Rant: 10 years of torquing lugs wrong until a foreman called me out

Honestly, I spent a decade just cranking down on panel lugs with an impact driver like a total hack. Last Tuesday I was finishing up a 200-amp service swap at a strip mall off Route 9 and an old foreman walked by. He watched me for a second and asked if I ever read the torque specs on the breaker. I grinned and said not really, thinking he was just busting my chops. Then he pointed at the terminal and said the heat damage alone probably cost the building owner $300 a year in extra power draw. I grabbed my torque screwdriver and set it to 45 in-lbs like the sticker says on the GE panel cover. Turns out I had been over-tightening everything for years, crushing wires and creating hot spots. Has anyone else had one of those forehead slap moments where a basic code rule smacks you in the face after a decade of ignoring it?

3 comments

3 Comments

stone.thomas1mo ago

Bro that foreman was doing you a solid. Did you actually check the wire after you backed out the screws though? I had a similar wake up call a few years back when I pulled a lug off a 200A main and found the copper strands were actually flattened out and starting to crack from me cranking on it with an impact for years. Never even thought about it until I saw the damage with my own eyes. How bad was the crush damage on the wires you had tightened before?

the_vera1mo ago

450 in lbs? That's wild. I never even look at those stickers.

grantthomas1mo ago

I see it a little different, stone.thomas. Over-tightening is definitely bad, but I have to wonder how much of that extra draw is real versus the foreman just trying to make a point. I’ve pulled apart plenty of connections that were cranked down tight and they looked fine, no real damage. Maybe we just need to find a middle ground, not be lazy but also not freak out over every inch-pound.