Wiring Color Codes

for McLean County 4-H Projects

Common colors for DC wire

Black

White

Red

Black wire always to negative terminal

DC Battery Connections

White wire always to positive terminal

DC Connections

Black wires identify negative or hot wires. Switches connect on negative

side of battery to the load (light).

White wire is used to identify the

positive polarity. Black

SwitchWhite

Black

Black

This Knife switch shows black wire in and black wire out.

This type of miniature lamp socket has a brass colored screw and a silver screw. Black wires will connect to brass and

white wires connect to silver.

Red wire is also like black and can be

used to identify the negative side or switch side of a

circuit.

This is a 3-way circuit. Red and black wires are used to identify the path of current and are on the negative side.

RedBlack

Black

WhiteBlack

3-way switch

Black

This is a 3-way/4-way circuit. Red and black wires are used to identify the path of

current and are on the negative side.

The lights are in series. The black wire in between the lights could also be red.

4-way switch

Common Wire for AC

Type 1

Romex Cable

2 conductor with a ground Black

Ground

White

Common Wire for AC

Type 2

Romex Cable

3 conductor with a ground

Ground

Black

Red

White

Ground green

terminal

AC Connections Wiring an Outlet White

silver terminal (neutral)

Black (hot)

Outlet other side: Black wire on brass

terminal (hot)

AC Connections Wiring a Switch

Ground green terminal

Black (hot)

Black (hot)

Neutrals tied together

AC Connections Wiring a 3-way switch

Wiring of a 3-way switch using 3 conductor Romex cable. This is an

exception where white can is terminated on the switch and is a

HOT (live) wire!

A closer look a the 3-way switch. Notice the dark screw, that is the common position.

The other side of the 3-way switch.