RadioRA 3

Why Do I Need a Neutral-based Dimmer?

A variety of our dimmers will come in a non-Neutral and Neutral version. You may notice the models with Neutrals will sometimes have a larger list of compatible loads. This article will explain what a Neutral is, what it does for the dimmer, and why it is important for certain loads.

Knowledge Article Contents:

1. What is a Neutral
2. What does it do for my dimmer?
3. What situations will I need it?
4. Related Articles

What is a Neutral

The Neutral wire within a circuit is used to complete the flow of electricity's path. All light fixtures will have a Neutral attached to it as well, as this will be how the electricity completes its circuit back to the breaker. Depending on how your house is wired, you may find Neutral wires present in the wall box when wiring your dimmer, sometimes in a bundle of similar colored wires (usually 2 or more white wires) passing through the back of the wall box. This is primarily found in 'newer' construction after the 1980's, when electrical standards were undergoing a pretty hefty shift.

What does it do regarding our dimmers?

With standard, non-smart switches, the switch will break a circuit, cutting power overall to the light. Smart devices such as our dimmers or system-based switches will need consistent power in order to function properly and respond to commands immediately. Other than the consistent power, Neutrals benefit our dimmers in two different ways:

Dimmers control the frequency the voltage goes through to the lights in order to dim them up and down. When it controls this frequency, the dimmers do 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 will have less of a chance of encountering unexpected flickering, popping on, or other performance issues with the Neutral connected.

The Neutral will also act as a drain for the excess voltage, rather than leaking it to the load itself. Normally, this will not be 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, you will want a Neutral if you are dimming a load, as this will give better dimming performance overall. If you are using LEDs, we highly recommend using Neutral-based dimmers, as 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 type of fixture. 

Related links:

• For more detailed information on how dimming lights works, please see our White Paper regarding dimming transformers: Challenges of dimming whitepaper.
  • This document covers dimming transformers, however it's information is relevant to dimming in general as well. 
• For more information and assistance choosing a Maestro product, please see our Selecting a Maestro Dimmer article
• For more information around compatible LEDs, please see our LED Compatibility Tool