Originally Posted by BFlinn181
Perhaps the difference in recommendations is that the Perko switch is an enclosed switch while the ones in the video are all pretty open and uninsulated.
I believe that is exactly the reason for the difference. With the switches that go on the batteries, all that exposed metal could be a safety concern if it were on the positive terminal.
With an enclosed and insulated switch, like the Perko, I think it would be a bit better to have it on the positive side. My rig came from the factory with house and chassis battery cutoff switches, and both are on the positive side.
Special note: before installing a cutoff switch, or doing any work on any of the high current battery leads, ALWAYS disconnect the negative terminal first, and reconnect it last. Make sure the negative lead can't accidentally contact the negative battery post: tape it in a safe position if you must. If you leave the negative lead connected while you have a wrench on the positive lead, that wrench could turn into a dangerous short circuit if it touches anything metal near the battery!
Note to those with the factory switches: not all loads are necessarily cut off when you open those switches. On mine, when the house switch is open, power is still sent to the slideout controller board, and to the optional solar battery controller. When the chassis switch is open, power is still sent to the starter motor plus two circuits to the engine. So, if you're going to replace the starter, for example, don't just open the cutoff switch and begin wrenching on the starter's cable connector - you still should remove the battery negative cable first!