25 Cruiser chassis ground location?

[Tomkuehn]

I’m installing a Pronautic battery charger. I’m using the common bus bar (located next to the starter battery) for the negative DC connection to the charger..I also need to bond the charger to the ‘chassis’ ground. Where is that located? Thanks for your help.
Tom Kuehn

 

[T.R. Bauer]

I’m installing a Pronautic battery charger. I’m using the common bus bar (located next to the starter battery) for the negative DC connection to the charger..I also need to bond the charger to the ‘chassis’ ground. Where is that located? Thanks for your help.
Tom Kuehn

All of my grounds go the battery (one way or another) as there really isn't a chassis ground on fiberglass boat like there is boats that conduct electricity. Some folks will say that "stuff" also needs to be grounded to seawater, which is probably true, but I think that happens no matter what on most boats since the negative on the battery is tied into the negative on the outboard which is sitting in salt water, or least the bottom part of the bracket is. I'm no expert and I can't wait to hear what some of the others say.

 

[journey on]

Here's my 2 cents worth.

Chassis ground is different from signal return or power return. I found out the hard way that modern marinas separate the 110 Vac power and chassis also, so if you have a power return/ground tied to a chassis return (as I did, unknowing) the dock circuit breaker will blow. Took me weeks of searching to find the inverter AC power and chassis were tied together internally. Had to lift the chassis ground on the inverter. Factory had no explanation for why it was designed that way.

So what does the chassis ground do? It ties the chassis to ground in case of a fault on the power side as does the green wire in your house. It also grounds stray signals so you don't have them interfere with the units operation, such as the plotter or the depth sounder. I have separate grounds for the 110 Vac and the 12 Vdc.

On the 25 I have a 12 Vdc chassis ground running to the bronze through hull in the back of the cabin. The AC has its own ground provided by the normal 3 wire 110 Vac wiring. If you're charging a battery by using a 110 Vac generator you can run a separate wire from the generators chassis to the through hull, but you don't need to.

Boris

 

[thataway]

Tom, Congratulations on choosing a great charger.

Bonding Stud A.K.A Chassis Ground - This stud is connected to the boats bonding system as well as the bus bar or terminal stud mentioned above. This conductor is permitted to be one size smaller than the DC positive conductor chosen above; in the case of a DC to the case fault, this conductor is critical in carrying the fault current to trip the fuse or breaker, the AC ground CAN NOT handle high DC amperages.

Typically the "bonding system" is the ground wire which runs between thru hulls and hull zincs. If we don't have a thru hull in our C Dory, your choice is probably the outboard bracket....which is connected the "ground" or negative wiring. But, I would take the chassis ground to the outboard....Bolt if accessible. If not, the ground nearest the engine. The quote from the manual seems to imply that the negative bus bar nearest the battery is OK.