IN THE PAST I HAVE ONLY WORKED ON SYSTEMS 600V AND LESS. I AM CURRENTLY WORKING ON 1000V SYSTEM AND NEED TO KNOW IF THE REQUIRED SPACING PHASE-PHASE AND PHASE -GROUND IS GREATER.
THANK YOU

MOELLER;
read about it in 110

Ditto, Sparky, but it is 110-36. I also suggest if you are going to make a habit of over 600V you get a copy of the National Electrical Safety Code, which goes a bit deeper into clearances, also check with OSHA part 1926

Geez fat fingered non proof reading....
110-34