Isolator switch

[Syncrobaz]

Hi guys, I'm fitting a new starter motor to my mv Syncro so I thought I'd up the main cable to 25mm 170 amp.

I'm fitting a main isolator switch under the driver's seat in case of an electrical fire.

It would be easier to fit in the earth cable line instead of positive, would this cause any problems ?

Thanks Baz.

[CovKid]

Nope.

[garyd]

Baz,
just thinking. Wouldn't an electrical problem (fire?) mostly likely be caused by a live feed being damaged and shorted to earth?

In this situation, with the engine running (and the alternator charging) would a battery earth cut-out actually kill the power to the live lead? If correctly located it would take the battery out of the picture but, with the engine earthed to the bodyshell, the alternator output would still keep the wiring live.

If the alternator is connected solely to the battery +ve terminal and the cut out is between this and all the power feeds, then the cutout would kill both battery & alternator supplies. I think this is correct but quite happy to have someone correct me.

I appreciate that with the MV engine (and the battery presumably under the seat) it would be difficult to achieve this with a single cutout but there may be a way. Does everything at the back feed from the starter supply cable? Is the dash/fuse box fed from the back or direct from the battery?

[Syncrobaz]

Hi Gary
Yes,battery at front with 2 extra feeds (cab )? red. red/white which wont reach the cut
out switch.. Also feed from starter to alternator.
To be on the safe side I'll fit a junction box to connect cab wires to the main feed from the switch.
I guess that will solve the alternator problem as it won't charge without a power supply ?