Another Battery switch question.

[Champ 2001]

Getting ready to install a couple battery cutoff switches in my boat. On the cranking side, I have 4 gauge wire to my motor. I'm assuming that I will need the same gauge wire going from the battery to one side of the switch? My trolling side is 6 gauge wire. Thanks!

[Lou r Pitcher]

It may need to be larger.

If 1) the added switch results in increasing the "total" wire run length in delivering current to the outboard and 2) you want total voltage losses to not be increased:

Then the existing 4 gauge would be replaced with a larger gauge and a similar size new wire selected for the switch so as to keep the same 'total circuit' resistance as before.

[Champ 2001]

Its not that much of a run, but yes it will be longer. So are you saying, remove and replace the 4ga positive lead going to the outboard with a 2ga maybe? Then using a 2ga to run to the switch? Thank you for the info!

[Lou r Pitcher]

It depends...... but is impossible to assess not being able to see it.

If the added length is only a few inches (<10% increase to prior switch install wire length) then keeping existing wire likely will be fine and using same gauge for added wiring.

But if adding switch results in adding few feet of new wiring to reach a distant switch position, then a wire table may need to be consulted to ensure the total resistance in the new run does not significantly increase.

[Champ 2001]

Thank you Lou, appreciate the advice!