Hi all, first-time DIY electrician here. I’ve spent the last week searching internet forums to try and make sure I don’t start an electrical fire at our condo… I figured I should try to pose a few questions here to see if anyone can ease my anxiety.

I am trying to replace a single pole light switch with a Lutron Diva dimmer switch. Easy enough. But when I opened up the existing switch it gave rise to more questions than answers. Please refer to the 1st picture:

1.) There is nothing connected to the ground screw on the existing switch. I used a voltage tester and confirmed that the electric box is already grounded, so I think I am all set and do not need to connect anything to the ground screw on the new switch? Can anyone confirm?

2.) Note the orange and red wires. According to my voltage tester, the red wire is “hot”, the yellow is “not”. Question is: the orange wire appears to be connected to the same terminal as the red one? The orange wire is connected through the push-in terminal while the red is clearly connected via the screw terminal. Is this normal? Or is it possible that the orange wire is a “common wire” but since it is a single pole switch, it is basically useless?

Now please refer to the 2nd picture, which is the installed new dimmer switch. The dimmer switch is currently functional, I just want to make sure what I did is not problematic or dangerous going forward:

3.) Per #1 above, I capped off the ground wire. Is there any danger in doing so?

4.) Since this is a single pole situation, I also capped off the red and white striped wire (which should be used for the common wire, if applicable). Any danger in leaving this one capped?

5.) The mysterious orange wire – I also capped this one since I didn’t know what else to do with it. Any risk or dangers associated with leaving this one capped if it is actually a hot wire?

6.) Finally – I connected the red wire coming in from the wall (the hot wire) to the black wire on the switch, and connected the yellow wire coming from the wall (not hot) to the red wire on the switch. This means there are only 2 wires from the wall connected to 2 wires on the switch, which, according to the installation instructions is all I need.

Apologies in advance for the long-winded novel! Like I said, I am absolutely a beginner with this stuff and am generally paranoid about starting an electrical fire at our house! Thankful for any help or insight you guys can provide!