Warning: That cheap multimeter from Harbor Freight almost cost me a compressor

Picked up one of those free Harbor Freight meters a few years back just for quick checks. Last month I was testing a fridge compressor and it read 3 ohms, so I called it good. Put the new start relay on and the compressor locked up after 10 minutes. Grabbed my Fluke and it showed 0.8 ohms which is way too low. That freebie meter couldn't read low resistance accurately at all. Anyone else had a cheap tool nearly blow up a job?

2 comments

2 Comments

hugo_jones215d ago

I get what you're saying but I see it different. That meter read 3 ohms and your Fluke read 0.8 ohms. 3 ohms is still low resistance. Most compressors will pull a start relay with anything under 5 or 6 ohms. The real problem is you didn't know your meter was off. Every cheap meter has a tolerance rating. You gotta check them against a known resistance before trusting them on something critical. That's not really the meter's fault.

nathan_patel15d ago

That's not really the meter's fault" is exactly right, people blame the tool when they didn't check it first. A cheap meter is fine for basic stuff if you just test it against a known resistor or even a wire with a known length every now and then. A few minutes of checking saves you from chasing ghosts and blaming the wrong thing.