Power Quality Checklist

Verify nominal voltage is within ±5% of rated voltage

Check voltage balance between phases (should be <2%)

Monitor for voltage sags/dips during compressor startup

Measure voltage THD (Total Harmonic Distortion) - should be <5%

Verify current draw is within equipment specifications

Check current balance between phases (should be <10%)

Measure current THD - should be <15% for VFD equipment

Check power factor (should be >0.85)

Verify harmonic filters are installed and operational

Confirm line reactors are present on VFD inputs

Check DC chokes or equivalent harmonic mitigation in VFDs

Measure ground resistance (should be <5 ohms)

Verify proper bonding of equipment to ground

Confirm surge protection devices are installed and functional

Test GFCI/RCD protection where required

Verify UPS capacity is sufficient for connected load

Check UPS battery condition and runtime

Test automatic transfer switch operation

Verify generator maintenance status (if applicable)

Power Quality Maintenance Checklist