Solar Panels shut off

[Jumbuck]

What's the best type of shut off/switch and safest to disconnect a 300 watt parallel solar array (3 x 100) from a charge controller?
I was using an Isolation switch but noticed corrosion on the positive side. The switch is indoors and low humidity.

The wire from the panels is a 10 mm2 tinned dual cable and on the other side of the switch a lesser gauge plain copper.
I intend to connect another 300 watts in a 3S2P configuration.



Screenshot 2022-12-27 2.28.38 PM.pngScreenshot 2022-12-27 2.29.07 PM.png

[Calsun]

Best to check the local fire codes for your location. Ideally the shut-off should be where it can be accessed from outside the building and reached without need for a ladder.