Are all switches in a 4-way circuit the same?

Question

I have a four way switch in the house (I assume that is the correct term, 4 switches all controling the same light; flipping any one of them toggles the light; no other lights are affected).

I am looking at the wiring diagram (this is an EU one for Belgium) and I see the following symbol for one of the switches:

But other switches have this symbol:

It would seem to me that on an n-way circuit all of the switches would have the same symbol since they all connected to the same number of other switches.

Is this true? Or is there something I don't understand?

If all the switches are the same, on the schematic (that is, the diagram not relating to the physical location of the switches, but just what is on each circuit), is it necessary to repeat the symbol or can you just write "x4"?

batsplatsterson · Accepted Answer

Note - these remarks are from a North American perspective, but I believe switching is done the same way in Europe.

Switch terminology can be confusing but once you understand it, it is pretty simple.

When there's just one switch controlling the lights, it's simple, just a plain switch, labelled ON in the up position, OFF in the down position.  Technically this plain switch is a single pole single throw (SPST) switch but that's not important, nobody uses that term for building wiring.  You turn the switch on, the lights turn on, turn the switch off, the lights turn off.

When you have more than one switch, you want any switch to "toggle" the lights at any time - if they're on, flip any switch and they turn off;  if they're off, flip any switch and they turn on.  As you'd expect, in multi switch circuits, switches are not labelled ON or OFF.

When there's two switches controlling the light, you use two three-way switches.  Flip either switch to toggle the lights.  The switches are called three way switches because they have three terminals to attach wires, not because there are three switches in the circuit.  (Technically a three-way switch is a single pole double throw switch (SPDT) switch but again that term isn't really used in building wiring in North America.  Everyone just calls them three-way switches.)

The wires between the two three-way switches are referred to as "travelers" and the other wire is referred to as the "common."  The diagram shows the logical arrangement of the source power, the switches, and the load.  The physical routing of the wiring may be much different depending how things are laid out.  There are also some special purpose three way circuits that are wired a little differently.

When there's three or more switches controlling the light, you use two three way switches and one or more four way switches.  Four way switches have four terminals.  A four way switch is a variant of a double pole double throw (DPDT) switch, but again that's not really important.

Note that you can have as many four-way switches as you want between the two three-ways at the ends.  You don't use five-way switches for four lights.  The position of the terminals on the switches also varies - you have to check the instructions or markings on the switch to determine how the travelers are connected.

d.george · Answer

Here in the states, a circuit like you are describing would have a 3-way switch on either end and all other switches in between these would be 4-way switches. The electricians will be here shortly with possibly a better explanation and a wiring diagram.

Answered by d.george on October 8, 2020

A. I. Breveleri · Answer

all of the switches would have the same symbol since they all connected to the same number of other switches

This is not true. Two of the switches are each connected to one other switch plus something else, and all the other switches are each connected to two other switches.

In effect the switches are connected in a chain, and together they make or break one path between the ends of the chain. The two switches on the ends of the chain each have another switch only on one side, while all the switches in the interior of the chain each have another switch on either side.

Harper - Reinstate Monica · Answer

This is how multiway switching works.

These are US friendly colors (regardless, colors tend to be a big mess in multiway circuits).  Note the funny switch in the middle; it is different from the switches on the ends.  The diagram may be a little unclear, the switch in the middle has 2 positions, either straight-thru or effectively switching the wires.
There can be any number of middle switches.  Each middle switch either reverses/exchanges the two wires, or sends them straight through.  All wires are always connected.
So yes, a middle switch in a 3+ switch run will be weirder than the end switches.

Peter Green · Answer

The short answer is no, they are not the same.

For the long answer I will break my answer up into three parts. The first will cover terminology, the second will discuss switching a light from two points and the third will cover extending that to more than two points..

A disclaimer: this answer covers traditional mechanical switches, dimmers and "intelligent" switches may use other wiring methods.

There are three different types of switch used in the switching of lighting. The principles are the same on both sides of the pond, but unfortunately the terminology is not.

The first is what British electricians call a one-way switch, American electricians call a two-way switch and electronics guys like myself call a SPST switch. This is a simple on-off switch and is used when there is only one switch controlling the light.

The second is what British electricians call a two-way switch, American Electricians call a three-way switch and electronics guys call a SPDT switch. This is a changeover switch, it has a common terminal which depending on the switch position is connected to one of the other terminals.

The third is what British electricians call an intermediate switch and American electricians call a four-way switch. This essentially acts as a cross-over switch, it has two pairs of terminals and the pairs can be connected either straight-through or crossed-over.

Ok, so how do we use two switches to control the same light? There are basically three methods but one of them has safety issues that mean it is not recommended. All of them use two SPDT switches.

The first method is the simplest to understand. The permanent live is fed into the common terminal of one switch. The light is fed from the common terminal of the other switch. The other terminals of the switches are joined together by the "travelers". When both switches are switched to the same traveler the light is on, when they are switched to different travelers the light is off.

The second method connects all three terminals on one switch to the corresponding terminals on the other switch. One of the non-common terminals is connected to the permanent live while the other feeds the light. When both switches are switched to the incoming live or both are switched to the light then the light is off, when one switch is switched to the incoming live and the other is switched to the light then the light is on.

The third method is to use the switches to switch between live and neutral. The light is connected between the commons of the switches and then the other terminals of the switches are connected to live and neutral. When the light gets two lives or two neutrals it is off, when it gets one live and one neutral it is on. This method is NOT recommended because it can leave the light "off but live" and because it can cause shorts if the switches do not reliably "break before make". As such this method is not recommended (and may well be against regulations, but I have no idea what the regulations are where you live so I can't give advice on that).

To extend the system to more than two locations an "intermediate" switch is needed. This swaps over the two non-common terminals, so the light is on when it would otherwise be on and vice-versa. It can be used to extend any of the schemes mentioned above (though as-before the third scheme is not recommended).

Are all switches in a 4-way circuit the same?

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