Dimming - I hear an audible noise from my dimmer or electronic switch

Audible noise is any sound that the eardrum can detect. The range of the sound frequencies normally heard by the human ear spans from 20Hz to 20,000Hz. Niko products are tested for audible noises within this frequency range and pass this quality test. Note that audible noises have nothing to do with electrical radiation and sound does not influence other electronic equipment.

While every 230V powered device is not perfect silent, audible noises with those products are rare. The fact that a noise could be heard depends on three elements.
Firstly, it strongly relates to the individual person hearing the audible noise: because of an increased hearing sensitivity, a young age, the health condition of the person.
Secondly: the environment where the product is installed and the materials used in the room. A possible audible noise will be heard better in a quiet room with for example hard reflecting materials and no curtains. In rare occasions sounds can travel across a building via the electrical cable tubes and are amplified by a wall box.
Thirdly: Other electric devices are used together with a Niko product. A dimmer or transformer is always connected to one or more light bulbs or luminaires. Very often the root cause of the audible noise is linked to a buzzing bulb or the electronics inside a luminaire.

When a Niko universal dimmer (310-0190X, 310-029X1, 310-039X1, 330-0070X, 550-00340, 55X-722X1) is used and a humming sound is heard in a room, then first identify the exact source of the audible noise.

• When the humming sound is originating from the lamp:
  • Humming sound is typically found with CFL lamps or LED lamps but these are not always dimmable. Replace the lamp with a dimmable type if it is not.
  • If the lamp is dimmable then try configuring the Niko universal dimmer with a trailing edge lamp profile, if not done already. Remark: When doing so, and the LED lamp starts flickering at maximum dim level (reason: high capacitive LED lamp) then use lamp profile LED 4. When the light intensity is too low with this lamp profile, then install LED compensator ref. 310-05001 and select profile LED 5, or LED 8 if the boost function is required.
  • If the above actions don’t clear the humming sound, then replace the lamp with a different type. Or the internal lamp electronics such as a transformer or capacitor likely generating electric buzzing. Or the lamp uses long filaments that resonate with the 230V 50Hz mains grid, generating a mechanical buzz. The humming sound of the lamp will typically be loudest at the ‘midpoint’ dim position (half brightness).

     

• When the humming sound is heard from a dimmer:
  • Verify if the electrical load of the lighting circuit is equal or exceeding the minimum load of the dimmer. Increase the wattage when needed by adding bulbs or replace bulbs with a higher electrical load. Always disconnect the mains circuit breaker first.
  • Verify if the maximum electrical load of the dimmer is not exceeded. Decrease the wattage if needed by removing bulbs or replace bulbs with a lower electrical load. Always disconnect the mains circuit breaker first.
  • Double check if all wire connections to the dimmer are tightened up. This to avoid mechanical buzzing
  • Check if the audible noises are originating from another sound source inside the building (example: a technical room, a pump,..), traveling via the electrical wire tubes into the wall box where the dimmer is installed. Switch off the mains circuit breaker of the lighting circuit that feeds the dimmer and verify if the audible noise disappeared. If the audible noise is still heard, then try insulating the wire tube ends inside the wall box or replace the wall box by a variant with sound insulating properties, if this is possible.
  • Verify if the dimmer is compatible with LED loads, in case LED lamps are used. Note that the above-mentioned Niko universal dimmers are LED compatible.
  • Configure the Niko universal dimmer with a trailing edge lamp profile, if not done already. When doing so, and the LED lamp starts flickering at maximum dim level (reason: high capacitive LED lamp) then use lamp profile LED 4. When the light intensity is too low with this lamp profile, then install LED compensator ref. 310-05001 and select profile LED 5, or LED 8 if the boost function is required.
  • Replace the dimmer with a new one if the previous tips didn’t resolve the situation. Always disconnect the mains circuit breaker first.