u can off it actually but u will then have to manually on it again every time the RH goes above some level (i guess 50%?) if u dun find this troublesome.
the machanism inside is supposed to switch itself off once the RH inside the cabi goes below the pre-set value thus saving ele. I guess if the auto-shut off function is not working then u resort to manual switching.
Oh for goodness sake... !
A dry cabinet is not a Ceiling Light or a TV Set; just leave it on 24/7. It only consumes a couple of watts.
Turn it off and the humidity will build up, and LPPL, you get fungus despite having a dry cab...