Configuration Of A Load Feeder With 3Rm1 Motor Starter In Compliance With Ul; Function According To Ul 508; Configuration Of Individual Load Feeders - Siemens SIRIUS 3RM1 Manual

The 3RM1 motor starters can be combined with the following fuses for short-circuits
according to type of coordination 2: In a fused configuration with 3RM1 motor starters,
please observe the dimensioning information of the fuse manufacturer.
Table 4- 9 Fuses according to type of coordination 2 for 3RM1 motor starters at 400 V
Motor starter T = 40 °C
A
Article number Rated current [A]
3RM1.01... 0.5
3RM1.02... 2.0
3RM1.07... 7.0
4.6.4

Configuration of a load feeder with 3RM1 motor starter in compliance with UL

4.6.4.1

Function according to UL 508

The 3RM1 motor starters can be combined individually with a circuit breaker (motor starter
protector) or fuses. A group installation is also possible according to UL.
4.6.4.2

Configuration of individual load feeders

A circuit breaker or appropriate fuses is/are assigned to each motor starter.
SCCR short circuit current ratings
The SCCR (short circuit current rating) indicates the maximum permissible short-circuit
current for a switching device. A higher value can only be achieved in combination with
protection devices such as fuses or circuit breakers.
This rating is required for mounting accessories in control cabinets (control panels)
conforming to UL 508a. The switching device or switchgear assembly with the lowest value
specifies the value for the entire control panel.
A low value makes engineering the supply voltage for the control panel difficult.
According to UL 508a, the 3RM1 motor starters have a standard short circuit current rating of
1 kA for the versions up to 2 A rated current and 5 kA for the version with 7 A.
Tests were also carried out with a short circuit rating of 100 kA (high capacity short circuit
current ratings). The UL reports
(https://support.industry.siemens.com/cs/ww/en/view/66427510) include details of possible
combinations with Class J fuses, as well as with a number of circuit breakers.
SIRIUS 3RM1 motor starter
Manual, 06/2016, A5E0345285095020A/RS-AE/005
Short-circuit current Maximum permissible fuse links at 400 V + 10%
operational class gG
Current [kA] Article number
2 FR10GR69V20 (make: Mersen)
2 FR10GR69V20 (make: Mersen)
2 FR10GR69V20 (make: Mersen)
4.6 Load feeders - protection against short circuit
Configuration
Rated current [A]
20
20
20
73