Device circuit breakers are designed for use in low-voltage switchgear. The DIN EN 60934 standard applies in this case. The standard specifies technical requirements for protective devices, which must be met in order to reliably protect cables and devices. The standard states that device circuit breakers should have a higher rated switching capacity than is required for overload conditions. Together with prescribed short-circuit equipment, they have a conditional rated short-circuit current.
Manufacturers of device circuit breakers offer nominal current strengths from approx. 0.5 A to 16 A with various tripping characteristics. As such, users can precisely tailor their safety equipment to the requirements of their system and therefore ensure maximum availability.
DIN EN 60934 can also be applied to switching devices used for protecting electrical equipment in the event of undervoltage and/or surge voltage. It is applicable to AC voltages up to 440 V and for DC voltages up to 250 V at a rated current of up to 125 A and to switch off rated short-circuit currents of up to 3000 A. This standard contains all of the necessary requirements to ensure/determine adherence to the necessary operating parameters, by means of the type test.
UL 2346 is used as the basis for electronic circuit breakers without electrical isolation.