We recently removed an old thermostat box and don't need it. There is a long brown thermostat wire now sticking out of the wall, so we want to cap it and push it back into the wall so we can patch and hide the old hole. is that safe? Do I need to cap each wire individually or just place the entire brown wire in a cap and seal with tape?

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    Would you consider installing an old-work electrical box, putting the wire inside of it, putting a blank plate on it and painting it to match the wall? That way the wire could be used in the future if things change again.
    – Smith
    Nov 30, 2022 at 14:24

1 Answer 1


As long as both ends (thermostat and HVAC) are disconnected, nothing else is needed - i.e., you don't need to cap or tape up the wires.

On the other hand, if you have not found and disconnected the HVAC end, do that before sealing up the wall.

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    If it hasn't been disconnected you need to put the wires in a box and cap each wire DO NOT seal them up in the wall it is a safety and fire hazard. Just think if someone years from now pulls the wire and rips of the caps and starts a fire. My HVAC central unit has 120 volts in those little wires. Dec 1, 2022 at 3:37

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