Current Limiters

Current limiters (voltage reducers) can help you eliminate glare and eye strain as well as the extra cost of overlighting.

Current limiters are devices installed in series with the existing ballast in fluorescent fixtures. The function of the current limiter is to reduce the current before it enters the ballast. As a result, lamps operate at a lower voltage, thus producing less light. Current limiters typically reduce light levels by a fixed amount, unlike a dimmer which can vary the difference in light levels. The energy saved will be directly proportional to the amount of light reduction. For instance, if a current limiter which reduces light output by 30% is installed, then the energy and cost savings will be 30%. Current limiters can reduce light output from 5% to 30%, depending on the particular model installed.

Many older buildings were designed to maintain higher light levels than today's energy standards recommend. Areas which have been redecorated or now operate differently may actually be overlit. Current limiters can reduce the light level in these areas while still maintaining an even light distribution. Some current limiters are permanently wired into the ballast compartment while other models can be fitted into the socket with no wiring changes.

Things to Remember

  • If you have energy efficient fluorescents, check to be sure a current limiter is applicable. Many current limiters can only be used with standard fluorescents designed to operate at full (430 mA) current.
  • Be sure your existing ballasts are designed to deliver full-rated current to the lamp.
  • Current limiters are appropriate for only those areas presently overlit.
  • Light fixtures located in areas that receive substantial daylight are good candidates for current limiters.
  • Some lamp manufacturers' warranties may be voided if current limiters are installed. Install only UL approved devices.
  • Current limiters should be used with electronic ballasts.