Showerthought: I see a lot of guys not checking the torque on aluminum lugs

I was finishing up a panel change in a 1970s split level last week and the old aluminum feeders were a mess. The lugs were just cranked down, no torque wrench in sight. I pulled out my Wera torque screwdriver set to 35 inch pounds, like the panel label says, and half of them were way over. It matters because over tightening on aluminum can cause the wire to cold flow and loosen over time, leading to hot spots. I've been called back to three jobs this year where the main issue was arcing at a lug, and every time it was aluminum wire that wasn't torqued right. It takes an extra minute per connection, but it stops callbacks. How many of you actually carry a torque tool for resi service work?

3 comments

3 Comments

coleman.gray23d agoTop Commenter

Yeah, that part about cold flow and callbacks... my buddy had a service call last month for a flickering light. Found the aluminum neutral in the meter base was just hanging loose, all chewed up from being over-tightened before.

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nancy81722d agoMost Upvoted

Seen that too. Aluminum's a pain if you don't torque it right.

hannah_perry22d ago

Totally get it, aluminum just keeps moving after you think you're done. I always hit the lugs with a second check after the initial torque, like ten minutes later. It's crazy how much it can loosen up on its own as it settles. That cold flow is no joke, seen it turn a tight connection into a fire hazard real fast.