A 2-way dimmer switch is a dimmer that can be used together with a standard 2-way switch, allowing you to control the same lighting circuit from two different locations. A typical example would be controlling the landing or stairway light from both upstairs and downstairs.
There are three main ways in which a 2-way dimmer can be installed.
The first is to connect a single 2-way dimmer to the light without connecting it to any other switch — effectively using it as a 1-way dimmer. This is generally installed in much the same way as a standard 1-way switch. Simply follow the wiring instructions supplied with the dimmer. Please note that some dimmers require a neutral connection. If there is no neutral wire available in your back box, you should choose a no-neutral dimmer.
The second option is to wire one 2-way dimmer together with a standard 2-way switch. This is usually relatively straightforward and is similar to wiring two standard 2-way switches, except that one of the switches is replaced by a dimmer. This is the most common arrangement.
There is, however, one limitation: you can only adjust the brightness from the dimmer. The standard 2-way switch can only turn the lights on and off. If you want to be able to switch and dim the lights from both locations, you will need the third type of installation.
The third option is to wire two dimmer controls together. However, not all dimmers support this type of installation. Dimmers designed for this purpose are commonly referred to as multi-way dimmers or multi-point dimmers. They can be installed at two or more control positions, with dimming and on/off control available at each position.(what is multiway control?)
For example, Repenic's multi-way dimmer supports control from multiple locations and can also be used together with our smart dimmer, combining multi-point control with smart functionality.
Multi-way dimmers must always be wired strictly in accordance with the manufacturer's instructions. Wiring arrangements and operating principles can differ between brands, so the installation method for one manufacturer's system should not be assumed to apply to another.
How does a 2-way dimmer and 2-way switch wiring diagram work?
This arrangement uses two controls to operate the same lighting circuit. One is a dimmer and the other is a standard 2-way switch.
The common terminal is connected as required by the particular circuit arrangement, while two strapper wires run between the two controls, allowing the light to be switched from either position. Brightness can be adjusted at the dimmer position, while the standard 2-way switch provides on/off control only.
Where the faceplate requires an earth connection, make sure that it is correctly earthed. Every conductor must be connected to the correct terminal in accordance with the manufacturer's instructions, and the electrical supply must always be isolated before installation.
A typical wiring diagram is shown below:
How do you safely install a 2-way dimmer?
This type of installation should be carried out by a qualified electrician.
First, isolate the circuit at the consumer unit to prevent the risk of electric shock.
Identify the common conductor, strappers, neutral (where present) and earth conductor in the relevant back boxes. An appropriate voltage tester should be used to verify the conductors and confirm that the circuit has been safely isolated.
Remove the existing switch and identify or label the conductors as necessary.
Following the wiring diagram supplied with the dimmer, connect each conductor to the appropriate dimmer terminal and ensure that the terminal screws are securely tightened.
The switch at the other position remains a standard 2-way switch, with the existing 2-way wiring arrangement retained where appropriate.
Why shouldn't you install two conventional dimmers on the same 2-way or multi-way circuit?
Installing two conventional 2-way dimmers on the same lighting circuit can result in incorrect operation, including flickering, inconsistent dimming or incompatibility between the two controls.
With a conventional 2-way dimmer arrangement, only one position should contain a dimmer, while the other position uses a compatible standard 2-way switch.
The exception is a purpose-designed multi-way or multi-point dimming system, such as the type described above. These products are specifically designed to provide dimming from multiple locations. Their internal electronics and method of communication or control differ from those of conventional dimmers, so the two types are not interchangeable.
What if there is a neutral wire in the back box?
If your dimmer supports a neutral connection, the neutral can be connected to the appropriate terminal in accordance with the manufacturer's instructions.
If the dimmer does not require or provide a neutral terminal — as is the case with Repenic dimmers — the neutral should not be connected to the dimmer. Any unused conductors must instead be safely terminated and insulated in accordance with the applicable wiring requirements.
No-neutral dimmers are particularly useful in older UK properties, where a neutral conductor is often not available at the light switch. Always check the specifications and wiring instructions for your particular dimmer before installation.
Where can I find a reliable 2-way dimmer switch wiring diagram PDF?
Reliable wiring diagrams can usually be found in product manuals, on manufacturers' websites or in reputable electrical installation reference materials.
For Repenic dimmers, our wiring guides and installation videos provide detailed, up-to-date wiring diagrams for the relevant products. If you cannot find the information you need, please contact us through our website's online customer service or by email.
Does Repenic provide wiring support for its dimmer switches?
Yes. Repenic provides wiring diagrams, installation instructions and customer support to help with the correct installation of our different types of dimmers.
Can I upgrade an existing 2-way switch circuit to add dimming?
Yes. In a typical compatible 2-way lighting circuit, one of the existing 2-way switches can be replaced with a suitable 2-way dimmer while the other remains a standard 2-way switch. This gives you dimming control from one position and on/off control from the other.
In many existing installations, this can be achieved using the existing 2-way wiring without running additional cables, although the existing wiring and compatibility should always be checked before installation.