Unique Electrical Problem

[Private Nemo]

Hi, I have a 1985 Formula 28pc. I have unique problem I think. The boat is still out of the water until I straigten out the last few problems.
With dock side power connected to the boat , I get 50v , sometimes 110v, from the outdrives to ground {earth}. As you can imagine thats a heck of a shock.

Has anybody seen this or have any idea what could be causing this ?

thanks

Drew

 

[Bob's Garage]

Re: Unique Electrical Problem

I have absolutely no experience with a boat's ac power source/system. But maybe I can get the ball rolling.

I am going to make some assumptions and propose a course of action to locate a possible short.

Assumption 1: The boat by your description is on the "hard".
Assumption 2: There is a faulty circuit leaking current to the dc grounding system.
Assumption 3: That there is a circuit breaker panel that isolates each ac and dc circuit.
Assumption 4: That everything not permanently installed into the ac system is disconnected.
Assumption 5: That the ac circuit is not supposed to use the boat's grounding circuit as a return.

Action 1: Turn off all ac circuit breakers. Test for leakage to ground as performed before.

Result: If "0" then problem is in one of the circuits.

Result: If problem persists then source of problem is between the ac inlet and the breaker board.

Action 2: If "0" then energize each circuit breaker individually until problem reappears then visually inspect that circuit and test any equipment on the line. Could be the A/C, refrigerator, built in chargers, lights, plug in accessories or an outlet. Check for cross contamination between ac system and dc circuit.

Action 3: If problem persists, visually inspect and test wiring and inlet for a short to boat ground. Look for frayed wiring, burned contact at the inlet and anything else that is not supposed to be there.

As I said, I have no experience with the ac systems on a boat but this is how I would start looking for the problem. Then as I was testing I would be learning how the system was designed to work and would go from there.

Someone with the knowledge of the system will probably be able to chime and be of greater help.

 

[Bob's Garage]

Re: Unique Electrical Problem

Hi, I have a 1985 Formula 28pc. I have unique problem I think. The boat is still out of the water until I straigten out the last few problems.
With dock side power connected to the boat , I get 50v , sometimes 110v, from the outdrives to ground {earth}. As you can imagine thats a heck of a shock.

Has anybody seen this or have any idea what could be causing this ?

thanks

Drew

By the way, this is really not so unique. When I was in Nam during the conflict I worked out of a shop truck that ran off of a generator. We could measure 110 volts from the step to the puddles around the truck. We had to make sure we did not stand on the step at the same time as we stood on the ground or we got "lit up". Between the Sargents and Peons there was probably 100 years accumulated knowledge and we never got it fixed.

It started on it's own and didn't stop until we went into a permanent building. Not as dangerous as your problem however due to the shock hazard to anyone in the water with your boat.

 

[markheck1]

Re: Unique Electrical Problem

I know, dumb question but I still gotta ask, you are using the right grounded cord, and not something into one of those 3 to 2 prong adapters, or the ground pole cut off to go into a 2 prong outlet, and you are sure the outlet is fine?

 

[dingbat]

Re: Unique Electrical Problem

Sounds like the mice have been chewing on your electrical system.

 

[Private Nemo]

Re: Unique Electrical Problem

Hi, Sorry I havent got back to thread; life. Thank you for the replys. Markheck1 got me thinking about ground and sure enough the electical strip I was plug into was missing the grd pin. Thats OK.
Because when I plug into a standard house plug , I pop the circuit breaker on the boat. I do not want to bore everyone with my search for the short , but what I found made no sense. Behind the circuit breaker panel I found someone had connect a white [supply]wire to green [grd] wire. I Took the white wire off and everything seems to be fine.

thank you for the responsees , they pointed me in the right direction.

Drew

 

[Bob's Garage]

Re: Unique Electrical Problem

Hi, Sorry I havent got back to thread, life. Thank you for the replys. Markheck1 got me thinking about ground and sure enough the electical strip i was plug into was missing the grd pin. Thanks OK.
Because when I plug into a standard plug , I pop the circuit breaker on boat. I do not want to bor e everyone with my search fot he short , but what i found makes no sense. Behind the circuit breaker panel i found someone had connect a white wire to green wire. Took the white wire off and everything seems to be fine.

thank you for the responsees , they pointed me in the right direction.

Drew

The green wire was probably the "earth ground" that was connecting various metal parts of the boat to the grounding plate, or outdrive, for discharging static electricity to avoid a spark at the wrong time/place. If the white wire was in the ac circuit it was sending the current directly to the water, as you discovered.

 

[glenn property of pam]

Re: Unique Electrical Problem

hmmmmm 50 volts sometimes 110v indicates a floating voltage. (55 volts on the netrual and 55v on the live but together there 110volts which means at no point is the netrual connected to the ground thus the broken ground pin) i do not know the code requirements for a boat and i have not got the code book at home to check but im thinking if you are connecting to shore power 110v and the white wire has power that sounds like you have the plug wired backwards (110v white to silver black to gold green to ground). buy a cheap receptical tester it will tell you if its correct inside the boat. if your main breaker is a gfci then get the receptical tester that also includes the gfci test button and test the circuit. im concerned that if you have a generator you may have removed the grounding point for it (old style generator) things were done diffrent in 1985 then they are today and the rules on grounding a netrual are diffrent but it seems odd that it wasnt shorted it was jumpered and now it doesnt work (test the dock side plug as well maybe thats wired backwards or the wrong voltage)