The second diagram shows how to wire 4 switches to the same light by adding another 4-way switch in series.

You can hook up as many switches as you want by just adding 4-way switches, as long as you have a 3-way switch on each end.

The white neutral wires all tie together to supply the light with a return (neutral) path, and the ground wires all tie together as well.  If the switches have a ground screw, it would be good to connect the bare ground wires to them as a safety factor, but not absolutely essential for the circuit to work.

Just remember that with connecting two 3-way switches, the hot wire goes to one of them and the switch leg goes to the other one, with two travelers in between.

Wiring Diagram: 4-Way Switch (3 switches)

Wiring Diagram: 4-Way Switch (4 switches)

If the power feed (hot wire cable) and the switch leg (light wires) go into the same box, you can connect the wires like this:
Connect the white neutral wire coming from the light, into the white neutral wire coming from the power feed.
Connect the black hot wire from the power feed, to the third leg of the 3-way switch in that box.
Connect the black wire that comes from the light, to the white wires in your travelers.
Connect the white wire from your traveler in the last switch box, to the 3-way switch there.

Since your light can pick up the neutral from the power feed in the same box, the white wires in your travelers can be used to transfer the switch leg to the last switch in your circuit.

BUT – Be careful to mark the white wire you use for this somehow, like with a piece of black tape toward the end.

Click here for a diagram that will give you a basic idea of what I’m talking about.

Here’s a quick video that explains some of those connections:

www.youtube.com/watch?v=pevq0um0Bn8

There are only 2 exceptions that I can think of where you can get things turned around with negative (but not drastic) results, and that’s the sound card connections and the PS/2 ports.

The PS/2 ports are the 2 small round ones with several pins in them.  Your mouse and keyboard plug into these.  Typically they are color coded, but not always.  There is usually a symbol next to them on the back of the case indicating which one goes where.  If you get them switched, no harm done, they just won’t work right.  Just turn the computer off, switch them, turn the computer back on, and they should work fine.

I might add that the connectors need to be turned the right way before pushing them in.  Never force them in.  If they don’t seem to go in relatively easily, inspect the pins to see if any are bent.

Here’s a diagram of the connections on the back of a Dell Dimension:

Wire How To: Single Switch and Light

This is a typical diagram of how to wire a light switch.  There may or may not be a power out line that feeds something else in the circuit, or there may be more than one power out line, depending on what was handy for the electrician at the time.

CAUTION:
DO NOT EVER WORK ON LIVE ELECTRICITY!  ALWAYS TURN OFF THE CIRCUIT BREAKER BEFORE TOUCHING THE WIRES!  EVEN IF YOU TURN OFF THE POWER, TREAT IT LIKE IT IS STILL HOT!  ELECTRICITY CAN KILL YOU!

Ground Wire:
The orange line represents the ground wire.  This is typically the bare wire or sometimes it’s green.  Not all switches have a ground wire connection, but it is a good idea to have it.  Some older homes don’t have a ground wire in the wiring, so it may not apply.  It’s just an extra safety precaution in case the switch breaks on the inside and somehow connects the hot wire to the body of the switch (wouldn’t that be a rude awakening?).  If the ground wire is connected and that happens, the circuit breaker will see a short circuit and kick off.

Neutral Wire:
The neutral wire is the circuit return path and is normally colored white.  All the white wires should be tied together to complete the circuit, and as you can see, there is no connection on the switch for it.  DO NOT connect them to the switch unless you want to see fireworks (or at least a popped breaker)!

Hot Wire:
The hot wire is typically the black wire.  Tie all your hot wires together to feed the other devices in the circuit, except the one going to the light (called the switch leg).  If there are no power out wires in the box, only the one hot wire coming in, you can just connect it directly to the switch.  If there are other power out wires, you will have to tie them all together and cut off a short piece of black wire and connect it in with the others to supply power to the switch.

It’s always a good idea to twist the wires together with your pliers before screwing on the wire nut to ensure a good, solid connection.  It will help to prevent intermittent problems.

Wire How To: Single Switch and Light (alternate)

This wiring diagram is for when your power feed is in the light box instead of the switch box.  You’ll notice the main difference being that you use the white wire in the cable going to the switch box as the switch leg and the black wire as the power feed.

Some electricians will tie the white wire in with the power feed and use the black one as the switch leg, but either way, the switch doesn’t care which is which.

Again, I cannot stress enough to be very careful with your connections here.  If you accidentally tie the white wire from the switch into the other white wires in this configuration, there will be fireworks!

Here’s a wiring diagram of a light circuit with three lights hooked up to one switch and an outlet receptacle in the same circuit.  You can hook up as many lights or receptacles together in this way as the circuit will handle.

Wire How To: Three Lights on a Single Switch and an Outlet Receptacle

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Wiring Diagram: 3-Way Switch

This is a typical diagram of how to connect 2 switches to the same light. It’s especially handy for stairs, hallways, and big rooms.

You will notice that the power feed goes into one switch box, while the switch leg (light wire) goes into the other.  There is also a “traveler” line that connects the two together.

Traveler:
The traveler is a 3 wire Romex cable with a ground.  In other words, there are 3 insulated wires and an uninsulated ground wire.
The ground wire is for added safety and all grounds should be tied together to maintain the safety path.
The white wire is the neutral wire which is the circuit return path for the light.  It also goes to ground, and all white wires should be tied together to maintain the circuit path.
The red and black wires are the travelers that hook the two switches together.  These are attached to the 2 top terminals (or bottom – depending on how you’re holding it).  It doesn’t really matter which one goes where on those 2 terminals.

Wiring Diagram: 3-Way Switch (alternate)

This is an alternate way to wire 2 switches to the same light.  Sometimes it’s more convenient to put both the power feed and the switch leg in the same switch box.

www.youtube.com/watch?v=3fYm7GcuKsE

One of the quickest and easiest ways to increase your computer’s speed and capabilities is to install more Random Access Memory (RAM).