Hi

I have a 4-layer board with the following setup.

1st layer = components / signals
2nd layer = ground
3rd layer = Power plane consisting of 5V, +12V and -12V
4th layer = signals

Board is basically a controller for a CCTV. 5V is powering a microcontroller, +/-12V is powering op amps which control signals for a camera. No high speed signals on board. Questions are:

1. Is it ok to have the 5V, +12V and -12V signals on one power plane?
2. I have 230V supplying the circuit, I plan to have the 230V traces all on the bottom layer and on one side of the board, I will be using 6mm spacing between traces, vias etc. Standard electrical safety standards for Europe, board is not for resale. Is this ok to be safe and avoid potential arcing?
3. I presently have 9 mil (default on software) as the thickness of each substrate between the 4 layers, is that thick enough to avoid 230V issues?

 

Why do you need a four-layer board?

 

I've found the answer. This can be closed.

 

I'm new to PCBs greater than 2 layers as well as 230V incorporated onto a PCB so pleased bear with any ignorance: Board is basically a controller for a CCTV. 5V is powering a microcontroller, +/-12V is powering op amps which control signals for a camera. No high speed signals on board. Questions are: Is it ok to have the 5V, +12V and -12V signals on one power plane?
HPInstantInk