We all have a few items on our electrical to-do lists. Whether you’re putting in a light fixture, adding a ceiling fan or cutting in a receptacle, you’re going to need electrical wire ...

My house was built in the 50s, with wiring from that time period. I'm trying to understand how to connect a modern switch up in the place of an existing old one and it just isn't making sense to me.

Concealed. Concealed means that you can run Romex behind walls, floors and ceilings. So, if you're wiring a new house, the NM cable travels within and through the studs behind the drywall.