[rotorwrench]

A battery disconnect isn't like an inter-circuit on-off switch. If no systems will energize when a battery is reconnected then there will be little or no arcing at all. This is basically a battery switch. Now if several loads are connected live in the car's electrical system then it will draw a load when the battery is turned on and can arc at the switch contacts.

Most battery switches are designed to give a rapid hard contact close when switched ON which will minimize arcing but it may still have a little if there are any loads ON in the car's load circuits.