Legrand Power Factor Correction Panel (APFC)

The Legrand Power Factor Correction Panel (APFC) integrates Legrand’s XL³ enclosure family, DPX3 and DRX molded-case breakers, and Viking terminal block systems into IEC 61439-2 type-tested and verified low-voltage switchgear assemblies for reactive power compensation. Designed for commercial distribution and light-industrial applications—office blocks, hospitals, data centers, HVAC plants and retail malls—these APFC units deliver automatic capacitor step switching across 6–14 stages, rated currents up to 800 A per assembly and target power factor setpoints from 0.95 to 0.99. Internal layouts are engineered to comply with IEC 61439 internal separation Forms 1 through 4b, with segregated compartments for busbars, switching devices, and capacitor groups to meet service continuity and safety requirements. Capacitor switching is managed by dedicated power factor controllers compatible with Legrand’s switching contactors and pre-charge resistors to limit inrush. Heavy-duty capacitor contactors are selected and thermal-magnetic protection provided by DPX3/DRX breakers in accordance with IEC 60947-2; capacitor fuse protection follows IEC 60831. For harmonic-rich installations (VFDs, UPS, IT loads), the APFC includes detuned reactor options—commonly 5.67% (tuned to the 5th harmonic) up to 14%—to prevent parallel resonance and to comply with IEEE 519/IEC 61000 harmonic limits. Short-circuit withstand and protection coordination are validated at design stage: typical Legrand-based APFC assemblies are available with type-tested short-circuit ratings suitable for distribution switchboards (configurations commonly rated to 25 kA–50 kA prospective short-circuit current depending on busbar and breaker selection), and coordinated protection curves between DPX3/DRX MCCBs and upstream protection. IP ratings from IP31 to IP42 are standard for indoor distribution; outdoor or plant-floor variants can be specified with higher IP and climatic treatment per IEC 60068 series. Legrand XL³ modular enclosures provide pre-engineered busbar kits, plinths and gland plates, reducing factory build-time and enabling repeatable type-tested results. Viking terminal blocks simplify capacitor wiring and earthing of neutral links, while DPX3 and DRX breakers support selective discrimination, motor protection and earth-fault schemes where required. For benchmarking and system-level comparisons, designers often reference alternative platform architectures such as Siemens SIVACON, ABB MNS or Schneider Electric Prisma Set for larger distribution ratings; however, Legrand APFC assemblies excel in compact commercial panels where modularity and IEC 61439-2 compliance are primary requirements. Typical deliverables include shop drawings, single-line diagrams, manufacturer’s data sheets for capacitors and reactors, coordination study, and verification of dielectric, temperature-rise and short-circuit tests per IEC 61439-1/-2. For hazardous-area or explosion-protected sites, components and enclosures can be selected to meet IEC 60079 series requirements. Contact our engineering team to specify detuning level, step count, and coordination to match plant harmonic profiles and system fault levels.