items at right are called DUPLEX
RECEPTACLES. They make 120V AC, which is otherwise lethal,
safely available A receptacle has five screws. The
top picture shows two white (plain metallic) screws at center
and a single ground screw (usually green) at right.
The middle picture shows two brass (yellow metallic) screws.
The rules for connecting wires to this unit are straightforward:
black to brass, white to white, ground to green.
It is alliteration; your English instructor will be so pleased.
it is not immediately evident which screws are yellow metallic.
A glance at the bottom picture shows two slots, one being
wider than the other. The wiring rule is white to wide,
more alliteration. More happiness.
screws in each pair of screws are connected by a metal
tab so that when one screw os energized, so is the other..
Thus, an unused pair of screws become useful as a
- On the reverse side of each
unit are four small holes slightly larger than the diameter of
the stripped connecting wire. Upon insertion into the hole,
the wire is held secure by a small spring