Proper Boat Grounding

[Bugzilla46310]

Looked through some posts and some of the links in the sticky posts no longer work after a few decades! I think I know the answer but wanted to make sure. The wiring on my 1998 Sylvan 17’ Blue Fish doesn’t look up to my standards and I will most likely clean it up a bit in the spring and if any issues are found I will address those also. From what I see, the ground is never attached to the boat hull, like in a vehicle, but is isolated from the hull and only goes to the battery and related terminals. Is this a correct assumption? Thanks

 

[jlh3rd]

Thats's how it is on my '06 pontoon. I believe the correct term is "floating ground".

 

[Scott Danforth]

that is correct. except for bonding wires, you NEVER pass current thru the boat. it will literally dissolve from galvanic corrosion.

 

[dingbat]

I believe the correct term is "floating ground".

A "floating ground" is an electrical potential not physically connected to the earth/ground.

In the boat scenario, all grounds are tied to the negative post on the battery. The negative battery terminal is then grounded through the motor via the water to produce an earth ground.

Without the earth connection, there is a chance that the boat's potential could be greater than "earth" setting up a possible shock hazard.

 

[jlh3rd]

but the boat is floating...


just kid'n.

 

[jlh3rd]

umm....well, that's not what I'm finding after looking. My pontoon is DC only, but if this "grounding" to earth is through the motor/water/earth, then I can ground my negative any place on my aluminum structure. The motor is grounded to my transom so what difference does it make.
What about an RV.....a car.....
so just asking....

 

[Scott Danforth]

See post #3

 

[airshot]

See post #3

Now even more confused.....my aluminum boat has no wires connected to the aluminum hull, but it does show 12v when testing with a vom. It must be thru the SS bolts bolting the motor on to the transom.

 

[Scott Danforth]

Your hull bonding is to the battery negative

Never use the hull as a ground path

 

[jlh3rd]

I read it and again, and now it's more involved. If dingbat is right then my pontoon is shedding electrons through my aluminum toons.
Not good according to you and I agree.
But is my motor a ground source to the water/earth?....so its not a floating ground?.....

 

[Scott Danforth]

Look up the ABYC standards on electrical and bonding