> Tesla List wrote: Original Poster: Alex Crow <user-at-alexcrow.clara-dot-net> Welcome to the list Tabraze! Whoa there! The electrode spacing determines purely the *voltage* at which the spark gap fires. *Nothing else*!. In air at ATP, it should be around 0.028 inches per kilovolt for multiple static gaps using 1/4 inch pipe sections. Sorry, I meant 15mm pipe sections or just over 1/2" Alex