Battery cut off switch

[davidball]

I have bought a battery cut off switch
http://img149.imageshack.us/img149/8986/masterswit...
which has a cable, with a 30amp fuse, that bridges the two large terminals. What is the purpose of this cable?

[BertBert]

Are you sure it bridges the terminals? Are you sure it's a fuse? I thought the master switch had to dump current to earth through a resistance to stop the alternator going pop when the switch is used with the engine running.

Bert

[Mkindy]

I think Bert is right, the link below with instructions and diagram could be helpful it worked for me.
Andrew
http://7faq.com/owbase/ow.asp?HowDoI%2FFitA%5FBatt...

Edited by Mkindy on Wednesday 21st January 15:30

[davidball]

There are only two terminals on the switch, one to connect to battery + the other to go to the battery side of the starter solenoid.

[Red Seven]

David,
It looks like you've bought a "battery isolator", not a "master switch".
If you were to switch this switch to the "off" position whilst the engine was running, it would not stop the engine! (unless you are running a race car without an alternator)If you are running a conventional setup with an alternator, then there is a risk that the alternator(and the rest of the cars electrics!) may be damaged when the switch is switched off when the engine is running!
A master switch has three switches. A main, normally open switch that switches the battery power, a second normally open switch that is connected in the ignition circuit so that the engine stops when the master switch is operated, and a normally closed switch that is used to ground a resistor to the chassis from the alternator output to disipate any residual current from the alternator.

Edited by Red Seven on Wednesday 21st January 18:30

Edited by Red Seven on Wednesday 21st January 18:31

[davidball]

Hi Red Seven. Thanks for the explanation. It seems I have bought a cut-off switch and not a master switch, though Richbrook describe it as a master switch. I emailed them asking for fitting instructions but have not received a reply todate. Anyway I have now bought a switch that has the correct connections.