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Lutron manufactures neutral and non-neutral versions of dimmers. You may notice that models with neutrals often have a larger list of compatible loads. 

This article details what a neutral is, what it does for the dimmer, and why it is important for certain loads.

Skip To: What is a Neutral? | What Does a Neutral Connection Do On Lutron Dimmers? | What Should I Use a Neutral-Based Dimmer? 

What is a Neutral?

The Neutral wire within a circuit completes the flow of electricity's path. Depending on how your house is wired, neutral wires may be present in the wall box when installing your dimmer.

Typically neutral wires are found in a bundle (usually 2 or more white wires) passing through the back of the wall box. This is primarily found in residential construction after the 1980s when electrical standards were undergoing a significant shift.

What Does A Neutral Connection Do On Lutron Dimmers?

Standard (non-smart) switches break a circuit, cutting power overall to the light. Lutron smart devices, such as our dimmers or system-based switches, require consistent power to function properly and respond to commands immediately. Aside from the consistent power, neutrals benefit our dimmers in two different ways:

Dimmers control the frequency the voltage goes through to the lights to dim them up and down. When it controls this frequency, the dimmer does not have any reference to where the waves begin and end. The neutral gives the dimmer what is called a Zero-Cross reference. This allows the dimmer to control the dimming range of the lights more efficiently, as well as have better overall performance for different types of loads. In most cases, you have less of a chance of encountering unexpected flickering, popping on, or other performance issues with the neutral connected.

The neutral also acts as a drain for the excess voltage, rather than leaking it to the load itself. Normally this is not noticeable, however, if the lights are sensitive to any voltage (most commonly LEDs), you will see them react to this 'leak' by the light not fully turning off when it should be fully turned off. When a Neutral is connected, it prevents that leak by giving the internal components of the dimmer a separate 'path' to send that leak of energy to not interact with the lights at all. 

When Should I Use a Neutral-Based Dimmer?

In most cases, a neutral is recommended when dimming a load as neutral-based dimmers have better dimming performance overall. Additionally, LED lights are extremely sensitive and react to nearly any voltage routed to them compared to incandescent or halogen bulbs. This excess voltage, mentioned above, can create an effect known as 'Ghosting', where the LED will never fully turn off but will still be on at varying levels depending on the model of the LED and the type of fixture. Lutron recommends using neutral-based dimmers when controlling LED lighting loads.

Related Links

For more detailed information on how dimming lights works, please see our White Paper regarding dimming transformers: Challenges of Dimming Whitepaper.

To find a list of compatible LEDs for your Lutron dimmer please see our LED Compatibility Tool.