MCB symbol

Arrows indicate the direction of switching ( make & break) and it indicates that the switching will be done manually / by hand.

Do you have any books?

Your constant questions indicate not!

Where is this symbol from?

In some obscure document, the arrow was given to indicate that the product is a trippable one, in the event of an abnormal condition like overload or short circuit.

i have not seen it in wide use though.

This is the usual symbol used (remember that single-line schematic diagrams are normal, represent 3Φ systems)

(coolyaar, don't get me wrong, you are already a qualified engineer possibly earning a salary, and you have just started learning electrical symbols. i refer to your other post on symbols. You have a looooooong way to go before getting into the nitty gritty of electrical engineering. Rather difficult to do it via CR4 i think, though all of us here will do our best to help you. Good luck!)