And anyone wanting to install smart switches or anything that involves working with AC home wiring, TURN OFF the power at the breaker.
Home AC power will kill you if you get a good enough contact with the wires ever for a very short time.
You also can cause a short if the hot and ground touch each other they can then weld them selves together and cause the whole wire run to heat up and melt causing a fire anywhere in the walls. This has happened to a friend of mine many years ago, and it cause severe damage to their home. Most homes do not have GFCI (ground fault circuit interrupter) or AFCI (Arc Fault circuit interrupter) breakers. Those type of breakers only started being installed in very modern or high end homes only in recent years i read. Standard breakers only trip when there is a overload condition, when too many AMPs are being pulled than the breaker is rated for, which is different than a ground or arc fault.