Very Strange Electrical Hazard/Problem

Charlie Jones s/v Tehani · Jun 20, 2014

Fiberglass is not conductive. You have a short to something metal connected to the engine, probably something touching your outboard bracket. Start by looking at where the bracket is attached to the hull. I'd bet you find a chafed wire somewhere.

Chris Patterson · Jun 20, 2014

No, I can't see the fiberglass being conductive whatsoever. Linemen use 'hot sticks' to reset pole fuses. When this fuse resets, sometimes 12,500 volts are involved, in fact mostly. These hot sticks are constructed entirely out of fiber glass. Rubber gloves are used naturally, as this much voltage will travel through some strange things. However..

(just a thought):neutral:

centerline · Jun 20, 2014

actually, fiberglass, which is primarily plastic resin with glass fibers, CAN be slightly conductive depending on its moisture content, dust or dirt on its surface, and/or any additives that might have been added during mixing.

but also look to see if the outboard bracket is bonded to the battery or wiring from a mounting bolt inside the hull....
what you are experiencing is not unheard of, and not an unreasonable occurrence if there is an AC hot wire short somewhere that is touching the hull..... the boat setting on rubber tires and an AC hot lead touching the hull, and the outboard hanging in a bucket of water... you have created the only path to ground, and your body happens to be a better conductor than the bucket in contact with the ground is... it may not conduct enough to kill a person, but it can conduct enough to tingle.

kill the AC power at the main breaker switch inside the boat and see if the problem still exists... if it still has a problem, the problem is somewhere between the shore power connection and the breaker.

if the problem goes away by shutting off the main breaker, then you must disconnect the individual circuits one leg at a time until you find the one that eliminates the problem.... then chase that leg until you locate the short.

centerline · Jun 20, 2014

Chris Patterson said:
No, I can't see the fiberglass being conductive whatsoever. Linemen use 'hot sticks' to reset pole fuses. When this fuse resets, sometimes 12,500 volts are involved, in fact mostly. These hot sticks are constructed entirely out of fiber glass. Rubber gloves are used naturally, as this much voltage will travel through some strange things. However..

(just a thought):neutral:

the rubber gloves are to eliminate the tingle that can and does happen sometimes...

Chris Patterson · Jun 20, 2014

centerline said:
the rubber gloves are to eliminate the tingle that can and does happen sometimes...

Yeah, I did think of that, and it for sure is primarily for that 12.5 high voltage. A green pole will go hot with this much power, and take ya quickly out of this world. Serious business.

(Sorry fellas, didn't mean to stray the thread, this interests me much).

Where's the path?

kloudie1 · Jun 20, 2014

Reversed polarity ??shore power inlet plug?reversed at AC buss? I dunno

Chief RA · Jun 20, 2014

You must have that outboard in a plastic trash can for you to become a better ground path? If the water is in a metal can just hose down the ground (earth) around the water container. Your outboard isn't grounding thats why you are becoming the ground path.
Does your AC cord have a ground connection and connected through your source to earth ground?
This could be good ol' static charge, especially since most boats do not possess a proper ground system. Plus rubber tires do make a great insulator!
Intriguing little dilemma! Chief

justsomeguy · Jun 20, 2014

Chief RA said:
You must have that outboard in a plastic trash can for you to become a better ground path? If the water is in a metal can just hose down the ground (earth) around the water container. Your outboard isn't grounding thats why you are becoming the ground path.
Does your AC cord have a ground connection and connected through your source to earth ground?
This could be good ol' static charge, especially since most boats do not possess a proper ground system. Plus rubber tires do make a great insulator!
Intriguing little dilemma! Chief

Possibly static charge, but that usually discharges pretty snappy-like, and then has to rebuild.

I had an interesting static event while setting up my boat during a passing front, and was generating 3/4 inch arcs off my outboard's prop to my fingers. It is electrically tied to the battery through the little alternator I stuck on it.

The charges were regenerating fairly quickly, too.

How was the weather, rgranger?

Ken Cross · Jun 20, 2014

Put a meter on it and start chasing it. Use a ground rod driven into earth for the ground side of the meter.

If you don't have one, borrow or buy one. Here is a cheap one:
http://www.harborfreight.com/7-function-multimeter-98025.html

Ken

Allan12210 · Jun 20, 2014

kloudie1 said:
Reversed polarity ??shore power inlet plug?reversed at AC buss? I dunno

Maybe something here, or a short inside the charger? Check for voltage between neutral and ground. I don't think there should be any. Take a wire back to the house ground (a rod driven in or the cold water pipe). Check for voltage from the charger case to that wire.

Ross · Jun 20, 2014

I encountered a problem like this in and around a house with aluminum siding. I was nearly electrocuted. It took me two years to find the problem. The front porch ceiling light had been installed after the house had been sheathed with aluminum siding and the hole cut for connecting the porch light was ragged and contacting a bare hot lead to the light. When the switch for the porch light was "on" the siding for the entire house was energized. The overall resistance is enough to prevent a circuit breaker from tripping but still enough to deliver a "shock".

Allan12210 · Jun 20, 2014

rgranger said:
When I check the voltage across my charger I get 3 V with no load. I have no idea if that is normal.

That may be the voltage across the charger output terminals? I'm thinking you need to check between the charger case and the earth. Does this charger have a third prong on the AC side? I saw your charger in earlier post. I don't know if it has a metal case, or metal heat sink fins, but that's where it might be worth testing to the ground, not between or from one of the two (+ and - output) leads. Is your charger plugged in via an extension cord...maybe one that someone replaced the ends with new male and female connectors?

walt · Jun 21, 2014

If you feel a tingle, its likely some sort of AC leakage.

If its charging from Corona current during a lightning storm, you would get a static shock - it could repeat but it would still be more of a series of single shocks.

Fiberglass in this case should be considered as a good insulator - not involved in your problem.

When you said you disconnected the outboard, did you disconnect both wires to the battery. Are you 100% sure that every possible conductor of any sort was removed between the outboard and your boat DC ground and electrical system?

It sound to me more like an issue with having a small potential on your house green wire (that came from your "shore power" extension cord or some sort of fault in your battery charger. Or your have a mix up in AC wires somewhere in that path (house or boat).

The part that would not make sense from above is that you got the tingle on your outboard when you said it was disconnected. If the outboard was actually 100% disconnected and completely floating - no connection to the ground you were standing on and no connnection to the boats electrical system, then it could be corona current generated by the storms electric field - but corona current would generate a series of shocks, not a tingle.