This is a pcb layout where I am converting 220V rms to a DC voltage (for microcontroller). The pcb has severe size constraints. This is one design I could come up with:
Circuit explanation: Consider the encircled portion. Top pad is not connected. Second one will receive a 220V signal (sometimes). This pin is connected to 270K resistor (blue pads). Other end of resistor goes to opto-coupler (K814P). Same circuit is repeated 5 times. These lines will either be open or will receive 220V rms.
The clearance between pad and trace inside the yellow circle is 12 mils. Is it safe?