scope:

Scope and object

This part of IEC 60947 applies to CONTROL CIRCUIT DEVICES and SWITCHING ELEMENTS intended for controlling, signalling, interlocking, etc., of switchgear and controlgear.

It applies to CONTROL CIRCUIT DEVICES having a rated voltage not exceeding 1 000 V a.c. (at a frequency not exceeding 1 000 Hz) or 600 V d.c.

However, for operational voltages below 100 V a.c. or d.c., see note 2 of 4.3.1.1.

This standard applies to specific types of CONTROL CIRCUIT DEVICES such as:

- manual control switches, for example PUSHBUTTONS, ROTARY SWITCHES, FOOT SWITCHES, etc.;

- electromagnetically operated control switches, either time-delayed or instantaneous, for example contactor relays;

- PILOT SWITCHES, for example pressure switches, temperature sensitive switches (thermostats), PROGRAMMERS, etc.;

- POSITION SWITCHES, for example CONTROL SWITCHES operated by part of a machine or mechanism;

- associated control circuit equipment, for example INDICATOR LIGHTS, etc.

NOTE 1 A CONTROL CIRCUIT DEVICE includes (a) CONTROL SWITCH(ES) and associated devices such as (an) INDICATOR LIGHT(S).

NOTE 2 A CONTROL SWITCH includes (a) SWITCHING ELEMENT(S) and an actuating system.

NOTE 3 A SWITCHING ELEMENT may be a CONTACT ELEMENT or a SEMICONDUCTOR ELEMENT.

It also applies to specific types of SWITCHING ELEMENTS associated with other devices (whose main circuits are covered by other standards) such as:

- auxiliary contacts of a switching device (e.g. contactor, circuit breaker. etc.) which are not dedicated exclusively for use with the coil of that device;

- interlocking contacts of enclosure doors;

- control circuit contacts of ROTARY SWITCHES;

- control circuit contacts of overload relays.

Contactor relays shall also meet the requirements and tests of IEC 60947-4-1 except for the utilization category which shall comply with this standard.

This standard does not include the relays covered in IEC 60255 or automatic electrical control devices for household and similar purposes.

The colour requirements of INDICATOR LIGHTS, PUSHBUTTONS, etc., are found in IEC 60073 and also in publication 2 of the International Commission of Illumination (CIE).

The object of this standard is to state:

a) The characteristics of CONTROL CIRCUIT DEVICES.

b) The electrical and mechanical requirements with respect to:

1) The various duties to be performed.

2) The significance of the rated characteristics and of the markings.

3) The tests to verify the rated characteristics.

c) The functional requirements to be satisfied by the CONTROL CIRCUIT DEVICES with respect to:

1) Environmental conditions, including those of enclosed equipment.

2) Dielectric properties.

3) Terminals.

In the United States, with respect to the National Installation codes, equipment operating at more than 600 V is considered high-voltage equipment. In Canada, with respect to the National Installation codes, equipment operating at more than 750 V is considered high-voltage equipment.