Yeah, hitting 500 is wild. @margaretr76, you mentioned the iron temp, and that's key. I mean, what temp do you actually set it to for a Berber, and do you change it based on the backing material? I've found that makes a bigger difference for long term hold than just the melt check.

My last client took eight drafts just to pick a shade of beige.

Honestly, I'm with the old foreman on this one. The code might say it's okay on paper, but I've seen those screws strip out or come loose with two wires way too many times. Just because the book allows it doesn't mean it's a good idea. A single wire per terminal is just cleaner and you never have to worry about it. Sometimes the old school way is just better practice.