Electrical not my Forte'- AC 'Leakage'

[Tsho]

I'm an 80% self repairer; I own multiple boats and have for the last 15 years, I have my aptitudes and my weaknesses. Electrical is a weakness.

My new 'home' is a 42' Taiwanese Trawler. Just moved from San Diego to SF Bay, 500 mile journey was relatively uneventful after I spent a week plus going through the mechanicals.

My Marina (tenant her for 10+ years with various boats) says the new boat is leaking more than 65 milliamps when I have my AC turned on. Tested it with Marina, 'leak' registers the second I turn main AC breaker on, with ALL other breakers off. Bummer. I was hoping to isolate to a specific breaker.

I'm looking for advice on the troubleshooting process. 30AMP shore power. New shore power cord. Solid connections. I've started with the obvious, and have touched and tightened everything between shore power inlet and breaker panel. Also under the salon, I've tried to touch and tug every green and red wire.

Electrical is my weakness, the uber logic of it baffles me. I'm trying to find a pro.. but in the Bay Area that means weeks or months of wait...

Any suggestions on a process to start to identify the leak.

Oh, I do likely have bonding issues. The starboard side through hulls showed some halo-ing in the survey...

[Scott Berg]

This may help

https://gilwellbear.wordpress.com/20...sts-for-boats/

disclaimer: I do this for a living
Not asking to do yours
S

[Tsho]

Very helpful, thank you!

[Stu Jackson]

Originally Posted by Tsho

>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>
I'm trying to find a pro.. but in the Bay Area that means weeks or months of wait...

Any suggestions on a process to start to identify the leak. >>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>

Ryan Schofield, used to advertise in Latitude 38, good electrician.

Nigel Calder's Boatowners Manual has a good, long discussion of the issue.

[jmschmidt]

You didn't mention an isolation transformer on your shore power. Does this boat have one?

[Tsho]

Originally Posted by jmschmidt

You didn't mention an isolation transformer on your shore power. Does this boat have one?

If it does have one, I have yet to locate it. I've been mostly in smaller power boats and sail in my past, and have not worked with an isolation transformer before. At least I don't believe so.

Tom

[Qayaq]

Had this before on a Cruiser 42. If you take the earth off the circuit board card in the controller I think you will find it will stop. However it leaves the circuit board a bit unsafe but it might pin point the problem.

[Privilege]

You will likely have a huge problem with stray current eating up your underwater metals. Make sure that your zincs are good and monitor them often over the coming months. If you don't have them, the current will eat up your shafts, props and whatever other metals that you have below the water and it will happen quickly. If your zincs are only lasting a couple of months, apart from trying to locate the problem, you will need a galvanic isolator on your boat. This effectively blocks small current leaks from finding ground but still allows it in a major short. Some people would advocate just disconnecting the green wire on the AC system. This will also stop slow leaks finding the water and will solve your problem but then don't go around sticking your tongue on your sockets. Of course, not wanting to upset the electrical experts on the site, I DON'T recommend this course of action.

[Ahmet Erkan]

Originally Posted by jmschmidt

You didn't mention an isolation transformer on your shore power. Does this boat have one?

Very good point. If the main CB is energizing a defective isolation transformer or a power filter with excessively large Y capacitors this may cause 65mA of leakage current.
While you are trying to figure out what is energized when the main CB is closed and all other CBs are open, marina should allow you to use a UL approved overload protected 15A power strip and temporarily plug in your appliances. Buy a 15A power cord cut back and tape the ends of black and white power conductors and securely fasten the green conductor to your engine block, and plug it into the power strip and tape it in place this will make your boat safe until you figure out the root cause of the problem with your wiring.
You will also need a 30A mating connector or an adaptor plug to interface to your shore power cord.
All the best and be safe.
Ahmet

[Tsho]

Well, I learned a few things. None particularly encouraging.

- I'm really leaking power--the clamp meter is reading over 1A with the AC panel, inverter and outlets on. Only .1A with only the AC panel on, but still registering a leak.

- I do have a galvanic isolator installed. By replacing the butt connector that puts the GI inline with shore power and boat green wire, I am now leaking about .3A less than prior to that repair. (but still more than 1A).

- removing the green wire from the AC panel entirely does not change the leakage.

- I replaced the shore inlet connector connector at the boat, the AC rotary switch for Gen or AC (of off), and the main AC 30 Amp breaker with new. No change.

- My aft head outlet is showing a ground fault.

- I searched high and low for any very obvious wiring problems. My bonding looks like hell, and will need work between all thru hulls, etc (tomorrow's project) but I did not see any other obvious wiring faults.

I'll spend more time below deck redoing all of the bonding wires and connectors, and looking for more obvious wiring issues but am feeling close to stumped.

Thanks all!

[Tsho]

To close the loop on this discussion. Took a 2nd pair of eyes to confirm what is so often the case... "it's usually the simplest solution"...

After replacing many components, and chasing wiring all of the boat... this turned out to be the one wire that very early on looked suspicious to me--but that I didn't trace initially.

Looks like a residential electrician was on my boat. One 6 gauge (?!) wire that tied an Earth (green) to a Neutral (white) bus. Removed and problem solved. Learned a lot about the boat in the mean time.

Thanks everyone for your help.

T

[Ahmet Erkan]

Dear Tsho,
Five minutes after your original post Mr. Scott Berg responded and sent you a link with comprehensive and step by step instructions to test your boat for basic safety compliance. You confirmed it was helpful. It was clearly stated in one of the tests to disconnect the shore power cable from the pedestal, keep it connected at the boat and verify that the neutral terminal was not connected to ground terminal at the plug.
You should also perform the other basic safety tests recommended at Scott's website. For example the continuity check from the shore power plug ground pin to the engine block is very important. Also, use the diode check capability in your multimeter to verify the diodes in your galvanic isolator you said was present.
As long as the boats are in compliance with the basic safety checks electricity near water is very useful and very safe, otherwise people suddenly die.

[Tsho]

Originally Posted by Ahmet Erkan

Dear Tsho,
Five minutes after your original post Mr. Scott Berg responded and sent you a link with comprehensive and step by step instructions to test your boat for basic safety compliance. You confirmed it was helpful. It was clearly stated in one of the tests to disconnect the shore power cable from the pedestal, keep it connected at the boat and verify that the neutral terminal was not connected to ground terminal at the plug.
You should also perform the other basic safety tests recommended at Scott's website. For example the continuity check from the shore power plug ground pin to the engine block is very important. Also, use the diode check capability in your multimeter to verify the diodes in your galvanic isolator you said was present.
As long as the boats are in compliance with the basic safety checks electricity near water is very useful and very safe, otherwise people suddenly die.

Dear Ahmet,

I followed Mr. Scott Berg's very helpful link from step 1-completion. Those test confirmed that I had a neutral to ground connection. They also revealed several other issues, as did additional tests I performed not included in my posts. Finding *where* the issues were located was less the challenge, not finding out *what* the issues were. I did not make that clear, apparently. Thank you for help as well--if not your tone. Be well.

T

[Ahmet Erkan]

I am well, thank you.
OK what is wrong with my tone?
A fellow sailor brings his new boat to the marina.
The fellow sailor reports his shore power cable has greater than 65mA leakage current but only when he closes the main breaker thus the marina does not allow him to hook up his boat to the shore power. So thinking that the fellow sailor can't use his air conditioner, cook his meal or charge his computer etc. I suggest a totally safe, NEC, ABYC, ABS, UL etc compliant temporary shore power hook-up with parts readily available from local Walmart, Home Depot, Lowes etc for under $20.
When the fellow sailor is convinced he has solved his problem, and does not question the absurd data taht was provided in the previous repair steps, I just follow up recommending the fundamental electrical safety check of ground continuity, and a basic check of the galvanic isolator for preventing galvanic corrosion.
No BS, I just focus on my area of expertise and I never recommend an unsafe or improper procedure.
No sir, there is nothing wrong with my tone.
Ahmet