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

Hi Chuck,

Best solution is an isolation transformer but they are not cheap. Next
best solution is a galvanic isolator. We have one on each of our
30A shorepower circuits and it is pretty effective.

Doug
s/v Callista

"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

Thanks Doug, but I am looking for info on how to track down the source.


"Doug Dotson" wrote in message ...
Hi Chuck,

Best solution is an isolation transformer but they are not cheap. Next
best solution is a galvanic isolator. We have one on each of our
30A shorepower circuits and it is pretty effective.

Doug
s/v Callista

"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

Too bad it's the wrong kind of electrolysis, otherwise you could get a bunch
of ladies to hang on the dock/dip their legs in the water/and get rid of
those little tiny annoying hairs.


"Chuck Baier" wrote in message
om
Thanks Doug, but I am looking for info on how to track down the
source.


"Doug Dotson" wrote in message
...
Hi Chuck,

Best solution is an isolation transformer but they are not cheap.
Next best solution is a galvanic isolator. We have one on each of our
30A shorepower circuits and it is pretty effective.

Doug
s/v Callista

"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

"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

When I was evaluating the effectiveness of those zinc "fish" anodes that you
hang from the boat, I used a clamp-on DC ammeter to measure the current on
the fish's wire, and on my AC shore-power cable (I don't have an isolation
xfmr or diodes). You might measure the DC currents on all the boats'
shore-power cables to see if there is a pattern or a particular offender.
Ideally, I suppose there wouldn't be any DC (or AC) current measured if you
pass the power cable through the ammeter clamp. Take several turns of the
cable through the meter clamp to increase the measurement sensitivity. You
should probably also check any other shore-connections while you're at it
(cable TV, phone, etc).

I've only tried this on my own boat, but I am assuming that any massive
stray current has to come from a shore connection. The polarity of the
measured current is probably important to figuring out what is going on. Of
course, this is all just a theory...

Regards,
Paul
s/v VALIS

In my neighborhood, (30 years old+) the current comes from broken wires
hanging in the water from old dock lights going through metal
conduit.... Many old commercial docks have similar issues.



Paul wrote:
"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


When I was evaluating the effectiveness of those zinc "fish" anodes that you
hang from the boat, I used a clamp-on DC ammeter to measure the current on
the fish's wire, and on my AC shore-power cable (I don't have an isolation
xfmr or diodes). You might measure the DC currents on all the boats'
shore-power cables to see if there is a pattern or a particular offender.
Ideally, I suppose there wouldn't be any DC (or AC) current measured if you
pass the power cable through the ammeter clamp. Take several turns of the
cable through the meter clamp to increase the measurement sensitivity. You
should probably also check any other shore-connections while you're at it
(cable TV, phone, etc).

I've only tried this on my own boat, but I am assuming that any massive
stray current has to come from a shore connection. The polarity of the
measured current is probably important to figuring out what is going on. Of
course, this is all just a theory...

Regards,
Paul
s/v VALIS

Chuck -

I am assuming you are plugged in to the dock. The neutral line creates a
common connection between all the boats in the marina. Although it is a AC
circuit the circuit itself really doesn't care if it is carrying AC or DC
current, as long as a circuit is completed.

On your shore power feed neutral connect a amp meter and measure both the AC
and the DC current. If it isn't your boat you will see current flowing from
your shore connection to your boat. You can either unplug all the boats in the
marina and systematically replug boats and see their individual effect on the
DC current flowing through you neutral leg of go to each boat and check them
individually. This is the easiet way of locating a DC fault on someone elses
boat. Strongly reccomend getting permission before un plugging anyone though!

A/C faults, although less of a zinc loss problem can be a bit more difficult to
find. The same method works though. I have found that most AC faults are
either due to miswired shore cables, internal boat wiring or most
common.........mis wired shoreside power system.

Let me know if this helps.

Dave

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.



(Dajofa) wrote in message ...
Chuck -

I am assuming you are plugged in to the dock. The neutral line creates a
common connection between all the boats in the marina. Although it is a AC
circuit the circuit itself really doesn't care if it is carrying AC or DC
current, as long as a circuit is completed.

On your shore power feed neutral connect a amp meter and measure both the AC
and the DC current. If it isn't your boat you will see current flowing from
your shore connection to your boat. You can either unplug all the boats in the
marina and systematically replug boats and see their individual effect on the
DC current flowing through you neutral leg of go to each boat and check them
individually. This is the easiet way of locating a DC fault on someone elses
boat. Strongly reccomend getting permission before un plugging anyone though!

A/C faults, although less of a zinc loss problem can be a bit more difficult to
find. The same method works though. I have found that most AC faults are
either due to miswired shore cables, internal boat wiring or most
common.........mis wired shoreside power system.

Let me know if this helps.

Dave

The commons are all connected together. Heres the senerio :

Boat A has a misconnected wire charging the boats system
neutral.............Boat A is plugged into the dock..........current from boat
A travels through neutral leg, which are tied together due to code and into
boat B shore cable..........hence into boat B......through the bonding
system..........through the water.........back to boat A. Zincs from boat B
are plated onto boat A.

Dave

(Dajofa) wrote in
:

The commons are all connected together. Heres the senerio :

Boat A has a misconnected wire charging the boats system
neutral.............Boat A is plugged into the dock..........current
from boat A travels through neutral leg, which are tied together due
to code and into boat B shore cable..........hence into boat
B......through the bonding system..........through the
water.........back to boat A. Zincs from boat B are plated onto boat
A.

Dave


Hmm....while you're traveling from marina to marina....you could put a
little DC power supply between boat neutral and marina neutral, replating
your zincs and underwater appendages with noone the wiser overnight.....

Not an entirely bad concept!

Just kidding, guys. Pay no attention to that humming sound in our
bilge....(c;

Larry