I installed this dimmer in my bedroom https://i.stack.imgur.com/YR6mq.jpg But when I removed the old switch I only found 2 black copper wires connected to the switch. I proceeded to connect this to the black wires in my dimmer switch and it is working. However, I am concerned about the safety of it. Is connecting only the black wires safe? I did cut out the green wire and made sure they connecting parts are covered with electric tape.
Here is a picture of how it looks now:
I replaced the dimmer with one that have the screwed to hold the wires. It also have a grounding green screw as in the image below.
I still can't tell if I need to attach anything to the green screw. In my apt, look like it's the same namely there is not grounding wires for those switches so I'm assuming the metal box is grounded.