Electrical-Motor Control Circuit

Although a switch anywhere in the circuit will break it in principle, it is custom for the load, in this case the contactor coil, to be attached one side to the neutral rail, then all the switches go between the other side of the load and the live rail. This is so that someone working on the equipment with the panel live won't get a 'handful of voltrons' when touching something around the load with the load switched off. So follow the established custom.

What are you trying to protect?

The contactor?

The motor?

The wiring?

You first must clarify if you are referring to the Auxiliary Contact of the OL relay being ahead of or behind the contactor coil circuit, as has already been surmised, or if you are referring to the SENSING component, the "heaters" of the OL relay being electrically ahead of the contactor main contacts or behind it?

If you are referring to the SENSING elements, it doe not matter, it's just convention to put it down stream of the main contacts. Generally, the manufacturers make the OL relays so that they attach directly to the load side of the contactor, so that makes it easy to do. But if you want to go to the trouble, nothing is stopping you from putting it anywhere you like.

If you are referring to the aux. contact location, there is convention involved in that too, but again, it makes no legal difference. there are however several technical considerations.

the current will be the same whether the overload is before or after. It usually appears after because thats how manufacturers make them - a contactor with an add on thermal overload relay - they butt up to one another

No difference!. We connect relay after the contcator more out of conventional rather than any technical reasoning.

It would be upside down and backwards.