CORONA RINGS

[xxjohnh]

It would seem that the use of corona rings on outdoor structures violates the standard NSC phase to phase clearances. Does any one know if the clearances between corona rings outer radius have to meet the normal NSC phase to phase clearances.

 

[Inrushman]

Simply yes, since the corona ring is live at system phase voltage,Phase-to-phase clearance shall be considered out of both rings edge.

 

[jghrist]

What is NSC? Do you mean NESC? NESC doesn't cover Ø-Ø clearances in supply stations, only working clearances. ANSI C37.32 has recommended minimum metal-to-metal clearances and centerline-to-centerline phase spacings.