Forums, Electrical Systems, Navigation and Safety equipment, Battery Master Switch

Mons Meg at 02/03/2020 19:03:49
A quick question for the electrical boffins.

My boat, built in 1979 for a very exacting engineer, has the battery master wired in on the negative side of the circuit. I’m about to fit a shore power battery charger capable of charging two batteries simultaneously but, if I connect the charger’s common negative terminal to both batteries, this will bypass the master switch’s ability to isolate one battery from another. After conducting a little research it appears that the norm is for the master switch to be on the positive side of the circuit and that I ought to rewire accordingly. Before I do, does anyone know why my boat may have been wired this way?

George Isted at 11/08/2020 14:04:50
yes it is normal to be switched on the positive side, I think yours must have been modified at some point along the way.

Some boats have an additional switch to isolate the negative but that is less common and I hev not come across it on a Co32 before. Some french boats seem to have it.