Reverse Polarity only when boat is on lift

[BoatingLOZ]

I've had 5 mechanics to my dock and no luck trying to figure this out.

When my 2004 Rinker 342 is in the water everything's fine, but when it's on the boat lift and not touching the water the reverse polarity light comes on when either the MAIN or Air Conditioning shore power cords are connected and switched on. Once the boat touches the water the light immediately goes off. We've torn the boat apart, checked main panel connections, battery charger, all the green wires we could easily find, and an electrician said the dock and shore power are fine. It's a private dock.

Some background. The problem was identified originally when I got shocked by 40V whenever I touched the bimini rails (I have no idea how snce those should just be screwed into fiberglass!) 2 brand new shore power cords eventually solved that problem, but the reverse polarity issue still exisits. Not sure if they're even related.


Any ideas or suggestions would be greatly appreciated!

 

[glenn property of pam]

Re: Reverse Polarity only when boat is on lift

welcome.

the reverse polarity light also works as a "you have power on the ground light". Grats on getting a electricain to check things even if he didnt find anything.

There is a ground isolator between the dock ground and your boat that may have failed and will need to be located and tested (a electricain should be able to test that the boat ground is equal to the dock ground when plugged in). It sounds like the ground is not being made from the previous problem but just in case also have the ground at the boat lift checked because if it has a bad ground then it will try to use the boat as a ground path while on the lift. If the boat has a ground problem it will use the water and anything it can find in the water to ground out which is why the light will go out and can hurt someone swimming in the area as the water becomes a electrical field.

A good electricain will measure between neutral and ground on the boat if it reads higher than 1.5v then the isolator should be closed.

p.s the isolator is on the boat and should be the first place the ground wire goes to before it goes to the main panel

 

[glenn property of pam]

Re: Reverse Polarity only when boat is on lift

"The problem was identified originally when I got shocked by 40V whenever I touched the bimini rails (I have no idea how snce those should just be screwed into fiberglass!)"

code says anything metal must be bonded on the boat which will also include the negative dc side. So you had 40 volts on the ground when you got shocked

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

So all boats with shore power have ground isolators? It's not optional equipment like Galvanic Isolator? I will call the mechanic and electrician tomorrow but wanted to make sure I speak their speak, i.e. "you need to check the ground isolator." The boat has a mercathode system w/zincs on each drive, but I'm pretty sure no Galvanic Isolator.

Any idea how the bimini rails could become electrified? I replaced a nav light last summer and remember the entire housing just about falling apart when I removed the plastic over, wonder if something might be touching something it shouldn't be?

Thanks again

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

The electrician measured 40 volts AC from the rail of the boat to the dock. I grabbed the bimini rail to climb on the boat and when I touched the metal frame of the dock is when I got shocked.

Actually a marine surveyor said he measured 40 volts DC and 30 volts AC at the same time. But he also said the battery charger was fried which it wasn't. You don't even want to know his theory about the rail shock...

This thing has been frustrating, but there's got to be an answer. It probably just hasn't hit the $1000 mark yet, then it will be fixed, lol.

 

[UncleWillie]

Re: Reverse Polarity only when boat is on lift

Ground Isolator = Galvanic Isolator. Same thing.

This is NOT a Nuisance issue!

You are using the water to complete the ground.
You are going to disintegrate your zincs, and the zincs of all the boats around you.
You are going to corrode your out-drive at an accelerated rate.
AND you are going to electrocute any one in the water near the boat!
YOU Damn near electrocuted yourself when you touched the Bimini Rail.
You need to realize this is deadly serious and must be fixed!

NOW! Let's get serious!
Make no assumptions that anything correct.

The Shore Power outlet is officially designated as a NEMA L5-30. (if it Isn't, Speak up)
The Bent Blade is GROUND
The Larger Blade is HOT
The Smaller Blade is NEUTRAL

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

HOT to NEUTRAL = _____ ?
HOT to GROUND = _______ ?
NEUTRAL to GROUND = ______?

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 = _____ ?
HOT to GROUND = _______ ?
NEUTRAL to GROUND = ______?

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.

HOT to NEUTRAL = _____ ?
HOT to GROUND = _______ ?
NEUTRAL to GROUND = ______?

When we get the results we can move forward from there.

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

OK, I'll call someone back out. The problem here is land electricians won't touch boats, and every mechanic I've called just says if it works in the water, then everything's fine, I'm having a hard time getting anyone to dig into the electrical panel, and I don't know squat about electronics. I discovered the cables were bad just by trial and error.

I did notice that both the MAIN and Air Condition voltage gauge shows around 90 volts while boat is in the air, but correctly shows 110 in the water....one mechanic just cut a green wire to the volt gauge and suspects the gauge needs replaced (he's probably who I'll end up calling back). One mechanic tested a few diodes and never showed back up, one mechanic came out and tinkered with the battery charger and said the boat was perfectly safe to operate, 2 mechanics never showed after several calls, and the marine surveyor (recommended by ABYC) thought the stray current was from all the pollen on the boat, no joke. The surveyor also thought AC and DC were both coming over the shore power cord until the dock electrician corrected him. And all of them said the bimini rails should never get electrified since they're just screwed into fiberglass.

Had it been bottom painted and in the water year round like every other boat around me, the RP light "problem" would have never been found. Makes you wonder how many boats might have a similar problem.

I'll try the green wire cutter guy again, but I'm seriously ready to sell this thing!

Thank you for listening...

 

[Grub54891]

Re: Reverse Polarity only when boat is on lift

Might not be an easy job depending on boat size,but can you remove the boat from the lift,up on land,and plug er in and test? You say other boats are around you,could they be the problem? Another test to preform,you can take your meter connect to a ground,dangle the postitve lead in the water and see if there is any voltage around the dock.I did that once troubleshooting one and found higher readings by the next boat.,repaired that one and everything was ok. That repair was no shocking but corrosion,anodes being eaten up rather quickly,but still might help you out.
Grub

 

[UncleWillie]

Re: Reverse Polarity only when boat is on lift

You or someone with basic skills needs to actually measure the voltages.

Anyone that thinks cutting the green ground wires is going to fix anything is someone to stay far away from!

A real electrician will have no problem finding this problem.
We already know for sure that the Boat's Ground/Bonding wiring between the AC and DC systems
are NOT attached to the Shore Power Ground.
That is a given based on your symptoms. The only question is where.

The panel meter is showing 90 volts because the other 30 is on the ground lead!

When you say the "Reverse Polarity Light" comes on; do the "Normal Power" indicators go OFF?
Or are all Three ON?
I would love to come over and solve it; Where is Osage Beach?

 

[Splat]

Re: Reverse Polarity only when boat is on lift

Unclewillie is thinking the same thing I am. Same problem as the thread last week about getting shocked while the boat is on the trailer. Open neutral. Any electrician would have this running through their mind as the first thing to check.

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

- The Voltage Gauge has a toggle switch, up for MAIN, down for AIR CONDITIONING.

- The Shore Power / Generator pole switchs on the main panel, you move left for generator or right to Shore Power, there's a plate in the middle to prevent the gen from providing power same time as shore power.

When you flip the shore power switches on the main panel (there's also one for MAIN and one for AIR CONDITIONING), the green power light comes on. Only when you toggle up or down to read the voltage gauge will the red RP light come on. If you leave the toggle switch in the middle the green power light stays on and the red RP light goes off.

Osage Beach = ZIP 65065. I've called 2 more people, waiting to hear back.

 

[UncleWillie]

Re: Reverse Polarity only when boat is on lift

Apparently the Gauge measures to Ground instead of neutral.
The meter's current is raising the floating ground above zero and so only reads 90 volts differential.

The differential voltage between the Floating Ground and the Neutral is what is illuminating the "Reverse Polarity" lamp.
The neutral and the ground are/should be connected together way back at the main power panel on shore so the should not be any voltage potential between them.
This is not the case in your situation.
Your ground on the boat does not make it back to the ground rod at the shore power main panel as it should.

If you have a MerCathode System you almost certainly have a Ground/Galvanic Isolator and it probably has a problem.
Start there. Place a meter across it. If you see more than 3 volts; it is Dead.

-------------------------------------------------------------------
I am sure every one in Missouri knows where Osage Beach is.
It is a big planet, I was going to guess Florida.
Suggestion: Make your location read "Osage Beach, MO"

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

OK, added this to the list to check. Got a very good land electrician coming tomorrow, who also knows boats, recommended by several people. He invented some machine that detects stray currents in water around docks, actually going to install one on my dock tomorrow.

I'm also going to look at the spotlight, the wire goes through a hold drilled into the bow rails, maybe something got hot. I remember it was accidently left on for a couple hours last fall.

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

No shows today, what's new. Trying mechanic # 9 tomorrow and Called back # 7 said he'd be back tonight (wasn't) or tomorrow morning. I'd really like # 7 to show since he seems good.

 

[UncleWillie]

Re: Reverse Polarity only when boat is on lift

If you have a meter we would be glad to talk you through it.

The measuring is easy, the interpreting is were people have the problem.
You measure, we interpret.

 

[glenn property of pam]

Re: Reverse Polarity only when boat is on lift

im with unclewillie.

Unplug the boat then look at where the boat plugs in and follow the green wire until you come across a box or a silver tube that the green is attached to. If you can find the box where the green wire from the boat and the green from shore meet then the test is easy. Finding where they hide the box is the fun part

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

I do have a meter but is it safe to stick the 2 prongs in anything at the dock or boat at the same time? That's my only concern. Both cords for shore power are 30 AMP. If it's safe I can do it pretty fast, just wasn't sure what needs to be on or off.

I used a little thing I got from Menards to plug into each outlet. They all showed a green light in the middle which is good. No reverse polarity, ground problem etc. I simply plugged it into each AC outlet on the boat. Just concerned about going around touching live plugs with a meter. This WILL BE SOLVED! Surveyor never called back, but there's another mechanic that's 2 weeks out, he thinks maybe the defective shore cords might have fried the isolator and sent volts to a bad ground somewhere. Gonna keep hounding him until he shows. The problem at the lake is everyone is getting $200 to go and start up boats, so they don't want to waste time on something like this. FYI, there are over 50,000 registered boats at Lake of the Ozarks. Middle of January I could probably get 10 people out within 24 hours...

 

[UncleWillie]

Re: Reverse Polarity only when boat is on lift

All voltage measurements WILL be with the Power ON!

As long as you keep your fingers off of any exposed live connectors and don't do anything blatantly stupid,
like shorting out something; It is relatively safe to touch a Meter, set to VOLTS, to ANY Two terminals,
or in ANY sockets that are under 600 volts, with the POWER ON.


Does your Idiot Tester (And I say that Lovingly, I own two) have three lights?
1. Power Good
2. Ground Good
3. Reverse Polarity

I normally expect to see Two lights ON not just One.
Does it indicate the same in the kitchen in the house?

 

[BoatingLOZ]

Re: Reverse Polarity only when boat is on lift

I used this one on the dock and boat (all outlets tested correct, the bottom scenario with just the middle light on), didn't test anything in the house yet

http://www.menards.com/main/electri...-circuit-ground-analyzer/p-1460509-c-6452.htm

Update: went around the house and garage, all tested fine. The house is about 100 yards from the dock. Tomorrow I'll do the multimeter readings that you wanted.

The mechanic that's 2 weeks out (the one that thought the defective shore cords might have fried the isolator and sent volts to a bad ground) also wants to look at the shore power inlet on the boat itself, he said the pressure of the cords hanging 8 ft in the air might have pulled something loose. He also said to keep the shore power off, since if the boat is only getting 90 volts while on the lift, that can jack up the electronics. I had been keeping the battery charger and refers/ice maker on in the air.

 

[BoatingLOZ]

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