Annex E
(informative)

Clearance and creepage distance determination for
frequencies greater than 30 kHz

E.1 Clearance

NOTE For frequencies exceeding 30 kHz, an approximately homogeneous field is considered to exist when the
radius of curvature r of the conductive parts is equal or greater than 20 % of the clearance. The necessary radius of curvature can only be specified at the end of the dimensioning procedure.
Figure E.1 – Determination of clearance for frequencies greater than 30 kHz

E.2 Creepage distance

Figure E.2 – Determination of creepage for frequencies greater than 30 kHz

Table E.1 – Minimum values of clearances in air at atmospheric pressure for
inhomogeneous field conditions (Table 1 of IEC 60664-4)

Table E.2 – Minimum values of creepage distances for different frequency ranges
(Table 2 of IEC 60664-4)