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Old 01-08-2016, 03:46 PM   #1
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Simple ESD detector???

The Electrolysis check for Swift Trawler Owners thread by CeeBee was a great read, with lots of expert input and new things to learn.

I kept waiting for someone to point to a simple little gadget, maybe a digital probe or reacting strip of something, that one could quickly dip in the water around the boat to detect ESD. If there is enough electrical leakage to tingle a diver, it must be detectable.

Nothing was suggested and I know they make expensive ones for semiconductor labs but I can't find anything for or use.

Is there such a thing?
If not, IMO there is an opportunity for someone.
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Old 01-08-2016, 04:09 PM   #2
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I was thinking of a similar test for looking for DC leakage through the ground. I would think on the DC side, you could turn off shore power at the breaker and then unplug the cable on the boat side. Putting a voltmeter between the ground in the power cable and the ground on the boat plug, you should be able to see the potential difference by measuring VDC. I wonder if the same technique for finding AC flowing through the ground between the boat and shore.

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Old 01-08-2016, 04:15 PM   #3
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There are quite a few, ranging from your volt meter and a reference electrode probe (about $75-$110) all the way up to built in sensors with displays on the console and alerts when things go out of tolerances.

The reference electrode is a silver / silver chloride half cell that you drop into the water and once it stabilizes will read the current balance / imbalance in the water. The ground wire from your test meter goes to a known good ground on your boat bonding system. If your zincs are depleted, it will show that, as well as if someone else has a wiring problem on their boat near you.

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Old 01-08-2016, 04:25 PM   #4
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Here's a reference silver/silver-chloride (Ag/AgCl) electrode you would use with your DVM for $125.

Corrosion Reference Electrode Product Specifications
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Old 01-08-2016, 04:31 PM   #5
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For AC...the simple test is a clamp meter around the whole power cord...if more power is going in than coming out it will register if you clamp meter is sensitive enough.

If you have a zero reading...no loss to the water.

I believe BoatUS has an article containing a few simple tests as this.
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Old 01-08-2016, 04:40 PM   #6
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psneeld: But how about the guy next door?
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Old 01-08-2016, 04:40 PM   #7
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OK.
So, is there any way a generator, running on a boat with all chain rode, could discharge current to the water?
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Old 01-08-2016, 05:08 PM   #8
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Quote:
Originally Posted by Larry M View Post
psneeld: But how about the guy next door?
Check his...with a clamp meter it is non-invasive and takes 5 seconds.

Do the whole dock...

I'm just not sure that it would detect low enough that it catch all leaks...but certainly an amp or more...I would have to check my meters specs.
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Old 01-08-2016, 09:45 PM   #9
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Can't clamp a cable wth 2 conductors - you need to buy the attachment that splits the cable so you can clamp each conductor.
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Old 01-08-2016, 10:09 PM   #10
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Incorrect I believe. Read the article or any guide. Clamp all conductors and look for zero...if so...no leakage.

f you want amperage of a leg then yes, split.
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Old 01-09-2016, 06:18 AM   #11
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Quote:
Originally Posted by psneeld View Post
Incorrect I believe. Read the article or any guide. Clamp all conductors and look for zero...if so...no leakage.

f you want amperage of a leg then yes, split.
Correct except if the leakage is coming back to shore via the green ground wire of the cable. If so it will also read zero clamped around the whole cable.
The easiest place to read individual conductor currents is where the shore cable receptacle is connected inside the boat or at the SHORE-OFF-GEN switch.
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Old 01-09-2016, 07:39 AM   #12
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but if going back to shore via the green cable..fortunately no threat to swimmers even though still incorrect aboard vessel.

Then a check of individual feeds, then circuits, then items needs to be done.
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Old 01-09-2016, 10:59 AM   #13
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I am with Psneeld on this.

My understanding is as follows:
Using a true RMS amp meter around the entire 30 amp 120V shore power cord should read ZERO amps.

Any value above zero will on the ground wire. This will indicate some fault on the boat, not good.

Even though items on the boat are on, with no leakage to ground, zero amps will be the correct reading. As all three conductors are being measured at the same time, the amps measured on the hot wire will be cancelled out by the amps on the neutral wire as they are out of phase with each other by 180.

As it has been said many times, consult a pro if you have any doubts.

As to the original posters question, Would be a great tool to have.
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Old 01-09-2016, 11:14 AM   #14
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psneld, you must have a far better clamp on ammeter than I do since what you're saying won't work. you have to clamp a single conductor at a time, and the accuracy is no where near good enough to detect a small current leak.
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Old 01-09-2016, 11:18 AM   #15
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Quote:
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psneld, you must have a far better clamp on ammeter than I do since what you're saying won't work. you have to clamp a single conductor at a time, and the accuracy is no where near good enough to detect a small current leak.
Just going on what was suggested by boating expert writers that so many here tout about.

As I said...clamp on meter sensitivity is important...and for this test you do the whole power cord...not each conductor....you can argue with this all you want but I am passing along what was printed in several places. Clamping one conductor at a time works but then you have to do the math....clamping the whole wire...the meter does the math.

BoatUS.com Search Results

From BoatUS article
Analyzing Boatside Water-ShockHazardsJim ShaferDavid RifkinIBEX, October 12, 2007

•How can we test for current leaking into the water?
•An AC clamp meter that can resolve to 2 decimal places will do the trick
•While running as many AC loads as practical clamp the whole shore cord
•Any reading represents the current that is missing (i.e. not coming back in the shore cord)
•This missing current can only be going one place, into the WATER
•Where is this current coming
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Old 01-09-2016, 04:36 PM   #16
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Marine corrosion survey

Clamp amp use


Read these.

Not the last word but one explains how to set up for testing of electrical leakage in the water.

The other how and why to clamp the entire electrical cord.
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