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I have a 2016 SIG270 with Volvo Penta dual prop. Today, while working on boat we noticed a definite electric current in the prop when touched. The boat had main engine and house batteries ON, but the boat was out of the water on it's lift. We were in water standing on sandy bottom. Is it normal for there to be an electric current in the props and outdrive? We turned main engine and house batteries OFF, and electric current stopped. Normally we store boat out of water on lift with all batteries OFF.

Is the small electric current part of the corrosion protection system? All the anodes on boat are in good condition. 

Thanks,  Joe

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Your GFCI is N G !!!  Replace it......... Or the wiring somewhere has been jury rigged or corroded open.  Might not even be a GFCI feeding the dock outlets. It can drown / kill if the voltage increases for some reason.  NO more in water working on the boat until corrected.

The GFCI circuit breaker is / should be in a circuit breaker panel on land.  That protects pier / dock & boat from electrocuting anyone. Home DEpot C B is better than the marine junk. Land GFCI trip at 5 milliamps or less.  Marine GFCI are WAY HIGHER.    Stupid dangerous logic.

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14 hours ago, cyclops2 said:

Your GFCI is N G !!!  Replace it......... Or the wiring somewhere has been jury rigged or corroded open.  Might not even be a GFCI feeding the dock outlets. It can drown / kill if the voltage increases for some reason.  NO more in water working on the boat until corrected.

The GFCI circuit breaker is / should be in a circuit breaker panel on land.  That protects pier / dock & boat from electrocuting anyone. Home DEpot C B is better than the marine junk. Land GFCI trip at 5 milliamps or less.  Marine GFCI are WAY HIGHER.    Stupid dangerous logic.

They were at anchor with no AC power source.

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No, if you mean 'weren't anchored' to indicate the boat's anchor. Boat was on the lift, high and dry, shore power was ON and so were both main engine battery and house battery switches.

I read elsewhere that this is part of the corrosion protection system. I have a General Class FCC license and am knowledgable about electricity, but can't really understand how a mild, low voltage, low amp current would prevent corrosion, ie, electrolysis from 'stray current.'  A steady flow through the outdrive would render the outdrive somewhat if not completely impervious to  stray current from elsewhere that would slowly remove metal from the outdrive and props through electrolysis. Right?

This lift is at my house, and there are no other boats nearby as in a marina. One boat at perhaps 50' distance is neighbor's boat that is in the water and on shore power.

Unlikely there is 'stray current' from my lift's motors, because the boat sits on rubber ramps (part of the boat lift) and this provides insulation. Right?

Thanks for the comments. Much appreciated.

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A few thoughts:

- I assume with the Signature 270, there's shorepower.  If so, was it plugged in?

- If on the lift, is the boat electrically isolated or does any metal on the lift come in contact with any metal on the boat?  Should be no, so just confirming.

- Given the original post, and the fact no one went to the hospital, there is a stray 12 volt current. 

It's safe to say nobody on this blog is a big fan or water and electricity mixing.  If we focus on the spirit of what cyclops2 was trying to convey instead of the rant against some product difference and another greedy company, stay out of the water so nobody gets hurt. 

Given this is a newer boat with a problem that potentially has grave consequences, I'm sure the dealer would love to know and that he/she will provide very timely service and through assistance to rectify.  No business owner with a desire to stay in business when made aware of this type of problem will force anyone to wait in line.  Everybody knows water and electricity don't mix.  If it were me, I would though, before making the call, validate the second bullet.  (Yes, it's unlikely stray 12 volt current will have grave consequences, however, with water and electricity, the most conservative posture is beneficial.) 

   

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Ok, Roger that, Hatem. I'll look forward to your in-water test results for current at prop.

Chap243, I can try today see if current is present with shore power off. Yesterday, we turned both batteries OFF, and the current stopped. Shore power was still ON with no current at prop with batteries OFF. SO, this makes me think the current at the prop was from the boat's batteries.  Still, not sure what that means.

Thanks guys!!      /Joe

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FWIW. Saturday I poked around the transom while taking a break from the humidity and being cramped up in the space behind the helm.  Boat was fully out of the water up on the lift, shore power attached, two starting batteries and house battery on and I was standing in higher than mid-chest water.  Same active corrosion protection system.  Probably done this 15 times on this boat, and 30 or more on the Sunesta 264 (also with stainless duo-props and active corrosion protection).  Had my hands all over the props, lower units, etc.  No current whatsoever.  Please kindly consider getting some help.  You've ruled out the lift.  Messing with shore power isn't the best idea under the circumstances.  Your decision.  I'm off the high horse now.  

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To get a shock we need a voltage difference. How is the boat 12 volt POSITIVE & NEGATIVE connecting to your body ?

A 9 volt battery can sting your wet tongue nicely.  +  and -  are close together in a salty saliva. 

I thought the Cathodic power supply was GFCI protected also ? If not ? Or defective . That will create a  A C  potential between the prop & sandy ground in the water.

turn off power to doc & remove the dock plugs. If the shock stops ?  Bingo a Real electrician is needed

It can also be the battery chargers leaking A C voltage to the props.

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On 8/5/2018 at 1:39 PM, docdixon said:

I have a 2016 SIG270 with Volvo Penta dual prop. Today, while working on boat we noticed a definite electric current in the prop when touched. The boat had main engine and house batteries ON, but the boat was out of the water on it's lift. We were in water standing on sandy bottom. Is it normal for there to be an electric current in the props and outdrive? We turned main engine and house batteries OFF, and electric current stopped. Normally we store boat out of water on lift with all batteries OFF.

Is the small electric current part of the corrosion protection system? All the anodes on boat are in good condition. 

Thanks,  Joe

The shock must be A.C. Not D.C. The boat (of course) has a wiring problem that must be looked at.

Why A.C. He grounded himself to the same ground as the A.C. panel. He was not grounded to the D.C. side.  As to being in the water and lake water is the most dangerous to be in. Saltwater will disperse the current. As to why it stopped with the batteries turned off. Might have something to do with the on-board charger.

As Cyclops2 said, you have a bad GFCI or one is not in use. Or I am misunderstanding something!! 

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Ignoring safety, another reason to engage the dealer - your boat and engine/drive might still be within the warranty period. Not trying to create alarm or worry, but stray electric current isn't the best thing for bearings and gears. Depending on current intensity and time, pitting, erosion and line fretting can occur. Down the road if the drive fails and these symptoms are found on a bearing(s)/gear(s), and this is determined to be the cause of the failure, you'll have an easier time reaching an accommodation. Given you weren't harmed, this points to low voltage. Therefore, it's much more probable than not there is zero damage and risk to the drive.

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25 minutes ago, Curt said:

Ignoring safety, another reason to engage the dealer - your boat and engine/drive might still be within the warranty period. Not trying to create alarm or worry, but stray electric current isn't the best thing for bearings and gears. Depending on current intensity and time, pitting, erosion and line fretting can occur. Down the road if the drive fails and these symptoms are found on a bearing(s)/gear(s), and this is determined to be the cause of the failure, you'll have an easier time reaching an accommodation. Given you weren't harmed, this points to low voltage. Therefore, it's much more probable than not there is zero damage and risk to the drive.

Its not the voltage but the current you want to be considered with. A good point on going back to the dealership

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Roger that Hatem.

Chap dealer mechanic said no way is this the boat.

Electrician who installed shore power and lift said mild current at prop is not voltage leakage from shore power. We have a 5 milliamperes GFI in the dock. He advised there are so many grounded transformers on our island  that we have in effect created  a battery. So when person is grounded in salt water on sandy bottom, and touches the metal outdrive which is the ground for the boat, and there’s current in boats system you’ll feel a mild tingle. Nothing to worry about. We shut off all power to boat dock and still felt current, unless we turned all boat batteries off. Then no tingle. Hmmm. Way above my pay grade. 

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did you remove the dock plugs from the dock outlets ? So the boat is totally isolated from all land power voltages ?  Do the plug disconnects . With the batteries on.  Tingle stops ?

 13.5 vdc is the maximum  volts available. This eliminates any possible bad GFCI currents or battery charging currents. 

Note the boat metals may be tied to battery negative. The battery positive can get into the water by bare spots of + 12 vdc pump & float circuit wires in the wet bilge.

WE need to find out what is causing the tingle.......................... I HATE human bodies getting any shocks.

If the dock plugs are still in . The battery chargers are possibly leaking some ACV thru the chargers & into the battery posts. Then into the metal parts in the water.  Could still be the ACV.

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Have we all learned NOT to go into water near any docks with power outlets on them ?

Remember You can not see electricity in water. But it can tingle. Lucky...........Shock & cause drowning.............Stop the heart muscles & cause drowning.

FEAR ELECTRICTY NEAR WATER.

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Transformers ARE NOT A BATTERY. 

Most people consider a transformer a  ACV device.   A battery is considered a DCV device. To average electrical people.

Find another / different electrician.

The boat being on the lift RULES OUT DCV tingling you............. No complete path for current.    Back to the ACV.

WAs going to suggest turning off the power to the lift also. Is that a GFCI breaker also ?

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3 hours ago, docdixon said:

Roger that Hatem.

Chap dealer mechanic said no way is this the boat.

Electrician who installed shore power and lift said mild current at prop is not voltage leakage from shore power. We have a 5 milliamperes GFI in the dock. He advised there are so many grounded transformers on our island  that we have in effect created  a battery. So when person is grounded in salt water on sandy bottom, and touches the metal outdrive which is the ground for the boat, and there’s current in boats system you’ll feel a mild tingle. Nothing to worry about. We shut off all power to boat dock and still felt current, unless we turned all boat batteries off. Then no tingle. Hmmm. Way above my pay grade. 

I hope he is right, but I bet he is wrong. I would measure that voltage and current. As I mentioned that is A.C. voltage.

So what he is saying that A.C. on the hot side that he wired is leaking to the engine and drive. If that is the case, than the GFI should trip and its not. Than you step in the water and ground your self and you get shocked. And that is a battery a affect??? I bet your going though anodes too, or about to. That would be another clear sign that it is wired wrong.

Did he install a Galvanic Isolator ? Are you using a marine rated battery charger? This too, could be causing the problem. 

What you might have to, but I don't think so. Is A.C. current leaking into the sand and your touching the grounded boat. 

I would get a marine electrician (2nd set of eyes) and have it checked out before someone gets hurt. 

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What is a .......arch-fault breaker ?

 Just noticed that you have the GFCI at the dock............ WRONG !!!!!  It MUST be in the power panel on land. away from the water.  GOOD GRIEF !!!!!!!!!!!!!! Electrician  ??   is a complete danger to all people walking on a flooded dock . They would be swimming in in 120 vac electrified water............ FATAL.

Have a LICENSED LAND ELECTRIC COMPANY inspect & redo the dock wiring.

 

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What did I describe as previous testing ?  Do you read me & then rewrite what I say ? Is that your style  ?  

There is no such thing as a arch-fault breaker.  There is a ARC-FAULT BREAKER   ( AFCI  ).  Or a combined GFCI  &  AFCI  breaker. The NEC 2014 mandates them since then.  But I have not read the latest NEC codes on marine protection requirements. Will catch up on the good & bad of updating old wiring systems. 

If my medications allow retentive short term memory on a life threatening subject.

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The galvanic isolator only helps with leakage to a point. Nothing over 0.6 to 0.8 volts A.C. It will not pass D.C.

Something else too which I did not think of earlier. It was explained that "Electrician who installed shore power", so it was not factory. Was he a marine electrician that understands thing like the boats bonding system and galvanic isolator? 

Most electricians do not use the test button on a GFI to test it. If you use a "wiggy" tester that almost all of them carry. Its the type that is a solenoid voltmeter that are handy partly because the solenoid mechanism vibrates when a voltage is applied. Never tried with a Ohm's meter, but test between hot (the small slot) and ground, say the screw to the cover plate. The GFI should trip, because your pulling current from the hot side alone. Its to easy to do and its a true test of the outlet.

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