Installation – circuit with 2 switches (3-way) – INSTEON SwitchLinc Dimmer 100-277VAC (dual band) (2478D) Manual User Manual
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Page 6 of 19 2478D - Rev: 1/21/2014 7:32 AM
Installation – Circuit with 2 Switches (3-way)
Circuits with 2 switches are called 3-way circuits. Both switches in a 3-way circuit need to be replaced by 
SwitchLincs (and/or KeypadLincs). 
 
Note: 3-way circuits require a pair of wires called Travelers between joining wall boxes to operate. 
INSTEON switches, dimmers and keypads do not require both Traveler wires for 3-way circuits to 
function. Simply wire one to Line, Neutral and Load; the other(s) to Line and Neutral. Use one Traveler to 
share Line between boxes. Adding both SwitchLincs to a Scene creates a virtual 3-way circuit. 
 
1) Turn off circuit breaker(s) and/or remove fuse(s) feeding wall boxes 
2) Use a voltage meter to verify that power is off 
3) Pull both switches from their wall boxes, each existing 3-way switch will have no less than 3 wires 
4) Remove wires from existing switches 
5) Make sure wires are safely separated from each other and turn breaker(s) back on 
6) Using a voltage meter measure each wire to Ground in both boxes until you find the single wire 
supplying 100 - 277VAC (Line)
a. We will now refer to that location as box 1 
b. The other box will have the Load wire. That will be box 2 
7) Turn breaker(s) back off 
 
 
In Box 1 (Line box) 
8) Connect bare Ground wire from the 
SwitchLinc to bare Ground wire or Ground 
screw in wall box 
9) Connect White Neutral wire from SwitchLinc
to Neutral wire(s) in wall box (usually white)
10) Using a wire nut, cap the Red wire from
SwitchLinc
11) Connect Black wire from Switch Linc to 100 -
277VAC Line wire in wall box (usually Black) 
along with one Traveler wire running between 
boxes (preferably Black). Note color of 
Traveler you are using as this will carry Line 
voltage to box 2. 
12) Cap unused Traveler 
 
 
In Box 2 (Load box) 
13) Connect bare Ground wire from 
SwitchLinc to bare Ground wire or 
Ground screw in wall box 
14) Connect White Neutral wire from
SwitchLinc to Neutral wire(s) in wall 
box (usually White) 
15) Connect Red wire from SwitchLinc to
Load wire (usually Black)
16) Connect Black wire from SwitchLinc to
same color Traveler from box 1 
carrying 100 - 277VAC Line (usually 
Black) 
17) Cap unused Traveler wire 
18) With the LED bar on the left, gently 
place both SwitchLincs into the 
junction boxes and screw in place 
19) Turn breaker(s) On