Grounding the hull question

[ARCWINSTON]

I am replacing the nasty crimps upon crimps upon crimps that join the ground wires from all the ancilliaries in the back end of the boat with a ground buss bar. My thought is to insulate the new ground buss bar from the aluminum hull but I read recently that aluminum hulled boats should have a ground wire from the battery neg. to the hull. Is this true or urban myth. To the best of my knowledge, all the electrical system components have insulated return grounds and nothing goes through the hull. Comments please...W

 

[rickdb1boat]

Re: Grounding the hull question

No grounds to the hull.........

 

[DangerDan]

Re: Grounding the hull question

There is only one point where the DC side is grounded, and that is at the battery. It, too, is a "free floating" system in which nothing is ever grounded to any metallic part of the vessel, most especially not the bonding system. Just like a car sitting on rubber tires, completely insulated from earth potential, the battery itself provides the negative potential.<br /><br />Read more on Grounding & Bonding<br /><br /> http://powerboat.about.com/gi/dynam.../marinesurvey.com/yacht/ElectricalSystems.htm

 

[ARCWINSTON]

Re: Grounding the hull question

Thank you sirs, that is what I thought.<br />DD that's some interesting info, again thanks.<br /><br />So, does all that mean that the motor, which is obviously grounded to the battery, should be insulated from the hull? Which it isn't. Also, if the underwater metal components should be bonded together,then the hull should be bonded to the motor which in turn is connected to the battery ground thus creating a connection that shouldn't be there!!! I read and re-read the grounding / bonding info but couldn't draw a conclusion from it regarding this hull/motor/battery confusion in my mind. Would you guys care to enlighten me? Thanks...W

 

[Dunaruna]

Re: Grounding the hull question

That article is refering to larger vessels that have active bonding systems and hard wired shore (AC) power. The main concern in that article is 'active' shore grounds getting tied up with active DC grounds.<br /><br />'Grounding' and 'Bonding' serve two completely different purposes, but the end result is visually similar. <br /><br />Your motor is both grounded and bonded - grounded through the negative battery cable, bonded through the clamps and bolts (and sometimes small SS cables). <br /><br />You should never use the hull for ground connections, but bonding is sometimes required depending on galvanic activity.<br /><br />Your observations are correct, through the motor, the hull is grounded, but as long as ALL your accesories have good individual grounds back to the battery and do not use the hull for ground, your good to go.<br /><br />Bob

 

[ARCWINSTON]

Re: Grounding the hull question

Thanks for that clarification Bob. I do believe I am "good to go"...W