I've the following circuit , that used to measure the current through shunt resistance ,

The circuit have analog & digital ground , the terminals 1 ,2 ,3 are for AC source .

I need to protect this circuit from shorts .

So where's the right place to put the fuse ? & how to know that this is the right place ?

Will be a fuse on the digital side and the analog side ?

any other recommendation for this circuit ? I found out that 7805 voltage regulator is getting hot fast .

Edit #1 :-

R3 is shunt resistor with 200 u ohm resistance