There's a lot of safety margin built into standard wire insulation. I've exceeded the ratings pretty severely with no ill effects. My concern, were this my project, would be long-term wear on the insulation. 1,000 volts is gonna HURT. 480 hurts bad enough.
line-line potential is 2kV so the wear is worse between conductors. The only saving grace is the current is so low that the wire will see almost no heating which almost eliminates thermal stress.
Am I right then in assuming each wire's insulator provides 600V isolation so two side-by-side would provide 1200V isolation, and the PVC is additional on top of that?
