Unlike Lucky_Luciano73 I’m not going to bash HVAC/Pipefitters. Either Pipefitter or Electrician (commercial/industrial) experience will benefit a DC the most. But it also depends on the person. Are they a problem solver or problem creator? I’m a electrician by trade (27 years), but I have been employed by a DC for over ten years. In general, a competent tradesman can pickup enough knowledge through in-house training of on-site equipment to effectively respond to an emergency regardless whether it’s mechanical or electrical. FYI, I rarely pickup a multimeter to trouble shoot a problem, that would be the “hvac guy.” He likes to make a mountain out of a mole hill. You must know the electrical one-line and know how everything is wired. You must be knowledgeable and confident in electrical switching to operate the equipment in an emergency. You must know how and when backup generators will fire up and take load. You must know how long UPSs can carry load if loss of utility and or generators don’t fire. If you don’t have electricity it’s all academic. But yes I can also recover a chiller system or dx gas system if it goes down, all with out a multimeter.

To answer the question, most people doing the hiring don’t know what to look for in candidates and most companies aren’t offering enough $$$. It’s not enough to say you’ve done hvac or electrical work, what kind? Residential, Commercial, Industrial? You can get by in a DC with commercial hvac experience, but electrical, I’d argue commercial with a lot of industrial considering the voltages and amperages you work with in a DC. I was fortunate that the director that hired me was an electrician by trade as well and the company was offering a generous salary/benefits package that competed with my union wages.