What is LARGE?
Use the same connector as you are using for your battery.
Cant find it now but but Hobbyking have had special adapters made of battery connectors for this purpose.
You normally wont find any high amp connectors in the hardware shop suitable for model aircraft.
I have thougt of a car fuse with holder but they dont come in high amps (30A)
I asked HK if they had an application for this and they said:
Hi DICK ,
Thanks for contacting the HobbyKing Support Team.
Unfortunately we don't carry such switches because they really weight a lot, and are not reliable enough. That is why all batteries get unplugged instead of switched off.
However there are quite a few ESC's with switches built in the electronic circuit, so you actually can switch the ESC off with real soft switch.
Sorry that I couldn't provide you a ready solution.
Have a great day!
Thanks for emailing support.
If you have any other questions, please let me know.
HobbyKing Support Team