help..blown nst

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <steve.tami.andrews-at-att-dot-net>

i think i have just blown my second nst.what am i doing 
wrong,i stopped using the rotary gap and put in a safety 
gap ...from each pole of the nsts to ground,i am 
thinking now that it is a bad thing to use one common 
ground {input sec and safety all grounded together}?one 
nst is ok the other 15000 60ma,good arc to pole from 
ether side one side good arc to ground the other no arc 
to ground.i have not depotted one yet but i dont think 
that will be a prob but i dont know how to go about 
repairing once i get it depotted....thanks alot for all 
your help