Manufacturer Side Note
What is the “extra” blue wire for on this unit?
The 2250AW/RF124 is an "isolated contact" device. That means that the relay is
completely isolated from the voltage that runs the RF124. This gives the device great
flexibility. If it were just a feed-through device, it would be limited in its applications.
But being an isolated contact device, it can be wired "like" a feed-through receiver "OR"
an isolated device. Therefore, it can be installed in such a way so that it draws its power
from a 120v circuit, while controlling another, different circuit (for instance, a 277v
circuit).
The common wiring mistake we often see is that one connects the black and white wires
to line and neutral (black = line, white = neutral) but does not understand how to use the
two blue wires. They will often connect the two blue wires directly to the light bulb (or
other load). They hear the relay activate (click = ON, clunk = OFF), but the bulb does
not 'light'. In essence they have wired one side of the light bulb to the other side of the
light bulb. There is no power.
The two blue wires are connected to the internal relay. When the relay closes, the two
blue wires become a short. The idea is that if the RF124 was being used to control a
"different" 120v circuit, or a 277v circuit, or even a flashlight battery, the unit is to be
wired so that the RF124 electronics is powered by the 120v coming into its black wire
(line), and its white wire (neutral). Then wire "ONE" of the blue wires to the second
voltage source (120v, or 277v or 1½ volt battery), then wire the other blue wire to the
load, then the return wire on the load (usually the white wire coming from the light) goes
back to its return path.
The most common method of wiring the RF124 is to take the black wire PLUS one blue
wire and wire-nut them both to the black "line" wire from the breaker panel. Then wire
the white wire to the neutral and other blue wire to the load.