26
Found out my torque wrench was off by 15 ft-lbs on a panel swap last month
I was double checking some lug connections on a 400 amp panel in a commercial building near Tacoma. Got curious and grabbed a buddy's calibrated torque wrench from his truck. Turns out my old one was reading 340 when it should have been 325. That much difference can cause hot spots over time, especially with aluminum wire. I got mine recalibrated at a shop for $40 but now I wonder how long it was off. Has anyone else had their tools drift like that without noticing?
3 comments
Log in to join the discussion
Log In3 Comments
thomas.parker1mo ago
Gotta love how tools just drift on their own schedule like they've got minds of their own. I've noticed this pattern in all sorts of gear, not just torque wrenches. Calipers, multimeters, even my old tire gauge started reading two pounds low last winter, which made me think my tires were fine when they were actually low. Makes you wonder what else in the garage is quietly lying to you every single day. @the_nina called out the exact difference between over and under torquing, which is a solid point because loose connections get way sneakier than tight ones ever do.
6
the_nina1mo ago
Actually, reading high isn't always fine. In my experience, if it says 340 but it's really 325, that means you're under-torquing everything by 15 ft-lbs. So your connections might be loose, not tight. That's actually worse because loose lugs create high resistance and heat over time. I had a similar thing happen with an old beam style wrench I inherited, it was reading 50 when it was only 45 and I found out after a hot lug started discoloring a breaker terminal.
1