Grounding a wood boat

I need some help. How to ground all AC and DC systems when you have a
OUTBOARD engine. 2 house batteries 1 starter battery.
Do I ground all systems to the starter battery negitive?

 

The out biard engine is your ground, through the connection to the battery negative. So yes, the AC grounding (green wire would be connected to the batterynegative ground.

 

Thank you Ike. I have owned inboards but not an outboard boat. So if I run all ground leads for DC to a negative bus bar and all leads AC to a seperate ground bus bar then connect those 2 negitive wires to the starter battery negative, I'm good to go.

 

Basically everything is the same as in your inboards, where the engine block is the ground point.

 

Yes, it the engine is the common ground. Electrically it is the same to ground everything at the negative in the battery or a negative buss bar.

 

I see how you are terminating a circuit and calling it a ground but I'm not understanding how you have an electrical ground with outboards when the engine(s) are up. What about a grounding strap?

 

I have no experience with AC on a boat. When you talk about grounding the AC circut, do you mean the third, protective ground wire as used in US domestic AC wiring, or the nominally "neutral" wire?

 

Yes, I will run marine 3 wire AC to lights, couple of plugs and air conditioner with the ground wires to a negitive bus bar then a cable from the bus bar back to the starting battery negitive post.

Thank you all.

 

Y

Yes, the third wire. Unfortunately the terminology can be confusing. The third wire is the "grounding" wire. That is the green wire.

The white or "neutral" wire is the "grounded" wire. But it is not grounded on the boat. It is grounded back at the source of power, which in the case of a boat without an isolation or polarization transformer, is back at the power station. If you have a transformer it is "grounded" at the transformer.

 

For AC best to review regulations...Particularly Ground Fault Interrupters on the wall outlet circuit.

AC is dangerous when the boat is out of the water and you no longer have a seawater earth. The green earth cable must contact a shore earth.

 

Absolutely. Never power tools off your boat's AC when on the hard. There is no longer a ground path. Run an extension cord from the marina's out let to keep the ground path.

But best to review standards for AC. See http://www.kroescorp.com/Other/e-11.pdf
It's an older version but still better than none. Or ISO 13297 if that's your flavor http://newboatbuilders.com/docs/N863_CD_13297_Small_craft___Electrical_systems.pdf

 

using a GFCI means the extra ground wire is no longer needed.

http://www.diychatroom.com/f18/can-gfi-work-no-ground-wire-43549/

So consider always using one. I have an extension cord with a GFCI built into the plug. I use this on the boat for power tools. One end is GFCI, other end has 4 plug sockets.
You can still be killed with a GFCI. take a hot wire and a neutral and become the circuit with wires in each hand. If no current can flow outside of you being the only path, then the GFCI will not trip and you will be electrocuted. GFCI is testing for stray currents where current imbalance occurs. Current going out not equal to current returning, so it trips off.

 

There are basically two types of electrical trips, one is called ELCB (Electronic Earth Leakage Breaker) annd the other one is an RCD (Residual Current Device)...they both shut off the power (circuit breakers) when there is a fault, but do it in two different ways.
The ELCB trips when there is a fault to earth, the RCD trips when there is an unequal load between the live wire and the neutral wire, an imbalance in the circuit.

In Australia now we use the RCD instead of ELCB type interruptors.

 

grounding a boat tank-help?

Hey everyone. As I can see D/C is Different From A/C. Just so I get it straight. If I am grounding a boat tank I should run the fill ground all the way back to the tank. The Neutral/Ground from the sending unit goes to the Neutral/Grounding bar under the steering wheel where all the fuses are. Should I run another ground to the battery from the tank. Trying to avoid electrolysis. Another thing, I thought the fuel tank area was suppose to be sealed off/water tight. Should I plug this opening? If I don't will this speed up electrolysis. Heard different things from different boaters. I just want to make sure it is right the first time. Mistakes on a boat are costly. Can anyone help?

 

http://forums.iboats.com/showthread.php?t=62969
etc...

http://forums.iboats.com/showthread.php?t=446457
some boat tanks are just bonded to underwater metal but better to ground it to negative terminal.