Sure thing. For a single‑layer board that has to stand a thousand volts you’re looking at a few hard‑core tricks that won’t empty your pocket. First, use a high‑voltage prepreg like FR‑4 rated for 1.5 kV or better, or even a ceramic laminate if you’re really tight on safety. Second, crank up the copper thickness – 4 oz is a sweet spot: it pulls the current out and keeps the trace cool, but still costs less than a double‑layer stack. Third, keep the traces wide and the spacing generous; at 1 kV you want at least 5 mm between conductive areas and a solid 5 mm edge clearance. Fourth, place a solid ground plane on the back side, even if it’s just a thin copper sheet glued to the laminate – that’s the cheapest way to get a true ground return and it helps keep the electric field tidy. Fifth, use a high‑voltage solder mask and a clear, thick epoxy on the top to seal the copper from the environment – no moisture, no corona. And finally, don’t forget to test with a high‑voltage probe before you hit production. That’s about as lean as you can get without compromising reliability. If you want more detail, just ask.

Yeah, a guard ring’s a solid move – just keep it a few mils away and you’ll shave a lot of field stress off that nasty high‑voltage trace. If you can’t fit it on the same side, put a thin copper layer on the back and route the guard on that side. That gives you a real return path and a true ground reference. Also remember the dielectric strength of the prepreg matters; an epoxy prepreg gives you a higher breakdown voltage than standard FR‑4. And if you’re still seeing a spark, just put a 1 kV-rated test pad and pull the probe slow – if it doesn’t catch a spark, you’re good. Anything else you want to tweak?

Got it—keep that guard a tidy 2 mm away, check the corners, and if it still sparks, just swap the prepreg for a ceramic one and you’re golden. Testing is the only way to prove it works, so keep at it.