I want to replace and old Leviton attic light switch with a Leviton combo switch/outlet. The junction box has two Romex cables in and one out to the current light.
The two in have each a black wire going into to the push-in terminals of the switch and one black one connected to a side screw going to the light. Why would there be two romex cables with two black wires going into the switch? How would I install the combo switch with this wire config? The grounds are just wire nutted together (all three). Thanks for the help.
UPDATE:
Here is a better shot of the back of the old switch with some labels:
CORRECTION... New diagram here:
Based on the updated diagram above... Romex 1 from bottom of box has the shepherd's hook and was attached to the screw... Romex 2 from bottom of box was pushed-in to the bottom of switch... Romex 3 goes to the light through the top of the box from the push-in connection at the top of the switch.
And here is the switch I'm needing to install:
FINAL UPDATE... SUCCESS!!
Thanks to ThreePhaseEel (accepted answer) and Harper.