there is no main shutoff... no master switch... the closest thing to it is pulling the aquabus that powers the main unit.. (which you wont have to do since yours is connected to the EB4..)
just pull the aquabus out of the '8, pull the power plug, relocate the '8, wait 30 seconds or so and then insert the aquabus...
... the system is plug and play.. so you shouldn't have to restart the base module for it to recognize the '8.. your programming for each outlet will remain intact..
after you get everything set back up, you may want to restart the base module, but i wouldnt think you should HAVE to..