Today I cut off the excess length of HV cable at the controller end which included the suspect portion of cable previously noted but the short did not change.  I inspected the length within the raceway in the VEA but nothing looks suspicious.  Thus, all of the length which is accessible looks unremarkable.  There is still 10'-15' that is within EMT conduit in the VEA that could be exposed if pulled through the conduit body at the exterior wall penetration but other than that there isn't much else to do barring pulling another 900' run of "not free" 10,000V rated cable.  

Recall that the ion pump controller was found tripped off several days ago and could not restart the ion pump do to its power limiting feature and can only achieve 500VDC @ 0.5 amps implying 1000 ohms between HV conductors.  This "shorted" resistance value is duplicated with the "Megger" unit, as well as, with the low voltage VOM which measures 1080 ohms.