Siemens UL 508A Referentiehandleiding - Pagina 14

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Basic steps for calculating the SCCR of a control panel

4.1 SB4.2 – Determining the short-circuit current ratings (SCCR) of individual power circuit components

4.1.2

Basic: Assumed short-circuit current rating

For unmarked components, the assumed maximum short-circuit current rating in accordance

with Table SB4.1 (see extract) can be used for calculating the short-circuit current rating.

Figure 4-2

4.1.3

To increase the short-circuit current rating of a device, an appropriate protective device must

be connected on the line side of it. Which protective device is suitable is stated in the

relevant UL test report of the device whose short-circuit current rating is to be increased.

UL test report

Example: A 3RT2015 contactor has a default value of 5 kA according to its rating plate. The

UL test report states the protective devices with which the short-circuit current rating can be

increased.

Figure 4-3

Table SB4.1: Assumed maximum short-circuit current rating for unmarked components

(extract)

Extract from the UL test report

Short-circuit current rating (SCCR) of industrial control panels

Reference Manual, 06/2013, A5E31896849002A/RS-AA/001