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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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20 hours ago, 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.

So let me understand this because I think there is a bit of confusion going on.  The boat was on the lift and out of the water with house and engine batteries switch in the "ON" position while you were standing in the water on a sandy bottom behind it and when you touched the props, you could feel a little current in the them, yes?  You weren't anchored and touching the props?

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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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22 hours ago, docdixon said:

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.

Ok, just wanted to be sure it was on the lift and not anchored since there was a bit of confusion that it was the latter.  Which does raise a valid point which is - would you still get the current in the props if you were anchored and not on the lift?  Then you'd be able to isolate the issue to the boat and not the lift causing the stray current.

22 hours ago, docdixon said:

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?

I would agree with the 2nd part of that statement, but not necessarily the first part that it would be part of the corrosion system.  It sounds more like a ground issue and I don't believe you should feel any current at the props, even for corrosion protection and even with batteries on.  But I could be wrong.

22 hours ago, Curt said:

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

Yes, he said shore power was on as well as all batteries.

22 hours ago, Curt said:

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

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.) 

Except if it's a lift issue, metal contact somewhere like you eluded to earlier.  Agree completely that extreme caution needs to be taken here.  For now, he shouldn't connect any shore power while the boat is on the lift.  As a matter of fact, turn the breaker switch to the  lift off until you figure out what is happening.  12vt is much less of a tickler than 120 or 240.

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22 hours ago, 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

Headed to the beach in about an hour from now.  We always back up to the shore and anchor and chill in the water and beach etc.  I will shut down the engine, put all batteries on (and I have 3, brand new Group 31 all-purpose batteries for both house and starting) and I will check the duoprop to see if there is any current.  I don't mind getting a little tickle in the pickle....been in the construction busy for 30+ years and have been zapped with much worst than 12vts on several occasions, so no big deal.  I know my anti-corrosion is working and anodes were new ones installed in the beginning of the season and will check and see if I get any current and let you know.  I want to check the bottom and outdrive for growth anyway.  It doesn't sound right that you can feel any current and my guess is you have some short somewhere or something isn't grounded properly for some reason or another.  Unless plans change in the next few hours or so, I'll let you know how it turns out.

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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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2 hours ago, docdixon said:

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

Ok, Joe.  Currently anchored on the beach and just checked props with all batteries on and no zingalinga whatsoever, my friend.  Just like Curt said.  Ok, off into the water and I'll check in later! :)

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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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2 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. 

Fascinating.  It actually makes sense.  The electrician most likely put the GFI circuit at the lift on an arch-fault breaker also.  So if there was anything coming to it from that shorepower that was causing any shorting or improper grounding, the arch fault breaker is very sensitive that it would most likely sense it and automatically trip the breaker, if the GFI doesn't trip first.  Might be worth asking him if the GFI is on an arch-fault breaker and if it isn't if that would help.

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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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Yeah, even though the electrician's theory is quite plausible that there is massive stray current in the water from all the nearby transformers being grounded, and that might cause that bit of current to go through the body and to the powered boat through the props while making that connection standing in the sand and water, the question is whether it should or not.  Presuming the boat is wired correctly and the galvanic protection is also working correctly, there shouldn't be any conduit at the props, right?  But we need to make sure the power to the lift motor and the GFI are not the problem, first.

Joe, you need to do a few things, please.

1) Is the GFI outlet's interrupter at the lift working?  There should be a test button right on the receptacle, push it in and see if the outlet trips.

2) Is the GFI powered from a subpanel near the dock and is that subpanel grounded into the ground near the water, as in this pic here so that it's grounded back to the main panel at the house?

10114d1241411213-proper-wiring-outlets-d

3) Or is there no subpanel at all at the dock?  This is important.  Is it outlet and lift motor wired directly from the main panel to the lift?  I HIGHLY doubt a licensed electrician would do that but I don't know him and so you never know, so I'll ask anyway. 

4) Are any of the conduits carrying the wiring to the lift motor submerged in the water?  Or are they all running above water and attached to the dock somehow?  Are they all inside water-tight conduits?  This is all important stuff just to be sure the wiring to the dock and lift is done correctly and we can rule out faulty dock & lift wiring. 

5) Lastly, did you try what @Chap243 suggested?  Leave all the batteries on in the boat but unplug shore power, turn off the breaker to the GFI outlet (preferably the main at the house that feeds the subpanel at the dock/lift) so there is no power coming to the outlet and lift motor and nothing is grounded near the lift or grounded to the boat from the lift.  THEN give the props another quick touch while you're in the water with all batteries on.  Don't bear-hug them, please! lol  Just keep touching and letting go quickly until you're sure that you're still getting a tingle or not.  This will should isolate the issue from the dock & lift being improperly wired or grounded and that there is bare contact to the boat from that AC current.

6) If you're still getting current with the lift completely unpowered, then there probably is an issue with the DC wiring on the boat itself because even if you're creating the ground between the stray current in the water from all those grounded transformers to the props, the props shouldn't be connected to any of the boat's electrical system unless the galvanic corrosion is not properly grounded. 

That's where you would need to start unless someone thinks I'm wrong that the galvanic protection system to the drive shouldn't be creating that DC connection to the stray AC in the water.  It should be isolated from the props, hence the galvanic isolator, yes?  No?

 

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