Clearance and creepage selection method
IEC 60664-1 selects clearance and creepage from different electrical and environmental inputs; neither distance is calculated from one universal algebraic formula.
Clearance = f(Uimp, field, altitude, insulation)Creepage = f(Uworking, pollution degree, CTI group, insulation)daltitude = dtable × Kaltitudedreinforced,creepage = 2 × dbasic,creepagewhere:
- Uimp
- Rated impulse withstand voltage[kV]
- Uworking
- Highest working RMS or DC voltage across the insulation[V]
- CTI
- Comparative tracking index of the insulating material
- Kaltitude
- Altitude correction factor above the reference altitude
- dtable
- Distance selected from the applicable standard table[mm]
The lookup result is limited to the stated IEC 60664-1 conditions. Product standards and construction details can require larger distances or additional tests.
How to use the Clearance & Creepage Calculator
Estimate IEC 60664-1 minimum clearance through air and creepage along an insulating surface from voltage, overvoltage category, pollution degree, CTI group, insulation level, and altitude. Start by choosing the operating mode, then enter values from nameplates, measurements, or project documents in the units shown. The result updates immediately and keeps intermediate quantities visible for review.
- Confirm the system and calculation mode.
- Enter measured or manufacturer-rated values.
- Review the primary result and intermediate metrics.
- Continue with the related protection or equipment-selection checks.
Calculation method and validation
The equations and symbol definitions above show the complete calculation basis. Inputs are checked before calculation so zero, negative, incompatible, or physically impossible combinations are flagged instead of silently producing a misleading result.
How to interpret the result
Use the main result as a starting value and read every supporting metric. IEC 60664-1:2020 general low-voltage insulation-coordination workflow Inhomogeneous electric field Frequency not above 30 kHz Air at normal atmospheric composition Publicly verifiable lookup range: PD1/PD2, 63–1000 V working voltage, impulse levels through 6 kV A passing or recommended result means the entered mathematical conditions are satisfied; it does not certify the complete installation or a particular product combination.
- IEC 60664-1:2020 general low-voltage insulation-coordination workflow
- Inhomogeneous electric field
- Frequency not above 30 kHz
- Air at normal atmospheric composition
- Publicly verifiable lookup range: PD1/PD2, 63–1000 V working voltage, impulse levels through 6 kV
Selection limits and next checks
Use the applicable product standard when it specifies different or additional requirements. PD3, PD4, coated assemblies, frequencies above 30 kHz, ionized gas, liquids, compressed air, and special atmospheres require a separate standard assessment. A calculated distance does not validate production tolerances, slots, ribs, coatings, solid insulation, or dielectric testing. Compare the output with the current applicable standard, local rules, exact VIOX product datasheet, environmental conditions, protection coordination, and the engineer's project requirements before procurement or installation.
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Assumptions
- IEC 60664-1:2020 general low-voltage insulation-coordination workflow
- Inhomogeneous electric field
- Frequency not above 30 kHz
- Air at normal atmospheric composition
- Publicly verifiable lookup range: PD1/PD2, 63–1000 V working voltage, impulse levels through 6 kV
Important Warnings
- Use the applicable product standard when it specifies different or additional requirements.
- PD3, PD4, coated assemblies, frequencies above 30 kHz, ionized gas, liquids, compressed air, and special atmospheres require a separate standard assessment.
- A calculated distance does not validate production tolerances, slots, ribs, coatings, solid insulation, or dielectric testing.