Safety & Compliance Forum

Scope and object
This part of IEC 60664 deals with insulation coordination for equipment within low-voltage systems. It applies to equipment for use up to 2 000 m above sea level having a rated voltage up to a.c. 1000 V with rated frequencies up to 30 kHz, or a rated voltage up to d.c. 1500 V.
It specifies the requirements for clearances, creepage distances and solid insulation for equipment based upon their performance criteria. It includes methods of electric testing with respect to insulation coordination.
The minimum clearances specified in this standard do not apply where ionized gases occur.
Special requirements for such situations may be specified at the discretion of the relevant technical committee.
This standard does not deal with distances
– through liquid insulation,
– through gases other than air,
– through compressed air.
NOTE 1 Insulation coordination for equipment within low-voltage systems with rated frequencies above 30 kHz is given in IEC 60664-4.
NOTE 2 Higher voltages may exist in internal circuits of the equipment.
NOTE 3 Guidance for dimensioning for altitudes exceeding 2000 m is given in Table A.2.
The object of this basic safety standard is to guide technical committees responsible for different equipment in order to rationalize their requirements so that insulation coordination is achieved.
It provides the information necessary to give guidance to technical committees when specifying clearances in air, creepage distances and solid insulation for equipment.
Care should be taken to see that manufacturers and technical committees are responsible for application of the requirements, as specified in this basic safety publication, or make reference to it, where necessary, in standards for equipment within their scope.
In the case of missing specified values for clearances, creepage distances and requirements for solid insulation in the relevant product standards, or even missing standards, this standard is applicable.