at the end thereof male threads 112 are coated functionally depicted as item c on fig2 with a non conductive coating as is know in the art in a presently preferred embodiment the non conductive coating is a ceramic coating further as is known in the art male threads 112 are sized shaped and configured so that once coated with the non conductive coating the coated male threads 12 mate with corresponding female threads on isolating box connection 108 on box end portion 102 items 108 and 102 not shown on fig2 for clarity but depicted on fig1 b fig2 also depicts isolating ring 106 disposed to be received into ring cutout 110 on isolation portion 105 item 110 described in more detail immediately below although not illustrated on fig2 it will be understood that isolating ring 106 receives a non conductive coating on face surfaces 106 f1 and 106 f2 and on interior surface 106 i in a preferred embodiment the non conductive coating on isolating ring 106 is a ceramic coating it should be noted that testing has revealed that coating the entire isolating ring i e on the exterior ring surface as well as on face surfaces 106 f1 and 106 f2 and interior surface 106 i is not particularly advantageous it has been found that under operating conditions the.