Batteries electrical wiring

[rico]

In my Jeanneau Sun Legend 41 there are two battery banks : one to start the
engine and the other for services.
On each positive lead there is a big switch.
The negative leads of the two banks are connected together and go to the
boat earth but through another major switch.
Although I found out this arrangement is quite common on french boats, I do
not understand the advantages of the switch on the negative lead.
Anyone can help me to understand ?
Thank you.

 

[VMALLOWS]

The thought process seems to be along the lines of galvanic corossion, though I can't really think of a meaningfull explanation on a plastic yacht. It makes more sense on an aluminium hull. It certainly won't do any harm.

 

[pvb]

One possible reason...

One possible reason would be to enable you to completely isolate the batteries when the boat is left with a shore-power charger connected. Potential grounding faults with shore-power circuits can lead to enhanced electrolytic corrosion when boats are connected to shore-power, so being able to isolate the batteries from the engine might help prevent corrosion.

You could always ask Jeanneau (www.jeanneau.com)!