THD Compliance Checker

LED drivers do not draw perfectly smooth power — they chop the current, which puts distortion back onto the building's electrical supply. "THD" (Total Harmonic Distortion) measures how much distortion, as a percent. Too much of it heats up wiring and transformers and can draw a utility complaint. IEEE 519 is the industry recommended-practice standard that sets the acceptable limit. You measure THD with a power-quality meter (or read it from the driver spec sheet) and this tool checks it against that limit and totals up your connected load.

When specifying or commissioning a large LED lighting install, or if your utility flags power-quality issues. It is an electrical-compliance check, crop-agnostic. Most reputable horticultural drivers already meet the limit, so this is mainly for large facilities, cheap/unspecified drivers, or a formal utility interconnection.

IEEE 519 Status reads Pass at ≤5% THD, Marginal at ≤8%, and Fail above that — Fail means you should look at active harmonic filtering or better drivers before the utility does. Total Connected Load (kW) and Apparent Power (kVA) size the feed: kVA is always ≥ kW, and the gap widens as power factor drops below 1, so a low power factor means you are drawing more current than the real power suggests. Use the kVA figure, not kW, when sizing breakers and transformers.