Electrical Leakage Checks On The Hard?

[zstine]

Originally Posted by Oceanride007

Its normal on ships to have earth lamps on every DC and AC circuit. They use meters now but lamps is easy to rig, the principle is that a the lamps are half brilliant normally, but when the test button is pressed, one will dim, the other will brighten. When set up, disconnect each circuit in turn, till you capture it. There should be a image attached.

If not there, Two lamps connected across the load, at the midpoint between the lamps, a test switch connects the circuit to the bonding system/hull.
If your battery negative is connected to Hull (Mine is) it may need to be disconnected for the test.

I understand the test circuit. With the test button is open, it is just 2 bulbs in series seeing 6V each, half brilliant. With the test button closed, you put a ground between them and one sees all 12V and the other 0V in an ideal world. With resistance in the wires, the second bulb may see some voltage depending on how much resistance there is in the wire... What I don't understand is how to use this to identify a fault. you say "When set up, disconnect each circuit in turn, till you capture it." capture what exactly? what am I looking for? Thanks!!

[zstine]

Originally Posted by kish

Corrosion Reference Electrode Product Specifications

Corrosion Reference Electrode and User's Guide
by ABYC-Certified Corrosion Experts

"
The Corrosion Reference Electrode is an extremely useful test and diagnostic tool that should be included within the toolbox of every boater and marina operator. When plugged into your digital multimeter you get answers to questions such as:

"Do I have enough zinc on my boat?"
"Are my shaft zincs still attached?"
"Is my bonding system working okay?"
"Are boats next to me eating my zincs?"
"Is my galvanic isolator working?"
"Is all of my electrical equipment installed correctly?"
"Do I have stray electrical currents either in my boat or at my dock?"
"Is my dock and/or marina operating at the correct corrosion potential?"
The user's guide is written and maintained by ABYC-certified corrosion experts, and includes test methods and reference tables that help you assess, diagnose and troubleshoot corrosion problems on your boat, yacht or dock.

"

I have a reference cell and tested last summer, but I want to check my fixes before I splash, hence this thread. There was No smoking gun, just a lot of little potential issues and I've done a lot of little fixes.. test results here..
http://www.cruisersforum.com/forums/...on-173804.html

[hzcruiser]

Originally Posted by Oceanride007

2nd attempt with the image.

Why is there a resistor?

A simple way to measure this would be hold the positive lead of a voltmeter to battery plus and the negative lead to the bonding wire. Compare that voltage with the battery voltage itself.
If you get 0 V to the bonding wire the battery is not bonded to the hull.

[Oceanride007]

So you have a Anode system that is electrically connected to the thru hulls and Rudder I assume the propshaft is only protected by the shaft anode.? But you are blowing a coating off your lead keel that is bonded to the Engine, that is electrically connected to battery Neg.! and your wasting a lot of zinc. Is all of this true.?

Thinking aloud, what is your resistance between bonding wire and battery negative, I'd bet its, low. Are any radios, earthed to that bonding wire, cose even if turned off the negative is not switched is it. Any other possible connections?, are we still on track if so, I fear next step is hard wire disconnections on the negative bus. The earth lamps will help out here because they'll tell you straight away.

[hard aground]

Do you have a shore cord plug in on the boat? You will also need an AC leakage current clamp on meter. eg Yokogawa 30031A. Plug in boat, clamp on meter, turn on circuits one by one while watching meter. When the meter is reading current check that circuit. After you fix that circuit keep checking the rest of your circuits. When you are done everything should be on and the meter should read 0A. Make sure your battery charger/water heater/etc. is actually operating when you turn on that particular circuit. Good luck.

[Oceanride007]

Heinz, No resistor only ship load and the resistance of the light bulbs.
Other way around, if you have a dead short between either batt poll and bond/hull the you have a dead short somewhere and no light illumination.

HA the leakage current that could cause Anode wear is way below what a clamp meter would read.

zstine, to identify the faulty circuit, all circuit have to be isolated one at a time until your lamps go back to half brilliance, you have found the circuit at fault.

In all my years as a Marine Engineer, these shorts were tracked down as a matter of high priority, as 2 faults on different voltage was major as it would cause CB trips, (think steering gear). Hull return is never used on board a commercial ship because of circulating currents would cause galvanic corrosion.

[zstine]

Originally Posted by Oceanride007

So you have a Anode system that is electrically connected to the thru hulls and Rudder I assume the propshaft is only protected by the shaft anode.? But you are blowing a coating off your lead keel that is bonded to the Engine, that is electrically connected to battery Neg.! and your wasting a lot of zinc. Is all of this true.?

Thinking aloud, what is your resistance between bonding wire and battery negative, I'd bet its, low. Are any radios, earthed to that bonding wire, cose even if turned off the negative is not switched is it. Any other possible connections?, are we still on track if so, I fear next step is hard wire disconnections on the negative bus. The earth lamps will help out here because they'll tell you straight away.

Not entirely true. My rudder, thru hulls and keel are all now floating. They are unprotected, no zinc. The keel was connected to the engine until the end of last season when I lifted the bond. The coating damage had been done before removing the bond to the engine and so I don't know what the effect of removing that connection is/was.. So, now the battery neg is connected to the engine/shaft via transmission. I haven't installed a shaft brush yet, on the to-do list. All DC negatives return to a terminal strip near the batteries, pass through a shunt for the monitor, then to the batteries without a switch. The engine bond is also connected to the same terminal strip as all the DC negative circuits connect, So in a sense, all DC loads are earthed to the engine bond. exactly like this pic, but with a shunt between the terminal strip and battery. I'm still not clear on how the Earth lamps will show a fault?

[zstine]

Originally Posted by Oceanride007

zstine, to identify the faulty circuit, all circuit have to be isolated one at a time until your lamps go back to half brilliance, you have found the circuit at fault.

So a faulty circuit would make both bulbs half brilliant as if there was no ground between them? .. I'm missing something .. I don't comprehend how a faulted circuit would have the effect of removing the earth ground plane in between the bulbs when the test button is closed. Even a dead short wouldn't raise the voltage in the earth ground plane that much, and I'm worried about a few tenths of a volt of leakage. not a short. I'm confused... if the circuit is faulty (like a bad bilge pump dumping current to bilge water), when you press the test button, the only difference I conceive is that the earth ground may have a few tenths of a volt on it, vice ~0V.

[Oceanride007]

zstine, I may have made a mistake at shooting my mouth off without understanding your system. My explanation relates to most but not all, for a start for Earth lamps yes you need something to connect it to.

So how is your anode connected to your vessel, how many. If all your thru hulls and rudder are floating, I assume then that all your anode/s is protecting is the shaft, even as you mentioned you don't have a slip rings yet. Its not much, how are your anode connected internally and to what.

[zstine]

Originally Posted by Oceanride007

zstine, I may have made a mistake at shooting my mouth off without understanding your system. My explanation relates to most but not all, for a start for Earth lamps yes you need something to connect it to.

So how is your anode connected to your vessel, how many. If all your thru hulls and rudder are floating, I assume then that all your anode/s is protecting is the shaft, even as you mentioned you don't have a slip rings yet. Its not much, how are your anode connected internally and to what.

The only Zinc I have is on the shaft and it only protects the shaft/prop right now. When I was blowing off the keel coating, the keel was connected to the engine/shaft and therefore, also the DC negative. I'm hoping the disconnection of the keel to engine bond will save my keel. would love to check that on the hard somehow before I splash.

[Oceanride007]

It does happen that at the Cathode under some circumstance of over protection Hydrogen bubbles can lift off your paint system. But your shaft anode is not going to do that, and I know little about protecting a lead keel.
In my opinion your rudder shaft needs protection, your thru hulls maybe and a bob strap to a Anode system.

[boatpoker]

Originally Posted by DeepFrz

Your DC ground and your bonding system should be completely separate. I'm not sure how your DC ground bus is set up but it should be the main ground, not your engine. Engine should have a ground lead to the DC ground bus. DC ground should not go to your keel.
https://www.westmarine.com/WestAdvis...unding-Systems

There are many, many issues in that article in direct contravention of ABYC Standards.

[zstine]

Originally Posted by boatpoker

There are many, many issues in that article in direct contravention of ABYC Standards.

I don't see anything in the Westmarine article and the ABYC picture you posted, which talks mostly to conductor sizing, that contradict. The westmarine article doesn't even mention anything about conductor size. I care about fixing and testing my boat and just making it ABYC compliant won't necessarily solve my problem, especially if I have a bad wire/component to find.

What I have yet to hear is any method in testing for leakage current while on the hard... I would imagine I could just check voltage on my keel and prop shaft to real earth ground and see if it is the same as I turn on and off DC systems?? I can get the data, but need some electrical guru to tell me it's meaning... and what data to look for.

[boatpoker]

Originally Posted by zstine

I don't see anything in the Westmarine article and the ABYC picture you posted, which talks mostly to conductor sizing, that contradict. The westmarine article doesn't even mention anything about conductor size. I care about fixing and testing my boat and just making it ABYC compliant won't necessarily solve my problem, especially if I have a bad wire/component to find.

What I have yet to hear is any method in testing for leakage current while on the hard... I would imagine I could just check voltage on my keel and prop shaft to real earth ground and see if it is the same as I turn on and off DC systems?? I can get the data, but need some electrical guru to tell me it's meaning... and what data to look for.

In the first section 11.16.2.5 thru 11.16.2.5.3 ABYC says lightning protection, cathodic bonding and static electricity grounding may be bonded. That is only one significant difference among many in that article.

Other than simple continuity testing nothing can be accomplished on the hard. You need to get to work with the reference cell when splashed.

[bletso]

I may have missed something. What is your keel made of? Can it be that with the keel and zincs connected together you have inadvertently set up a battery? i.e. dissimilar metals in an electrolyte connected together will have current flow and less noble metal zinc is being sacrificed to the water gods.