Electricity,
The way I see it:
DC:
Each battery bank is a circuit, from the "+" to The "-" .
Anything connected to this circuit is protected by a fuse or CB in case the device goes bad, and electrons go from + to - to fast, making wires too hot.
If you have more than one bank, and want to be able to power everything with either bank you connect the "-" to a common place (negative Bus). As long as "+"s are separated, you have separated circuits. You choose which battery (bank) powers up by way of a Battery switch.
If you have an Alternator on you engine, then, to charge your batteries, you connect you negative bus to the Alternator negative ( at engine block) and the alternator positive to the positive on the battery banks.
To keep the circuits separated you use a Battery Isolator or some similar device.
Same case with Battery chargers......
AC:
They have their own Positive (Hot) and Negative (neutral) (since they are Alternating, they switch back and forth), but in case something goes wrong in AC devices, AC electricity have a "Ground" (green) wire so AC electricity goes back to it's own place!!!, and does not cause damage to you!!!!
Lightning....
Its a circuit between the sky and the ground ( or water), and Only shows Up by invitation...... ( static + electricity charge, or lightning sees water and your boat is on the way). Some boats have installed lightning diffusers, ( lighning invitation busters).
If lightning shows up, you want all your electric circuits in your boat invisible ( independent) to lightning, so you Hide them, by making an easy Path that allows lightning to go to The better ground ( water) (Mast, wire, keel, water ) without going thru any of your electric or electronic equipment, but, just in case some Lightning electricity goes to your Boat hull or equipment, you connect all your Negative grounds to the water By way of the propeller and shaft, or a plate, or the Keel.
The sky and the water are a circuit, and the negative grounds might be together but if there is no positive connection they are like any other circuit in your boat...independent of each other.
Ok, Tell me what else do I need to know.
The way I see it:
DC:
Each battery bank is a circuit, from the "+" to The "-" .
Anything connected to this circuit is protected by a fuse or CB in case the device goes bad, and electrons go from + to - to fast, making wires too hot.
If you have more than one bank, and want to be able to power everything with either bank you connect the "-" to a common place (negative Bus). As long as "+"s are separated, you have separated circuits. You choose which battery (bank) powers up by way of a Battery switch.
If you have an Alternator on you engine, then, to charge your batteries, you connect you negative bus to the Alternator negative ( at engine block) and the alternator positive to the positive on the battery banks.
To keep the circuits separated you use a Battery Isolator or some similar device.
Same case with Battery chargers......
AC:
They have their own Positive (Hot) and Negative (neutral) (since they are Alternating, they switch back and forth), but in case something goes wrong in AC devices, AC electricity have a "Ground" (green) wire so AC electricity goes back to it's own place!!!, and does not cause damage to you!!!!
Lightning....
Its a circuit between the sky and the ground ( or water), and Only shows Up by invitation...... ( static + electricity charge, or lightning sees water and your boat is on the way). Some boats have installed lightning diffusers, ( lighning invitation busters).
If lightning shows up, you want all your electric circuits in your boat invisible ( independent) to lightning, so you Hide them, by making an easy Path that allows lightning to go to The better ground ( water) (Mast, wire, keel, water ) without going thru any of your electric or electronic equipment, but, just in case some Lightning electricity goes to your Boat hull or equipment, you connect all your Negative grounds to the water By way of the propeller and shaft, or a plate, or the Keel.
The sky and the water are a circuit, and the negative grounds might be together but if there is no positive connection they are like any other circuit in your boat...independent of each other.
Ok, Tell me what else do I need to know.