Originally Posted by samnelso
A lot of the racers cut the switches off their speedos to free up valuable real estate. In doing so, there will be a small arc when connecting the battery. The arcing is of no concern.
I dont know the OP's ESC personally, but yes, some people cut the on off switch off and you might see a small pair of wires just outside of the esc joined together if you got the ESC used
, this would usually be where the previous owner has bypassed the switch.
Just a guess though, hope it helps somewhat