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Komise : IEC/SC 121A (Low-voltage switchgear and controlgear)
K připomínkám do: 18.09.2019
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This document applies to semiconductor controllers and semiconductor contactors for non-motor load intended to be connected to circuits, the rated voltage of which does not exceed 1 000 V AC.

It covers their use:

for operations of changing the state of AC electric circuits between the ON-state and the OFF-state;

with or without bypass switching devices;

as controller, for reducing the amplitude of the RMS AC voltage.

This document does not apply to:

electromechanical contactors (see IEC 60947-4-1);

short-circuit protective device associated with semiconductor controllers and semiconductor contactors (see IEC 60947-4-1 (MPSD), IEC 60947-2 and IEC 60947-3);

semiconductor motor controller or soft-starter equipment (see IEC 60947-4-2);

semiconductor converters (see IEC 60146 series);

all-or-nothing solid-state relays (see IEC 62314);

use of the product within explosive atmospheres (see IEC 60079 series);

software and firmware requirements (see IEC TR 63201[1]);

cyber security aspects (see IEC 63208[2]).

Contactors and control-circuit devices used in semiconductor controllers and contactors are considered compliant with the requirements of their relevant product standard. Where mechanical switching devices are used, they are considered meeting the requirements of their own IEC product standard and the additional requirements of this document. The object of this document is to state as follows:

the characteristics of semiconductor controllers and semiconductor contactors;

the conditions with which semiconductor controllers and semiconductor contactors should comply with reference to:

their operation and behaviour in normal and abnormal operating conditions including overcurrent operating conditions;

their dielectric properties;

the degrees of protection provided by their enclosures, where applicable;

their construction including safety measures against electric shock, fire hazard and mechanical hazard;

the tests intended for confirming that these conditions have been met, and the methods to be adopted for these tests;

the information to be given with the equipment or in the manufacturer's literature.


[1] Under preparation – Stage at the date of circulation: RPUB

[2] Under preparation – Stage at the date of circulation: CD