I have created a system using arduino where it controls 5 different electric lines. For example: Line 1, Line 2, Line 3, Line 4 and Line 5. What arduino does is, it turns on the Line 1 if it has power and if it doesn't have power it turns on the Line 2 and etc. Arduino turns on/off the 5V relay and it has at least 5 sec interval when switching from one line to another(in this case I have 5 x 5V relays). It is working perfect and I am very happy with the system, however I am concerned about relay fails to disconnect when commanded.
For example: If Line 2 was on and suddenly Line 1 also gets power and arduino will turn off Line 2 and after 5 secs it turns on Line 1. What if Line 2 relay didn't brake the curcuit? I think I will have a fire or something really bad.
My question is, can I some how make fuse so that never more than one lines will be connected?
See my schema: The reason I am doing this is, in our office we have 5 different lines of electric and I want to control it automatically. Also I would like to see which line has power and being able to control it from the computer.