# Back Can Installation - Retrofit
The T Series and TB Series use the same back cans and are installed in the same way.
Make a 3.5 inch hole in the ceiling at the location you wish to install your light fixture.
Pull your Cat cable into the can through the designated hole.
Slide the back can into your new hole in the ceiling.
Insert clips into the side holes of the back can, from the inside of the can.
Once the backcan is secure, you may now install the fixture by pushing the bulb and its trim into the backcan.