TIL a lot of guys are still using the wrong torque on aluminum lugs

I keep seeing people crank down on aluminum lugs like they're copper, especially on service upgrades. The spec is usually 25 to 30 in-lbs lower for aluminum, but I watched a guy in a training video last month torque a 3/0 AL lug to 350 in-lbs, which is way over. That can cause creep and a loose connection down the line. It's in the NEC and the manufacturer's sheets, but nobody seems to check. Has anyone else had to fix a hot bus bar because of this?

3 comments

3 Comments

keith_rivera193d ago

Saw a melted lug on a panel last year from that exact thing. Started carrying a printed torque chart in my bag to show guys on site. Makes the point better than just telling them.

sean7823d ago

But what if the chart is wrong for the specific lug or material? I've seen guys follow a generic print and still over-torque because it wasn't the right spec sheet. Showing something on paper can make people stop thinking for themselves. Sometimes you gotta explain the why behind the number, not just hand them a number.

grantp281d agoTop Commenter

Good call by keith_rivera19, charts help but you still gotta check the print.