How is industrial wiring being done , give any of the process?

For Power  :-

1- Study the type of load ( 3ph or 1 ph), voltage supply , the tempereature ( Air , soil , ground ) , the type and the desired  installation type  ( Tray , conduit , trench...) .

2- measure the distance between the source and the machine or desired device .

3- using calculation formulas tables or computer-assisted program to find permitted voltage drop and cable size .

4- compare the characteristics of the of the calculated table with the desired .

5- consider the country regulation  , safety  and international codes wiring , insulation and termination .

For control wiring :-

1-      Study the available space inside the electrical machine box ..

2-      Read the characteristics  of the device itself..

3-      Use the recommended cables suggest by the vendor , if not find the rang of amp and choose the corresponding size for it .

It can be don through condiuting, and undergroun wiring