4 Way Switch Wiring Methods
When you only need one switch to manage a light, then you’d use a single pole switch.
Should you need 2 switches to control a light then you would use two 3way switches.
In case you need three switches to manage a light then you’d use two 3ways with one 4way.
If you still need more switches just add 4ways. Need six switches? Use two 3ways with four 4ways.
Weather you use one 4 way or more, the 4 way will not work without two 3 ways.
A 4way switch has 2 “IN” terminals and 2 “OUT” terminals. They are identified on the switch with the words “IN” and “OUT” or there might be 2 marks identifying a pair of terminals as either “IN” or “OUT” The 2 traveler wires from one 3way are connected to the 2 “IN” screws or the 2 “OUT” screws but never one traveler to “IN” and the other to “OUT”
S4 Method #1 Basic 4Way
That is the perfect and easiest method of wiring 4 way switches.
Should you only learn one 4 way method, learn this one.
Rating Excellent A+ br> Probably the most simple and trouble free 4 way method.
Level Intermediate. It’s also called a “Plain Jane 4 way”
Description Same as 3way Method #1 but add a 4way switch into the traveler wires between the two 3ways. A 2 wire (14/2, 12/2) feed is pulled from the closest source of power like a receptacle to the primary 3way switch box. Then a 3 wire (14/3, 12/3) is run between switches, from the first 3way to the 4way to the second 3way. Finally a 2 wire switch leg is pulled from the last 3way to the nearest light and then to another lights which are supposed to come on with these switches.
L1 = hot, C = common, T = traveler terminal, IN = the IN terminal on a 4way switch, OUT = the OUT terminal on a 4way, and N = neutral.
L1 C1 2 4 7 9 C10 11 12 N
Current begins at L1 and flows through the wire to C terminal on the primary 3way switch. Inside the switch it flows through the switch blade (purple) from C1 to 2. It then leaves the 2 terminal and follows the (red) wire to IN terminal 4 on the 4way switch. Contained in the 4way current moves through the (purple) switch blade from 4 IN to 7 OUT terminal (never IN to IN or OUT to OUT) It leaves the 7 OUT terminal and follows the black wire to the 9 terminal on the last 3way switch. Contained in the 3way it flows from 9 to 10 Common. It then leaves the 10 C terminal and follows the (black) switch leg wire to the 11 terminal on the light where it connects to a small point on the bottom shell of the sunshine bulb. Inside the light bulb current flows through the filament wire to the base shell where it connects to terminal 12. From 12 current heads back to the source through the neutral wire to N.
The part that isn’t shown is how current continues from the N (neutral) to a transformer coil, through the coil to L1 (hot) where it starts yet again.
As mentioned at the highest, it will be important to note how the 3way and 4way terminals make connections in several positions of the switch. In 4ways In’s connect with OUT’s but never to one another (unless the switch is defective).
In 3 ways Travelers connect to the Common but never to one another. Discuss with the drawings above;
On the S4; 4IN connects to 6OUT or 7OUT but never the opposite IN number 5
5IN connects to 6OUT or 7OUT but never the opposite IN number 4
6OUT connects to 4IN or 5IN but never the other OUT number 7
7OUT connects to 4IN or 5IN but never the opposite OUT number 6
On the S3; 10 Common connects to eight Traveler or 9 Traveler but 8 and 9 never connect together.
S4 Method #2 Dead End 4way With Extended Switch Leg
Rating Above Average B br> This method is commonly used by professional electricians
Description Power and switch leg at one 3 way and the dead end of a 3 wire at the other 3 way. When wiring a dead ends you’ve gotten a choice of which wire to increase over to the common on the dead end 3way switch:
– either extend the black switch leg from the sunshine
– or extend the black hot (L1).
In this example the switch leg is extended over to the common on the dead end 3way.
S4 Method #2.1 Dead End 4way With Extended Hot
Rating Above Average B br> Level Intermediate
Description Power and switch leg at one 3 way and the dead end of a 3 wire at the other 3 way. The travelers are the same as S4 Method #2, the neutral is identical, the one change in wiring is the hot is extended over to the dead end 3way’s common instead of the switch leg. Compare the L1 wire in this method with the L1 wire in S4 Method #2 above.
S4 Method #3 Double Dead End 4way
Rating Average C+ br> Level Advanced Also called a “Switch Leg and Feed at the 4way”
Description Everything is pulled to the 4way switch box;
✓the feed, ✓the switch leg from the light, ✓a 14/3 from one dead end 3way and
✓another 14/3 from the 2nd dead end 3way.
The recent is extended to at least one 3way and the switch leg is extended to the other 3way.