MT 1 - TC 109/MT 1

IEC 60664-1:2020 deals with insulation coordination for equipment having a rated voltage up to AC 1 000 V or DC 1 500 V connected to low-voltage supply systems. This document applies to frequencies up to 30 kHz. It applies to equipment for use up to 2 000 m above sea level and provides guidance for use at higher altitudes. It provides requirements for technical committees to determine clearances, creepage distances and criteria for solid insulation. It includes methods of electrical testing with respect to insulation coordination. The minimum clearances specified in this document do not apply where ionized gases are present. Special requirements for such situations can be specified at the discretion of the relevant technical committee. This document does not deal with distances:
– through liquid insulation;
– through gases other than air;
– through compressed air.
This edition includes the following significant technical changes with respect to the previous edition:
update of the Scope, Clauses 2 and 3,
addition of 1 500 V DC into tables,
new structure for Clauses 4 and 5,
addition of Annex G with a flowchart for clearances,
addition of Annex H with a flowchart for creepage distances,
update of distances altitude correction in a new Table F.10.
It has the status of a basic safety publication in accordance with IEC Guide 104.
The contents of the corrigendum of October 2020 have been included in this copy.

IEC/TR 60664-2-1:2011, which is a technical report, serves as an application guide for technical committees and manufacturers specifying dimensioning requirements for products in accordance with the IEC 60664 series. The significant items for consideration are as follows:
a) nominal system voltage(s) or rated insulation voltage(s);
b) overvoltage category of the products (OV cat.);
c) any type of overvoltages;
d) frequency of the voltage;
e) characteristics of the solid insulating material;
f) pollution degree and humidity levels.
The main changes with respect to the previous edition are listed below:
- the previous edition was only an application guide for IEC 60664-1. This second edition takes into account not only IEC 60664-1 but also the other parts IEC 60664-3, IEC 60664-4, and IEC 60664-5 and their interrelation;
- principles of the IEC 60664 series for insulation dimensioning of LV equipment are explained and examples of practical application are provided together with some background information;
- Annex A provides an overview of clauses of IEC 60664-1 requiring decisions by technical committees, or specification of options, or requiring activities of the manufacturer;
- Annex B provides an overview of such clauses of IEC 60664-4;
- Annex C provides an overview of such clauses of IEC 60664-5;
- Annex D amends the tables of Annex F of IEC 60664-1:2007 with rated impulse voltages for voltages line to neutral derived from nominal d.c. voltages up to and including 1 500 V.
The contents of the corrigendum of October 2011 have been included in this copy.

IEC TR 60664-2-2:2002(E) Provides an overview of the different kinds of surge overvoltages that can occur on low-voltage installations and equipment. In particular:
- the magnitude and duration of typical surges as well as their frequency of occurrence;
- information on overvoltages resulting from interaction between power and communication systems;
- guidelines when considering interface issues in relation to insulation coordination;
- guidelines concerning surge protection means on the basis of availability and risk considerations, including interaction within the system;
- highlights temporary overvoltages and other factors that have to be taken into account for insulation coordination, primarily related to protective control using surge protective devices.