I finally learned why old panels have that extra screw hole in the can | Alarm System Installers

Wendy Price · 2026-10-30T10:30:04.619721+00:00

I was pulling out a rusted 12 zone can from a house in Cleveland last month and the homeowner's brother, who did alarms back in the 80s, stopped by and pointed at the little extra hole near the top of the can. He said that hole was for a lock and key back when cans were mounted outside on the wall, so a homeowner could open the box without a tech. I had never thought about that, I just figured it was a punch-out for a knock out or something. He also said some of those old cans had a tamper switch mounted right there, and guys would wire it to a zone so opening the can tripped the bell. I stood there for a second just looking at this rusty box I had pulled a hundred times. It makes me wonder what else on these old installs I have been guessing at all these years. Has anyone else run into the lock and key cans, or was that mostly a Midwest thing?

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I finally learned why old panels have that extra screw hole in the can | Alarm System Installers - Babble Community