I stopped using wire nuts on a panel in Tucson and the callback rate dropped to zero
Last month I had a job at a house in Tucson where the panel had 14 home runs and I was short on wire nuts, so I used lever connectors on the grounds and neutrals just to finish up. I figured I'd get a callback within a couple months, but six weeks later the homeowner called to say the system had zero faults, which never happens on that old zinc wiring. I went back to check and all the connections were still tight, no corrosion, nothing. Now I'm wondering if I should just switch to levers on every panel or if I got lucky with dry desert air. Anybody run into this on older homes?
Dry desert air is doing a lot of heavy lifting here and that's the part people skip over. In Tucson you got single digit humidity most of the year, so the oxidation that kills connections on old zinc wiring barely gets started. Take those same levers to a house in Houston or coastal Florida and you'd be back in six months looking at green crud on the contacts. Lever connectors hold tight, sure, but they got way more surface area and little springs inside that can trap moisture in a wet climate. The move is probably levers in the desert, keep your usual method where it rains. Weather decides this stuff more than brand loyalty does.