Basic: Assumed Short-Circuit Current Rating; Basic: Tested Combination Of Devices According To Ul508 - Siemens NEC Article 409 Reference Manual

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

Basic: Tested combination of devices according to UL508

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
14
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