Using an Industrial Limit Switch to Lock Out Garage Door Opener When the Door Lock is Engaged

It's pretty common to see garage door bolt locks that lock the garage door closed with a pin through the door rail.

Garage Door Bolt

Have you ever accidently actuated your garage door with the lock engaged, and had the opener strain against the locked door? I've done this a few times by accident, and luckily never had any damage to the opener or to the belt. You can install an industrial limit switch to detect that the lock is engaged or disengaged, to protect against damaging the opener. 

I used a Telemecanique XCK-L - you can see the switch label below. Note that it's rated for 10A - less that load of my garage door opener. 

Telemecanique XCK-L Limit Switch with Roller Head

Here's a photo of the limit switch installed - note the roller head depressed by the door lock tab on the right

The limit switch is installed by screwing it directly to the garage door - ensuring that the limit switch is depressed by the end of the lock handle. 

Limit switch with coiled cord running to surface mount electrical box

The limit switch gives you both a normally open (N/O) and a normally closed (N/C) connection. I ran the coiled connection cord to a wall mount electrical box, where I connected the N/O wires to a 14/2 electrical cable. I ran that 14/2 electrical cable back to the electrical outlet near my opener, and used it as a switch wire for one half of the outlet. When the lock is open, it depresses the limit switch plunger, which closes the N/O connection. This allows power to the outlet that the opener is plugged into, and allows the opener to operate. 

 When you close the lock and lock the door, the plunger on the limit switch extends and opens the switch, opening the N/O connection - and disengaging power to the opener outlet. I also added a small lighted adapter so that I can see with a glance whether I have power to the opener outlet.