The Lutron Tech Support team has collected a comprehensive list of frequently asked questions. To get started, choose a technical topic from the drop-down menu below.
Lutron dimming technology
The triac is the key to dimming. This dimmer component actually turns light on and off very rapidly – 120 times per second. The longer the light is ON versus OFF, the brighter the light output. By the same logic the longer the light is OFF versus ON, the lower the light output.
When the light is off, no energy is being used. The longer the triac is off, the lower the light output, and the greater the energy savings.
No. No matter how bright or how dim, the light level is constant and smooth. The human eye sees things after they go away. An example of this is in movies where the film is projected on the screen many times a second.
No. Switching the bulb does not decrease bulb life; heat decreases bulb life. By reducing heat, bulb life is increased.
Yes. Dimming increases incandescent lamp life. Halogen lamps are incandescent lamps with a tungsten filament. Lutron's pilot test data suggests that halogen lamps will have an expected lamp life similar to other incandescent lamps when dimmed. As an example, 1 type of halogen lamp with a rated life of 2,000 hrs dimmed to 80 V has a life extension of at least 5 times.
Yes. By using the proper equipment neon/cold cathode lamps can be successfully dimmed. Lutron GRAFIK Eye controls are UL listed for neon/cold cathode loads.
When the Lutron dimmer is set at full, most users will not notice a difference from a switched light. A light meter will register a slightly lower high-end output, as Lutron dimmers automatically save electricity and make incandescent bulbs last longer.
The technical explanation: During normal operation, solid-state dimmers generate heat. A solid-state dimmer is roughly 98% efficient – 2% of the power is dissipated as heat, which causes the dimmer to feel warm to the touch. The closer a dimmer is run to full output and the higher the load (watts) on the dimmer, the warmer it will feel.
This is perfectly normal and safe. Lutron dimmers are designed to the strictest UL safety standard, and can handle their full rated load (a 600 W dimmer can handle a full 600 W of power* without overheating.
*Dimmers that are ganged together in a common wallbox may need to be derated.
Common neutral interaction occurs between at least 2 dimmers that share the same neutral wire. When solid-state dimmers are operating, voltage spikes occur and are transmitted onto the neutral wire. Normally this is of little concern.
When the neutral wire is common (to 2 or more phases of a 3-phase, 4-wire system) the voltage spikes may feed back to the dimmers. The common neutral wire can cause interaction between the dimmers that are on different phases.
The following are symptoms of common neutral interaction:
• Lights flicker at certain dimmer settings
• Lights flash to full output at certain dimmer settings
• Light level of a dimmer on 1 phase inadvertently changes when a dimmer on another phase is adjusted
Lutron recommends the following methods to avoid common neutral interaction:
• Run separate neutral wires for each dimming circuit, from each dimmer's load to the distribution panel
• Install a lamp debuzzing coil Download the Common Neutral Interaction application note (PDF, 17 kB)
RFI is a buzzing noise that may occur in some audio and radio equipment when solid-state dimmers are used nearby. Although every Lutron dimmer contains a filter to suppress RFI, additional filtering may be required in some applications. Typical examples of RFI-sensitive equipment are AM radios, stereo sound systems, broadcasting equipment, intercom systems, public address systems, and wireless telephones. Download Minimizing Radio Frequency Interference application note (PDF, 31 kB)
Installation, applications & maintenance
Yes. When 2 or more dimmers are in the same wallbox, they are considered "ganged". To install ganged dimmers, simply remove the dimmer side-sections from the heat sink. The maximum wattage capacity for each dimmer is reduced (derated) so that the dimmer does not overheat. See Ganging & derating
Transformers may have magnetic (core and coil, toroidal) or electronic (solid-state) clearly indicated on the product. This may not be found on all products. The best way to determine transformer type is to contact the manufacturer.
HINT: Magnetic transformers are often heavy for their size. Electronic transformers tend to be smaller and are often light for their size. Download the low-voltage lighting application note (PDF, 76 kB)
Lutron does not currently recommend using screw-in CFLs ("spiral" or "energy saver" bulbs) with dimmers. Some screw-in CFL bulbs are labeled as dimmable, but their performance does not meet Lutron's high quality standards.
Yes. If a product purchased as a 3-way control needs to be used in a single-pole application, cap off 1 of the traveler wires with a wire connector.
No. 3-way dimmers may only be located in either of the 3-way switch positions.
No. Multi-location dimmers do use standard 3-way wiring, but make use of 1 wire for communications while the other carries the load current. A 3-way switch is not compatible with this.
The common terminal is the different colored screw (not the green).
Yes. A 3-way dimmer will replace 1 of the 3-way switches. A 4-way circuit can be dimmed from all switch locations by using a multi-location dimmer and 2 accessory dimmers such as Rania
Radio Frequency Interference (RFI) occurs when solid-state dimmers emit noise that interferes with AM radios, audio equipment, etc. Every Lutron dimmer includes RFI suppression circuitry. Additional filtering may be required in some applications. In instances where interference does occur, Lutron recommends the following:
• Ensure there is 6' (2m) between the dimmer and audio equipment
• Place the dimmer on a separate circuit than the audio equipment
• Run dimmer wiring in its own metal conduit
• Use a lamp debuzzing coil to filter the RFI
• Purchase an in-line filter for the audio equipment
• Use an electronic low-voltage dimmer (requires a separate neutral wire) for incandescent loads Download Minimizing Radio Frequency Interference application note (PDF, 31 kB)
Occasionally, you may sometimes notice that a lamp is buzzing. This is caused by the lamp filament vibrating as the dimmer rapidly switches the lamp on and off. Lamp buzz is generally noisiest at the mid-range (50%) dimming level. If this happens, use rough service lamps (sometimes called garage door opener lamps), physically smaller lamps, or lower wattage lamps.
The most effective way of reducing lamp buzz is to install a lamp debuzzing coil (LDC) in the lighting circuit. When an LDC is wired in series with the dimmer, it slows down the inrush of current during the rapid switching cycle of the dimmer. As the current inrush is slowed down, the lamp filament vibration and lamp buzz are reduced.
Hi-Power 2-4-6 dimming modules can be added to any incandescent dimmer to increase the load capacity up to 30,000 watts. Lutron also provides GRAFIK Eye dimming panels for load capacity up to 144,000 watts in 1 panel.
You may be experiencing a common neutral interaction. Common neutral interaction is cross talk between dimmers that share the same neutral wire. This may cause the lights to flicker, flash, or suddenly change intensity. When solid-state dimmers are operating, voltage spikes occur and are transmitted onto the neutral wire. Normally this is of little concern, except when the neutral wire is common to 2 or more phases of a 120/208 V, 3-phase, 4-wire system. Under this condition, the voltage spikes may feed back to the dimmers via the common neutral wire, causing interacting between the dimmers.
Lutron recommends the following methods to avoid common neutral interaction:
• Separate neutrals
• Filter choke
• Special Lutron dimmers
Reverse the connections on the Smart Dimmer. (Swap the black and red wires with the connectors from the wallbox.) It is on the load side of the circuit.
If the fixture has a toroidal type transformer (looks like a donut with wires wrapped around it), use a dimmer with a neutral wire.
If your fixture has a "core and coil" transformer (square and heavy), use a lamp debuzzing coil.
These lamps, whether they be termed energy saving or otherwise, are really fluorescent lamps at their heart. Even the ones marked or packaged as dimmable generally exhibit problems with light levels dropping off suddenly when dimming down, or there can be flickering throughout the dimming range. Lutron does not recommend using these bulbs and reminds you that you are already saving energy when dimming your regular incandescent lights.
Lutron dimmers are designed and tested to be installed and operated only in the mounting position (vertical) as indicated on the dimmer.
For this type of installation, cap or remove the dimmer ground wire. A dimmer installed in this manner must be provided with a plastic, noncombustible wallplate (all Lutron plastic wallplates meet these requirements).
Lutron uses tinned copper wires on some of our products. These wires are silver in color as a result of the tinning process. Tinned copper wires are compatible with copper wiring and wire nuts. Lutron uses tinned copper wires to avoid stray strands, and to make our products easier to install.
A "continue hot" wire is 1 of the 2 wires. It's used for a branch circuit. Keep the 2 wires together, and connect both to 1 of the wires on the dimmer.
The blue wire of the accessory dimmer connects to 2 of the wires from the switch (as shown in the dimmer instruction sheet).
All Lutron dimmers have an air-gap off. Typically this is integrated into a slider or paddle switch. Some dimmers have electronics that stay active when the lights are off, such as an infrared receiver. For these products, the air gap is activated by a separate Front Accessible Service Switch (FASS). When open, the FASS completely disconnects the power to the load. This ensures that there is no leakage current to the fixture during routine lamp maintenance. In addition, when the FASS is open, no remote locations (3-way, etc.) can re-energize the circuit.
Yes. Please visit Lutron's glossary of terms
for definitions of lighting industry-specific words and phrases.
CFL/LED Bulb Dimming
No. Standard CFL or LED screw-in replacement bulbs are NOT dimmable. You must use a bulb that was designed for dimming. This information can be found:
- On the bulb’s package and/or
- On the bulb itself
Note: Any bulb that cannot be used on a dimmer will have the statement “not for use with dimmers” marked directly on the bulb.
An LED bulb is a direct replacement for an incandescent/halogen bulb with a screw-in style base. LED fixtures consist of an integral LED driver and engine along with the housing that contains them. The driver is often a separate component mounted on the junction box, similar to a separate fluorescent ballast.
Many fixtures require a separate driver to enable dimming. Lutron offers drivers and dimmers to control these LED fixtures. Go to the LED Product Selection Tool
to determine which Lutron products are approved to control your LED fixture.
Yes, but dimming performance may vary from bulb to bulb due to variances between manufacturers.
Incandescent/halogen bulbs will typically dim lower than CFL or LED bulbs. Most dimmable CFLs will dim down to 10% to 30% measured light output. Please note that the actual dimming range is dictated by the bulb’s circuitry. Choosing the best light source for your application
Dimming range will depend on the LED bulb. Early versions of dimmable LEDs have the ability to dim lower than CFLs and can reach levels as low as 5% to15% measured light. Please note that the actual dimming range is dictated by the bulb’s circuitry.
Yes. Replacing incandescent and halogen bulbs with dimmable CFLs and LEDs saves energy. Dimming them increases energy savings. The more you dim the more you save.
- Confirm that your bulb is dimmable
- CFLs and LEDs are more susceptible to line noise. Please contact Technical Support (800-523-9466) if you think line noise is causing the problem.
The dimming performance of LED lighting can vary greatly from fixture to fixture. Lutron has done extensive testing of LED fixtures on the market and has developed the LED Product Selection Tool
to help simplify the process.
On the selection tool, you will find:
- LED fixtures that are dimmable
- Specific Lutron control(s) that will control that fixture
- Dimming range of the fixture
- Number of fixtures the control can dim
This testing was conducted because dimming performance varies by manufacturer and even within a manufacturer’s product offering. Only by testing can you determine electrical compatibility, dimming performance, and the number of lamps or fixtures that can be used on a dimmer.
An LED bulb is a direct replacement for an incandescent / halogen bulb with a screw-in style base. LED fixtures consist of an LED driver and engine along with the housing that contains them. The driver is often a separate component mounted on the junction box, similar to separate fluorescent ballast.
Some LEDs are designed to replace or install into existing sockets. In these cases extra wiring in the wallbox may be needed if the dimmer requires a neutral connection.
Lutron's Hi-lume A-Series LED driver may require an additional wire going to the fixture to carry the control signal if using 3-Wire models. This wiring may be done using conventional line voltage wiring such as 14/3 romex.
LEDs using low voltage control will need additional wiring, which is often Class 2. Routing this wire has different requirements over conventional line voltage. See application note 213 Combining Low-Voltage and Line-Voltage Wiring Devices in a Multi-Gang Box.
There are no issues with switching LED bulbs with most standard mechanical toggle switches. If the LED bulbs are being switched with mechanical toggle switches with a nightlight or electronic switches, then the bulb must be qualified to work with these types of switches either by the LED bulb or switch manufacturer. The issue is that there is a small amount of off-state leakage current that may cause the load to stay on at a low level even in the off-state.
LEDs can be controlled by many different types of controls and it is up to the manufacturer to clearly define on their packaging which type of control to use with their products. So when a product is said to work with a “standard” or “conventional” dimmer, there is no right answer for which control to use. This may make it difficult to determine which type of control to use with the LED bulb or fixture that you purchased. The LED Control Center of Excellence tests fixtures and bulbs and reports exactly which controls to use. For LED fixture testing results, please visit the LED Product Selection Tool
Dimming range will depend on both the fixture and the control. Many LED fixtures are not capable of being dimmed below 10% measured light level, regardless of the control used. Please see the Lutron LED Product Selection Tool
for specific information regarding the dimming range of a fixture and control combination. Use Hi-lume A-Series LED drivers
for 1% dimming.
Unfortunately “compatible” is a generic term used by many manufacturers, and it has no standard meaning. Lutron has performed extensive testing with each fixture/bulb and control combination to ensure that the solution will provide reliable, smooth, and continuous dimming before recommending it in the LED Product Selection Tool
. Lutron cannot make any recommendations based on what other manufacturer’s print on their instruction and/or specification sheets.
Lutron has tested a significant number of fixtures/bulbs and all findings have been communicated back to the manufacturer of these fixtures/bulbs. Please contact the manufacturer to find out the status.
The manufacturer can submit a request to have their product tested through our website. Lutron will NOT post anything that has not been endorsed by the manufacturer.
Lutron’s LED Control Center of Excellence is available via email (LEDs@lutron.com
) and by telephone, which is staffed from 7am -7pm Monday through Friday. The hotline number is 1 (877) DIM - LED8 or 1 (877) 346 – 5338
There are many benefits of LEDs including:
- Energy efficiency
- Long lifetime (~ 50,000 hours)
- Immediate light output
- Application diversity
- High lumen output
Currently, the light output of an LED averages about 45 to 50 lumens per watt (lm/W), but can reach as high as 100 lm/W and more. An incandescent typically produces 12-15 lm/W, and CFLs can produce at least 50 lm/W.
Measured light is the amount of light as shown on a light meter, whereas perceived light is the amount of light that your eye interprets due to dilation. Twenty percent measured light equals forty-seven percent perceived light.
For more information see Measured_vs_Perceived (PDF, 312 KB)
The energy savings with LED lights is linear unlike with an incandescent. This means that when you dim LEDs to 50% you save 50% energy.
The lifetime of an LED can span from 30,000 hours to 50,000 hours. The typical incandescent bulb lasts about 1,000 hours, while a CFL can last about 10,000 hours, and a linear fluorescent can last more than 30,000 hours. The lifetime of an LED is based on the length of time it can operate at or above 70% of its lumen output.
There are a few failure modes for LEDs, but the most common results in a gradual decrease in the light output. As an LED ages, the amount of light that it produces will slowly decrease. The lifetime of an LED is based on the length of time it can operate at or above 70% of its lumen output.
LEDs do not generate as much heat as an incandescent, but they still generate some heat. In order to ensure a long life, LEDs must be cooled. Many manufacturers provide a large heat sink to reduce the temperature of the LEDs to ensure the rated life expectancy.
LED light sources do not make any audible noise, but the drivers and power supplies for the LED light source may create a hum or buzz. This may occur from using an improper control device. For a listing of Lutron controls that are compatible with the Hi-lume A-Series LED driver, click here
There is an Energy Star rating for LED lamps and for LED fixtures. To be Energy Star compliant many criteria exist, including that the LED must have a power factor of 0.7 or higher. Lutron’s Hi-Lume A-Series LED driver has a power factor of at least 0.95. The LED manufacturer must also state what control types they are compatible with. This statement of compatibility does not, however, mean that the LED will dim very well. For compatibility, it is recommended that you use our LED Product Selection Tool
Part of Lutron's test program is to ensure the product is safe and reliable. The testing program measures several parameters of the fixture and compares these to the standard incandescent load. There are a number of factors at work that may cause a fixture/bulb to behave as a larger wattage load when it is placed on a dimmer. These factors can cause the equivalent wattage of a fixture/bulb to be higher than what is specified by the LED manufacturer. (Basically, a 12W LED bulb might look like much more than that to a dimmer when the LED is dimmed.) These factors include but are not limited to the following:
Repetitive Peak Current - This is the peak amount of current measured on each line cycle when the dimmer turns on. It is determined by changing the dimmer level until the maximum current spike is seen, then recording the peak value. This spike can potentially occur at lower points in the dimming curve. This value is only relevant for leading-edge dimmers.
Inrush Current - This is the peak amount of current measured when the load is turned on at the peak of the line cycle. This value is not relevant for ELV or MLV power supplies that are certified independent of the fixture.
Maximum RMS Current - This is the maximum RMS current measured at any point of the dimming curve. Some LED loads take more current when dimmed slightly than they do at high end or full conduction.
Due to one or more of the above factors having an exceptionally high value, a fixture/lamp when placed on a dimmer may put the stress of a higher rated bulb on the dimmer. The LED Report Cards take these values into account when determining how many fixtures a particular dimmer is capable of handling. Exceeding the recommended maximum can dramatically shorten the life of the dimmer.
Lutron’s LED Control Center of Excellence is available via email (LEDs@lutron.com
) and by telephone, which is staffed from 7am -7pm Monday through Friday. The hotline number is 1 (877) DIM - LED8 or 1 (877) 346 – 5338.
You can contact customer service directly with details of the request. They will help you gather the necessary information and route the request accordingly. Email: firstname.lastname@example.org
For most custom requests, the Custom Controls Group can generate a quote within 24 hours. In the case of a more complex request (i.e. a faceplate that fits over a device from another manufacturer), we will respond within 24 hours, but it may take longer to complete a quote.
Yes, there are many existing Custom Control models available. Selecting an existing Custom Control will help to streamline the process and possibly reduce pricing and lead time. Visit the Custom Controls website to learn more: www.lutron.com/customcontrols
Custom Controls are generally built from non-stocked materials. Pricing and lead time will vary based on quantity of controls requested and availability of materials required for construction. Contact customer service for a quote.
Once a custom design has been reviewed and approved by the customer, the ordering process is exactly the same as a standard product. The custom model number will be entered on the quote by your integrated systems or customer service representative.
The lead time depends upon the complexity of the request. For this reason, every Custom Control must be quoted based on the specific customer requirements. When you receive your quote from the Custom Controls Group, it will contain the price and the lead time to expect once the order is released.
There is no minimum order required for Custom Controls. However, many controls can be offered at a lower price when ordering higher quantities. This is due to price breaks we may get on non-stock materials and custom components that can be passed on to the customer.
Every Custom Control is different and must undergo a feasibility and cost study by the Custom Controls Group. They will evaluate your request and offer alternatives if the complexity exceeds the scope of Custom Controls. Send us your request to start discussing possibilities.
Most orders for Custom Controls also contain standard product. Customer Service will manage communications and ensure that the entire order is processed and tracked appropriately. Customer Service will work as the liaison between the Customs Controls Group and the customer to align expectations and timelines for delivery.
Although there are some limitations, controls from any system (residential or commercial) can be customized in many ways. Unfortunately not all control designs are available for every system type.
Every request for an LED color change must be evaluated on a case-by-case basis. The electrical circuits for each control (seeTouch, Architrave, etc.) need to be analyzed to see if they will support the requested LED color.