Klein RT390 Circuit Analyzer: My Honest Field Test
I’ve been running the Klein RT390 through its paces for the past three months on residential service calls, and it’s become the first tool I grab when troubleshooting electrical issues. What sets this analyzer apart isn’t just the oversized LCD-though seeing results without squinting in dim crawlspaces is a game-changer-it’s how it handles the messy reality of older home wiring. The voltage drop function has already saved me hours of guesswork on two problematic circuits, and the trip time display gives me actual numbers to show homeowners when their GFCI is borderline. Klein built this thing solid; mine’s survived drops, dirt, and being buried under tools in my van. It’s not cheap, but neither is my time. If you’re serious about electrical diagnostics in HVAC work, the RT390 earns its keep.