House Electrical Wiring Diagrams:
Wiring Connections in Switch, Outlet, and Light Boxes

The following house electrical wiring diagrams will show almost all the kinds of electrical wiring connections that serve the functions you need at a variety of outlet, light, and switch boxes. It gives you over 200 diagrams. For help understanding them, be sure to open the Explanation page. Also consider taking the Connections Tutorial or seeing the Typical circuit diagram.

EXTENSIVE Box-and-Cable Connection Diagrams

  1. How many separate cables (not wires) come into the box for your outlet, switch(es), or light?
  2. How many wires are in each of these cables (don't count grounds, which are bare or green)?
According to your answers to these questions, click the appropriate graphic below to expand it, but keep this Explanation at hand.

Hooking up a single romex- thumbnail
Only one 2-wire (flat) cable ["14-2" or "12-2"]
Red wire in a cable- thumbnail
Only one 3-wire (round) cable ["14-3" or "12-3" (w/red wire)]
Two black and two white wires- thumbnail
Two 2-wire cables
Two black, two white, one red wire- thumbnail
One 2-wire cable and one 3-wire cable
Two circuits in one box- thumbnail
Two 3-wire cables
Hook up three romex in a box- thumbnail
Three 2-wire cables
Two flat and one round electrical cable- thumbnail
Two 2-wire cables and one 3-wire cable
Two red wires in an outlet box- thumbnail
One 2-wire cable and two 3-wire cables
Wire connections for three round cables- thumbnail
Three 3-wire cables
How to connect four romex- thumbnail
Four 2-wire cables
Several romex cables to hook up- thumbnail
Three 2-wire cables and one 3-wire cable

Be sure to open the Explanation (new window) to understand the functions of the cables.

Connections Tutorial
Sitemap of all diagrams