Harmonic filters and PFC units should be visually inspected at most annually (bonding, terminations, fixings) under a limitation-of-access document, and given programmed maintenance every one to five years with power quality measurements (ENA G5/4-1 for filters; PFC keeping corrected power factor in the stated range with the uncorrected value noted) under a safety document. Where variable speed drives and PFC coexist, resonance risk means PFC protective devices should be exercised at least three-monthly with power factor measured on and off.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.