The day my multimeter lied and I trusted it anyway

I was chasing a fridge that kept tripping the breaker in a rental unit in Dayton. I tested the compressor windings with my old Fluke, got a reading that looked fine, and spent two afternoons pulling the start relay and capacitor. Finally the landlord mentioned the tenant had a space heater on the same circuit, and it hit me. I never checked the amp draw under load, only resistance at rest. That meter was fine, my method was the problem. Now I always clamp onto the line and watch the draw when the compressor kicks in. Anyone else ever get burned by a static reading that looked perfect on paper?

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1 Comment

noahhall17d ago

Honestly, that space heater detail is the kind of thing that makes you want to punch a wall. But here’s the angle nobody brings up: you were probably right to trust the meter, because the real problem was the breaker itself. I had a similar deal with a commercial freezer where the static winding test was clean, but the breaker was old and weak, tripping at 80% of its rated load. I swapped the breaker before I even touched the compressor, and the problem vanished overnight. Sometimes the “lying” tool is just the one that can’t measure a tired mechanical part that’s been through a thousand heat cycles. Tbh, the meter told you the truth about resistance, but it can’t tell you the truth about age.