear (TV, ice maker, battery charger, etc.) or come
up with elaborate ways of isolating them.

Rod

I suggest that somebody develop an induction system similarto that
that was to be used with electric cars. No direct electrical
connection to the boat so we eliminate thjis problem.

There is such an induction system - called an "isolation transformer"
This provides the basis for an effective safety system.
Appreciable power ratings cost.

A poor man's approach, which unfortunately has limited power
capability is to join two similar mains transformers at their
secondary windings. The thoughput is then limited to the power
capability of one such secondary.
Example: take two step down transformers rated 120 / 24 volts 10 amps

Connect the 24 volt windings together.
Result, an isolated mains output limited to 240 watts ( = 24V X 10 A)

Brian W

On 21 Apr 2004 18:44:14 -0700, (Parallax)
wrote:

"Rod McInnis" wrote in message ...
"geneb321" wrote in message
...
There is an excellent article on testing for grounding problems between
shore power and boat at: http://www.yandina.com/electrolysis.htm


I don't recommend following the instructions at that web site. Creating a
potential safety hazard so that you can eliminate galvanic corrosion is not
a good trade off in my book. You would also have to eliminate just about
every piece of 110 volt gear (TV, ice maker, battery charger, etc.) or come
up with elaborate ways of isolating them.

Rod

I suggest that somebody develop an induction system similarto that
that was to be used with electric cars. No direct electrical
connection to the boat so we eliminate thjis problem.

There is such an induction system - called an "isolation transformer"
This provides the basis for an effective safety system.
Appreciable power ratings cost.

A poor man's approach, which unfortunately has limited power
capability is to join two similar mains transformers at their
secondary windings. The thoughput is then limited to the power
capability of one such secondary.
Example: take two step down transformers rated 120 / 24 volts 10 amps

Connect the 24 volt windings together.
Result, an isolated mains output limited to 240 watts ( = 24V X 10 A)

Brian W

"Rod McInnis" wrote in message ...
"geneb321" wrote in message
...
There is an excellent article on testing for grounding problems between
shore power and boat at: http://www.yandina.com/electrolysis.htm


I don't recommend following the instructions at that web site. Creating a
potential safety hazard so that you can eliminate galvanic corrosion is not
a good trade off in my book. You would also have to eliminate just about
every piece of 110 volt gear (TV, ice maker, battery charger, etc.) or come
up with elaborate ways of isolating them.

Rod

I suggest that somebody develop an induction system similarto that
that was to be used with electric cars. No direct electrical
connection to the boat so we eliminate thjis problem.

"geneb321" wrote in message
...
There is an excellent article on testing for grounding problems between
shore power and boat at: http://www.yandina.com/electrolysis.htm


I don't recommend following the instructions at that web site. Creating a
potential safety hazard so that you can eliminate galvanic corrosion is not
a good trade off in my book. You would also have to eliminate just about
every piece of 110 volt gear (TV, ice maker, battery charger, etc.) or come
up with elaborate ways of isolating them.

Rod

Thanks for the input from everyone. One thing that is puzzling here.
Each slip is a separate home run to a meter. None of the slips are
interconnected. Each is independent. If this is the case leakage from
other bots on the ground shouldn't affect my zincs. We are looking for
a source that is outside the AC connections. At least that is what I
beleive.


"geneb321" wrote in message ...
There is an excellent article on testing for grounding problems between
shore power and boat at: http://www.yandina.com/electrolysis.htm
Gene
SV Sea Gypsy

"Chuck Baier" wrote in message
om...
Our marina has a problem at some slips with stray current. Some of the
boats are loosing zincs at a fast rate while others are not. Looking
for some help in trying to resolve this and what kind of equipment
will I need. Thanks. Chuck

It will matter... if voltage is introduced to the water (from other
boats, bad dock wiring, etc) then it will flow to the fastest way back
to ground... all the grounded metal (boats, etc) around it.

Chuck Baier wrote:
Thanks for the input from everyone. One thing that is puzzling here.
Each slip is a separate home run to a meter. None of the slips are
interconnected. Each is independent. If this is the case leakage from
other bots on the ground shouldn't affect my zincs. We are looking for
a source that is outside the AC connections. At least that is what I
beleive.


"geneb321" wrote in message ...

There is an excellent article on testing for grounding problems between
shore power and boat at: http://www.yandina.com/electrolysis.htm
Gene
SV Sea Gypsy

"Chuck Baier" wrote in message
.com...

Our marina has a problem at some slips with stray current. Some of the
boats are loosing zincs at a fast rate while others are not. Looking
for some help in trying to resolve this and what kind of equipment
will I need. Thanks. Chuck

It will matter... if voltage is introduced to the water (from other
boats, bad dock wiring, etc) then it will flow to the fastest way back
to ground... all the grounded metal (boats, etc) around it.

Chuck Baier wrote:
Thanks for the input from everyone. One thing that is puzzling here.
Each slip is a separate home run to a meter. None of the slips are
interconnected. Each is independent. If this is the case leakage from
other bots on the ground shouldn't affect my zincs. We are looking for
a source that is outside the AC connections. At least that is what I
beleive.


"geneb321" wrote in message ...

There is an excellent article on testing for grounding problems between
shore power and boat at: http://www.yandina.com/electrolysis.htm
Gene
SV Sea Gypsy

"Chuck Baier" wrote in message
.com...

Our marina has a problem at some slips with stray current. Some of the
boats are loosing zincs at a fast rate while others are not. Looking
for some help in trying to resolve this and what kind of equipment
will I need. Thanks. Chuck

Here's one scenario.
The shore power distribution hardware carries a live 115 volt AC line,
a neutral line and a ground line.

As likely as not, the ground line is connected physically to the
neutral line at some closeby point. (For ALL slips)

Or if not, some misguided owner may connect his neutral lead to ground
return, with much the same effect.

This notional ground may have several volts imposed on it by the
voltage drop in the neutral return.
If you carry the ground on board to a through hull, this potential can
drive a current to the ACTUAL ground (below the water)

Brian W

On 21 Apr 2004 16:49:29 -0700, (Chuck Baier)
wrote:

Thanks for the input from everyone. One thing that is puzzling here.
Each slip is a separate home run to a meter. None of the slips are
interconnected. Each is independent. If this is the case leakage from
other bots on the ground shouldn't affect my zincs. We are looking for
a source that is outside the AC connections. At least that is what I
beleive.


"geneb321" wrote in message ...
There is an excellent article on testing for grounding problems between
shore power and boat at: http://www.yandina.com/electrolysis.htm
Gene
SV Sea Gypsy

"Chuck Baier" wrote in message
om...
Our marina has a problem at some slips with stray current. Some of the
boats are loosing zincs at a fast rate while others are not. Looking
for some help in trying to resolve this and what kind of equipment
will I need. Thanks. Chuck