What to use for a ground block

[imonna 19 6]

Good Evening,

Simple question I hope.  What do people use for a ground block as an intermediate to the negative on the battery.
the boat i have is set up with a big bolt that is mounted under the dash.  The bottom of this bolt  is connected to the battery and all the electronics on the boat are grounded to to the top of the bolt.  

It seems to work fine, but seems kind of 'Homemade".  Before I alter it I wanted to find out what people suggest.

thanks
Bill

[Circle Hooked]

I use the bottom one

one

[seabob4]

...as do I.  Forward...


And aft...

[GoneFission]

Looks nice Bob!  

[seabob4]

John,
The bottom pic is from the Pathfinder 2200V I have at the house now.  How's this for a console?


She looks like this now...


This is going to be a "fun" boat, plus she's dual station...

[seagate]

Ha seabob how much would you charge to do a 1985 200XF I want mine to look like your boat.

[imonna 19 6]

those are some nice looking set-ups.  I will be moving in that direction, but mine still looks like a well organized Rats nest.

So I have a starting battery and a house battery.  The ground block is for the house battery.    

What amp rating do i need when purchasing a  bus bar.

I don't really understand electricity all that well and its scares the heck out of me.

Thanks
Bill

[seabob4]

Ha seabob how much would you charge to do a 1985 200XF I want mine to look like your boat.

$1K + materials.  You drop off and pick up...

Materials are typically in the $750 range, all new wires (except for engine harnessing), switches, breakers, I re-wire you switch panel, you may want to check out my thread on THT...http://www.thehulltruth.com/boat-commer ... lando.html

[seagate]

I'll have to start putting some money away so wife doesn't freak out but that sound good.

[imonna 19 6]

I bought a 150 amp common bus bar to use as the ground block, which will collect all the negatives and run them back to the battery.   This may be a really stoopid question, but does the amp rating for the bus bar matter when using it for a ground block.

Also, running two twelve volt marine starting batteries, what amp bus bar would i need for my hot wiring, if I where ever to change them.


thanks
Bill

[Capt. Bob]

I bought a 150 amp common bus bar to use as the ground block, which will collect all the negatives and run them back to the battery.   This may be a really stoopid question, but does the amp rating for the bus bar matter when using it for a ground block.

Not stupid but....
Think for a moment. The current passing through the ground bus bar is (for the most part) equal to the current passing through your "hot" bus bar. Sounds like good practice to have both rated the same.

Also, running two twelve volt marine starting batteries, what amp bus bar would i need for my hot wiring, if I where ever to change them.

To really size the bar(s) you need to know how much "juice" (aka watts) you will be consuming. For those users that rely on just a few accessories and don't live on their boat (like me), a 150 amp rated bus works fine. It would mathematically allow for 1800 watts +/- so .... unless you're an electron junkie

Calculating that load isn't as critical as doing it to size your battery(s). Do it once and you have it for both uses.
Me, I just roll the dice and carry a big paddle. 8)

[seabob4]

If you think about, the only 2 times any electrical system is going to see greater than 150A is during starting of the engine, or a direct short of the batt cables, hot to ground.

Now with the engine start circuit, the ground cable from the engine goes straight to the batt, and the hot goes either to the batt, or the batt switch, where typical batt switches are rated at 350A continuous, upwards to 500 to 750 momentary.  So no problems there.  Remember also, engine electricals and house electricals are 2 completely separate entities save for a common ground.  The best way to protect the house electricals is to pull power either straight from the batt or from the "common" on a batt switch, then run it to a 40A breaker, as shown here on the Pathfinder...



Any over-current issue will be stopped dead in it's tracks by the 40A breaker.  Another thing to look at is just how many devices running at the same time would it take to add up to 150A?  A HELL of a lot more than are installed in the average boat.  But keep this in mind, a boat's electrical system, although 12VDC, is just like a houses.  You may have 100A service into your home, but add all the appliances up and it will excede 100A, which tells you you can't run everything at once.  Now when I wired boats at Stamas, I installed a second 30A shorepower inlet if the boat got AC.  Now typical marine AC units run at around 6A, but the kick-in amperage of the compressor can be around 22-23A.  Run the microwave and a single burner stove and a single 30A would be tripping constantly...

[imonna 19 6]

Thats a lot of info to absorb.   A follow-up question regarding grounding my fuel fill to my tank.

I am running my 10 AWG ground wire from a  terminal clip secured to a stainless steel bolt on my stainless steel deck fill.  

My aluminum tank has a 1 inch bracket with a hole as a ground tab.  

I assume i am supposed to put a bolt through the tab hole and run my ground wire to my negative bus.

The question is what kind of bolt do i use.  Reading all this about dissimilar metals has got me unsure about using a SS bolt.

Or is their a better way to make that connection.

Thanks
Bill

[seabob4]

Bill,
That's the way it is done.  I doubt you are going to find aluminum machine screws out there (machine screws are baby bolts, they don't call them bolts until they hit the 1/4" size).

I've rewired a ton of boats of all makes, have never really seen an issue with a galvanic "occurance" due to dissimalar metals at the tank...JMHO.