Overheard a customer in Denver say their old system had a hidden battery backup

Troy Clark · 2026-03-13T06:40:08.624666+00:00

I was finishing a panel swap in a Denver home last month and the owner mentioned their old system had a battery tucked inside the wall behind the main unit. They only found it when they remodeled. It made me think, I always check the obvious spots, but now I ask about any past work or hidden panels before I start pulling wire. Has anyone else found a surprise component in a wall during a retrofit?

sandra2035mo ago

@emmasingh, that drywalled intercom is exactly why we scan walls now!

10

raymartin6mo ago

My crew found a live 12-volt transformer buried in a wall in Boulder last spring. We always run a toner on every mystery wire now before cutting. It's saved us from a few nasty surprises with old alarm or stereo systems.

5

emmasingh6mo ago

Wait, you found a whole battery? That's wild. I pulled out an old intercom speaker box last year that was just drywalled over, no sign of it from the other side. The new owners were super confused by the random wires.

1