Is anyone aware of any manufacture or standards that identify at what ampacity you should or must begin secondary injection testing? To my knowledge this is a decision for the owner. NFPA 70B provides guidance on assessing the power system and environmental factors in an effort to determine what equipment will be injection tested and at what frequency.

I'm not aware of any standards and I believe it is up to the individual designing the maintenance program. I don't recall, but you could try looking at IEEE 493-2007 - IEEE Recommended Practice for the Design of Reliable Industrial and Commercial Power Systems or US Army publication TM 5-698-5. Both have equipment reliability #'s...maybe you can glean something from that.

Mike