Reverse Polarity only when boat is on lift

[glenn property of pam]

Re: Reverse Polarity only when boat is on lift

NEUTRAL to GROUND = 6V..... this is higher that 1.5v indicating a failed isolator. The voltage on the ground may swing up even higher when other items are used on the boat.

Find the isolator

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

That's where I need help.

I've been told my boat doesn't have a galvanic isolator. Taking off the panel is a mess, have to take several things apart to even get behind there. Even then I wouldn't know what to look for... So I assume "whatever" is grounding to the water?

Nothing to do with the battery charger isolator?

Thanks

 

[glenn property of pam]

Re: Reverse Polarity only when boat is on lift

can you get to the back of where the shore power comes on to the boat. pictures would realy help.

mercury galvanic isolator - Yahoo! Image Search Results

look at the pics of isolators and see if you have anything that looks the same

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

I can take it back apart, is there anything "hot" in there as long as all power is off? There's a DC switch too, but I usually have that turned off by the main battery switches near the transom.

I found this which might be part of the problem:
"Think back to when I described where a GI gets installed? It goes in the GREEN SAFETY GROUND WIRE! So now what happens if one or both of those diodes get blown? NO SAFETY GROUND....! There were far to many incidences of boats with GI's that completely lost their safety ground connection to shore due to failed diodes. A single lightning strike on a boat a few docks away could take out half the GI's in the whole marina and folks rarely even noticed.. Couple this with the fact that many more boats are not wired, on-board, to current safety standards where the AC green/grounding wire is bonded to the ships DC grounding bus and this means metallic parts of AC devices could become "hot" in the event of a fault. Hot cases and metallic parts of your boat spell the potential for electrocution or death to swimmers by electric shock drowning. The problem is that without the safety ground the fault protection devices will not trip as they should. This = BAD !" Testing A Galvanic Isolator Photo Gallery by Compass Marine at pbase.com

I don't know why people would even put an isolator on their boat, I'd rather replace a prop than die... like I said, most people with boats in the water wouldn't have a clue this is even happening.

I also wrote Captain Rifkin Quality Marine Services, LLC to see if he might be interested in flying out to check this thing if I can't locate it behind the panel.

 

[dingbat]

Re: Reverse Polarity only when boat is on lift

OK, did the testing, the numbers seem to add up, albeit probably not the way they probably should...

Take your meter to the Shore Power Outlet and measure the voltages. SERIOUSLY!

HOT to NEUTRAL = 121V
HOT to GROUND = 121V
NEUTRAL to GROUND = 0V

The Shore Power Cable is Just an Extension Cord with a NEMA L5-30 on each end.
Now attach the Shore Power Cable to Shore Power only and measure the voltages on the other end.

HOT to NEUTRAL = 121V
HOT to GROUND = 121V
NEUTRAL to GROUND = 0V

Now attach the Shore Power Cable to the Boat still On the Lift.

The Standard 120 volt household outlet is officially designated as a NEMA 5-15.
The Round pin is GROUND.
The Smaller Blade is HOT
The larger Blade is NEUTRAL.

Take your meter to any 120v Outlet aboard the boat on the Lift and measure the voltages.

ON THE LIFT
HOT to NEUTRAL = 121V
HOT to GROUND = 115V
NEUTRAL to GROUND = 6V
I then measured from the bimini rail that I got shocked on, and there were the 6V (5. something). So the bad power cords must have thrown another 40V on the rail...

SO, I tested again IN THE WATER
HOT to NEUTRAL = 121V
HOT to GROUND = 121V
NEUTRAL to GROUND = 0V

I'm confused with your readings. An AC circuit has 3 wires, hot (wht), neutral (blk) and earth ground (grn). You should have 120 volts between hot (wht) and neutral (blk). You should have 0 volts between hot (wht) and ground (grn) and neutral (blk) and ground (grn).

Should read:
HOT to NEUTRAL = 121V
HOT to GROUND = 0V
NEUTRAL to GROUND = 0V

 

[GA_Boater]

Re: Reverse Polarity only when boat is on lift

I'm confused with your readings. An AC circuit has 3 wires, hot (wht), neutral (blk) and earth ground (grn). You should have 120 volts between hot (wht) and neutral (blk). You should have 0 volts between hot (wht) and ground (grn) and neutral (blk) and ground (grn).

Should read:
HOT to NEUTRAL = 121V
HOT to GROUND = 0V
NEUTRAL to GROUND = 0V

Are you sure about that?

 

[UncleWillie]

Re: Reverse Polarity only when boat is on lift

I'm confused with your readings. An AC circuit has 3 wires, hot (Wht), neutral (Blk) and earth ground (Grn). You should have 120 volts between hot (wht) and neutral (blk). You should have 0 volts between hot (wht) and ground (grn) and neutral (blk) and ground (grn).

Should read:
HOT to NEUTRAL = 121V
HOT to GROUND = 0V
NEUTRAL to GROUND = 0V

No, No No!

It Should read:
HOT to NEUTRAL = 120V = BLACK
HOT to GROUND = 120V = WHITE
NEUTRAL to GROUND = 0V = GREEN

AC Hot is BLACK!
DC Neutral (Negative) is commonly Black. With Red commonly Positive.
On newer boats, DC Neutral is YELLOW to avoid the confusion.

The AC Neutral (White) and the Ground (Green) are connected TOGETHER back at the circuit panel in the house.
Hot to either will read 120!

The Neutral/Ground Junction point in the panel is connected to a 10 foot long Ground Rod buried in the Earth/Soil/Dirt somewhere close to the circuit panel.

His Ground is 6 volt away from the Neutral, meaning they are NOT connected together anymore. There lies the problem!

 

[UncleWillie]

Re: Reverse Polarity only when boat is on lift

I can take it back apart, is there anything "hot" in there as long as all power is off? There's a DC switch too, but I usually have that turned off by the main battery switches near the transom.

I don't know why people would even put an isolator on their boat, I'd rather replace a prop than die... like I said, most people with boats in the water wouldn't have a clue this is even happening...

It is not about replacing a prop It about dissolving all your zincs every month or less and then the whole outdrive begins to dissolve. Want to buy a new Alpha-1 every year?

You have the MerChathode system that biases the zincs to 0.7 volts. Super Good!
Without the Isolator, the zincs would be shorted out through the shore power ground to 0.0 volts and do nothing.

Unplug the shore power plug. Without a running 120 volt generator on board. ALL 120 AC will now be gone and you will be safe to touch anything you want.
If the battery switch is on, 12 volt DC will still be present.

Start with Disconnecting the shore power from the receptacle on the Boat.
Start at the this Receptacle. Follow the green wire.
The first thing it is connected to is the isolator.
Easy, Breezy!


In the interest of Safety and not Scary drama. I should have mentioned this earlier.

Before you pick up any meter; Remove all jewelery. Rings, Watches, Bracelets, Necklaces, Everything, SERIOUSLY!
A Wedding ring across 120 volts or even 12 Volts DC will draw more AMPS than you can imagine.
The ring will instantly turn to vapor and explode in a fireball, searing your finger off and spraying your face with metal vapor. Nothing you ever want to see.
Bare skin just gives you a nasty shock that causes you to slam you elbow into the other wall.
Way better outcome!

 

[UncleWillie]

Re: Reverse Polarity only when boat is on lift

I just read the "How to test" link.
Those instructions will work fine.

As long as the Shore power plug is removed, you will not even need to remove either wire from the Isolator to test it.

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

"The Neutral/Ground Junction point in the panel is connected to a 10 foot long Ground Rod buried in the Earth/Soil/Dirt somewhere close to the circuit panel. His Ground is 6 volt away from the Neutral, meaning they are NOT connected together anymore. There lies the problem!"

Wait, are you saying the ground rod next to the power box on shore or in the house? I did notice the ones by the dock were jacked up, the one from the panel was barely touching the ground rod after the weekwacker hit it. The electrician was suppose to reconnect it when he was out, should 2 wires be wound together and attached to the rod? There's one wire (black I think) coming from the panel and the green coming from the dock, both were at one time connected to the rod. Will have to check tomorrow.

Thanks for the ring advice, that's what touched the bimini rail and thought my funny bone exploded...

 

[glenn property of pam]

Re: Reverse Polarity only when boat is on lift

you may have more than one grounding rod. The main one everyone has is next to the incoming power from the electrical company and will be near the meter.
As the dock has metal items on it and water is a conductor there may be extra ground rods installed near the dock.The rods are used to protect against lightning running from the dock to the house.
The neutral is only allowed to be tied to the ground at one point and that is at the main incoming service panel which is the one next the the electrical meter. (there may be exceptions to this rule but im not going in to that as we dont want to confuss you)
The tests you did shows that your home has no voltage on the ground plus a electricain tested it so that side is good. The test showed the cord is good and there no corrision on the terminals (they are new so it wouldnt be expected). The test showed the boat is the problem so thats where the ground is having a problem. You should have the electricain fix the ground rod near the panel but it will not fix the boat.

p.s if we are going to talk safety while using a meter my advise would be never to put the meter on ohms unless you have to and double check its on volts before testing and never hold the meter between you legs while using the probes (hang it up, stand it up, or on some models one probe clicks in the back of the meter to hold it). Having a meter pop in your hand is the start of a bad day, having it pop while its being held between your legs is the start of a bad life.

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

Mechanic came out yesterday to locate the isolator and said it's too hard to get to (estimated 5-6 hours to rip everything out to get to it, he said its 3 feet to the left of the panel behind the sink in the head), so he's ordering a new one and will cut the wires and mount it right behind the panel... so we won't be able to test the old one. Since there's 2 shore power cords, he said both grounds will be going to the one isolator, I guess this makes sense...

Will let you know if the new one resolve the RP issue.

***Update: The "Certified" Rinker Marina just called back and the mechanic NOW guarantees it's NOT the isolator, but the voltage gauge causing the problem. He is so convinced that he's going to replace the gauge and if it doesn't fix the problem, they'll put the old one back in and not charge anything. I asked if they can test the isolator (which I know they can), and they said you can't, they're just to protect your boat from other boat's stray currents. Too bad it didn't protect me from getting shocked! Whatever, I really didn't feel like arguing.

If the gauge doesn't fix it, I'm going to hand the mechanic the procedure to test Galvanic Isolators:


----------------------------------------------------------
1. Unplug the shore cord from the pedestal
2. Get access to the isolator if convenient. If not, bring the pedestal end of the shore cord aboard and use the ground pin/sleeve for one side of the isolator. Use a convenient ground on the boat for the other end of the isolator.
3. Set the digital voltmeter to the Diode Test function.
4. Attach the leads across the diode. If it’s working properly and has a capacitor, you will see the voltage begin to climb as the capacitor charges. It should stop at about 1 volt or so if everything is working properly (the range can be 0.85 to 1.1v, depending on the characteristics of the meter). If it keeps going well past 1 volt, one or both of the diodes in that direction are open and you are just charging the capacitor.
5. Before switching the leads, short the isolator to discharge the capacitor to avoid damage to the meter.
6. Now repeat step 4 with the leads swapped to test the other pair of diodes.

Notes:

1. If there is no capacitor, the reading will instantly jump to about 1 volt. Some early isolators were made without capacitors. Otherwise, the capacitor is open circuited.
2. If the voltage stabilizes at about 0.5volts, one of the diodes in that pair is shorted.
3. If the voltage reads 0volts, both diodes in one direction are shorted, or the capacitor is shorted.
4. If there is no capacitor or it is open, and one or both diodes are open, the meter will read OL, or open circuit (no reading) in the direction being tested.

 

[UncleWillie]

Re: Reverse Polarity only when boat is on lift

What a nightmare!

I am Betting against the Voltage meter Idea.
Wen you got the initial shock that started all this; Was the voltmeter turned ON?

If the meter were leaking currents to ground; Which is what it does when it is turned ON;
The Isolator Would/Should be delivering those currents to Ground and Neutralizing them; Which it isn't.
Keep an eye on these guys!

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

Good question, I can't remember if the gauge was toggled on or off, just remember the shore power was on.

Maybe before he comes I'll try measuring ground to neutral on board with the meter ON and OFF


View Boat Photos - YachtWorld.com Photo 21 of 25 shows the panel which looks almost identical to mine. The voltage gauge is in the upper left (the white rectangle). The toggle switch just to the right of the gauge when you click up for MAIN or down for AIR CONDITIONING the red RP light comes on. In the middle (I assume the gauge is off) the RP lights go off.

 

[UncleWillie]

Re: Reverse Polarity only when boat is on lift

Now I get it.

Above, You can select the Port Or Starboard Shore power Inlet Jack.
Below that, you select if you are running off of Shore power or the Generator.

Other than the Volt meter, there is NO Shore Power OR Air Conditioner selection.

With the Meter OFF, it is out of the picture.

But, be sure to turn ON a bunch of On Board AC devices when measuring for the Ground voltage.
You need to create the possibility of generating a leakage current.
If everything is off, there will not be any.
If you are observant, you might even find the culprit.

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

OK, I tested the volts neutral to ground with shore power on and the voltage gauge off (in the center), still got around 5V in the GFI outlet in galley. Turned the voltage gauge ON (pushed it up), got around 46V neutral to ground (had to push the multimeter probes around inside quite a bit), and also 46V from boat bimini rails to dock (decided to test before touching this time). I pulled out the gfi outlet and didn't see anything strange, it's just 2 large thick (1/2 inch) white wires tied to the back of the gfi unit, the unit comes out in one piece and hard to see the individual wires.

Will let you know what happens when the gauge is replaced.

 

[UncleWillie]

Re: Reverse Polarity only when boat is on lift

Can you tell if the Gage is wired Hot to Neutral, or Hot to Ground?
Putting in a new gauge with the same wiring will give the same results.

If the Gage returns to Neutral (White), it should have no effect on the Ground Voltage floating.

If the Gage returns to Ground (Green), it's measurement current, ~0.001 amp will raise a Floating Ground way off of 0.0.
And 0.001 amps will give you a good tingle!

If the Isolator were working, the 0.001 amps would be shunted to shore power ground and you would not be having these issues.
You should not even have the 5 volts with the Volt meter OFF! Anything over 2 volt is a problem!

Mechanic came out yesterday to locate the isolator and said it's too hard to get to (estimated 5-6 hours to rip everything out to get to it, he said its 3 feet to the left of the panel behind the sink in the head), so he's ordering a new one and will cut the wires and mount it right behind the panel... so we won't be able to test the old one. Since there's 2 shore power cords, he said both grounds will be going to the one isolator, I guess this makes sense...

Will let you know if the new one resolve the RP issue.

***Update: The "Certified" Rinker Marina just called back and the mechanic NOW guarantees it's NOT the isolator, but the voltage gauge causing the problem. He is so convinced that he's going to replace the gauge and if it doesn't fix the problem, they'll put the old one back in and not charge anything. I asked if they can test the isolator (which I know they can), and they said you can't, they're just to protect your boat from other boat's stray currents. Too bad it didn't protect me from getting shocked! Whatever, I really didn't feel like arguing.

Hold your Ground! (Pun!)
I missed the part where we went from "Order a New One" to "It's Not the Isolator".
How was that determined?
Is sound a lot like, "If I can't get to it easily, it must be something else!" :mmph:

Have we CONFIRMED that the ground wire from the Shore Power connectors Actually Have Continuity to the Isolator?
It could still just be a loose wire!

While we are Putzing around waiting for the Tech to get the Gage;
Does it make any difference to the ground voltage, if you select the Port, or Starboard Shore Power Breakers?

With the shore power connectors Removed;
Measure, OHM, between the two ground pins on the Shore Power Connectors. Are they connected together?

... It's just 2 large thick (1/2 inch) white wires tied to the back of the GFI unit...

I will assume you are referring to some 1/2" White, Flat, Romex Cable and not a pair of 1/2" Round Battery Type Cables.

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

I know the gauge is at least connected to green since that's the wire he cut the first time. Is that not correct?

"With the shore power connectors Removed;
Measure, OHM, between the two ground pins on the Shore Power Connectors. Are they connected together?"

Are you referring to the shore power inlet on the boat or the power cord? Both inlets are right next to each other on the port side.

Yes, it was flat white romex cable.

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

I agree 100% - the problem is that are no "marine electricians" in the Ozarks, and all "land electricians" I called refuse to step on boats. I have called 9 marine mechanics:

- 3 showed up: 2 said the boat was fine, the 1 coming back is going to replace the gauge but said the isolator is too hard to get too (quoted $800 to rip the boat apart to get to it).

- 4 called back but never showed after several calls, well, 1 did say to call back after Memorial weekend

- 2 never returned call after leaving several messages.

The one ABYC certified "marine electrician" I hired 100 miles away ended up being just a marine surveyor who didn't even look behind the panel, eventually "thought" tree pollen on the boat might be causing 45V of static to build up on the rails. Never once did he mention isolator. He said it was "impossible" for the volts to be on the bimini rail. He also told me to buy a new battery charger and ice maker, both of which ended up being fine. I found more myself by following instructions from UncleWillie and others on this board.

The Ozarks are saturated with very good engine / drive mechanics, but any true marine electricians wanting to relocate could probably name their price...

 

[Thalasso]

Re: Reverse Polarity only when boat is on lift

You need to contact a certified ABYC electrician.As for it said boat wiring isn't all that complicated that any electrician should be able to do it, is totally false. AC on a boat isn't like wiring a house. Getting shocked when out of the water means you are the return path. When in the water (fresh) the return path is the water.Check all bonding wires.

Here is a vidieo from a certified ABYC eletrican. Start at the 17min mark
http://youtu.be/O7-s_mdEPb0

I just remembered you have this posted on another site also.
smac999 is correct in his reply