I have a board (Krida electronics, not mine) that uses 2-pole PCB screw terminal blocks with 0.2" (5mm) pin spacing for Line & Neutral input. The conductive parts inside the block are very close together. Worst case scenario, there could be a 0.0275" (0.7mm) air gap between conductive parts. As a hobbyist, this normally freaks me out (I usually leave 5mm air gap for L-N separation).
Is there an equation or UL spec that I can use to calculate if this gap is safe?
Also, before someone suggests this: If this was a permanent installation, I would insulate the terminals with hot melt (assuming the device didn't hear up too much)