However, it occurs to me that I could reduce the wiring length & complexity of joining all the cables together (where the black and red meet in the middle) by 'daisy chaining' the Positive wire (Red) along the relays and daisy chaining the Negative wire (Black) along the Solenoids.
I have considered doing this since the solenoids will be strung out over a number of meters and I may need to move to an 8-relay set up which means double the number of wires to join together.
I have tried to show this daisy chaining in Picture 2. I don't think this is a 'Serial' circuit since the current can flow between any Solenoid without going through the Solenoid (at each point, 2 wires are touching each other and the Solenoid).
My question - will the second approach work and is it safe or should I stick with approach 1?
FYI, this is the Lock with the Solenoid that I will be using... 12V Electromagnetic Cabinet Lock as it seems to handle much more load on the latch than a 'cheap' pull solenoid would due to the Spring-loaded latch and the lever which releases it. It is also cheaper than most regular solenoid powered locks. I think it is the one used in Amazon lockers :)