4.8.4
Branch circuit protection
WARNING
Risk of electric shock and fire from a network with an excessively high impedance
Excessively low short-circuit currents can lead to the protective devices not tripping or tripping
too late, and so causing electric shock or a fire.
● In the case of a conductor-conductor or conductor-ground short-circuit, ensure that the
short-circuit current at the point where the inverter is connected to the line supply at least
meets the minimum requirements for the response of the protective device used.
● You must use an additional residual-current device (RCD) if a conductor-ground short
circuit does not reach the short-circuit current required for the protective device to respond.
The required short-circuit current can be too low, especially for TT systems.
WARNING
Risk of electric shock and fire from a network with an impedance that is too low.
Excessively high short-circuit currents can lead to the protective devices not being able to
interrupt these short-circuit currents and being destroyed, and so causing electric shock or a
fire.
● Ensure that the uninfluenced short-circuit current at the line terminal of the inverter does
not exceed the breaking capacity (SCCR or Icc) of the protective device used.
Table 4-6
Branch circuit protection according to the IEC standard and UL standard
Frame size Rated power
Article number
Inverter
Fuse according to
the IEC standard
Max. rated current
of the fuse accord‐
ing to UL standard,
Class J
1)
FSAA
0.55 kW
0.75 kW
1.1 kW
1.5 kW
2.2 kW
6SL3210‑1KE11‑8…
6SL3210‑1KE12‑3…
6SL3210‑1KE13‑2…
6SL3210‑1KE14‑3…
6SL3210‑1KE15‑8…
3NA3803
10 A
FSA
3 kW
4 kW
6SL3210‑1KE17‑5…
6SL3210‑1KE18‑8…
3NA3805
15 A
FSB
5.5 kW
7.5 kW
6SL3210‑1KE21‑3…
6SL3210‑1KE21‑7…
3NA3812
35 A
FSC
11 kW
15 kW
18.5 kW
6SL3210‑1KE22‑6…
6SL3210‑1KE23‑2…
6SL3210‑1KE23‑8…
3NA3822
60 A
FSD
22 kW
6SL3210‑1KE24‑4…
3NA3824
70 A
30 kW
6SL3210‑1KE26‑0…
3NA3830
90 A
37 kW
6SL3210‑1KE27‑0…
3NA3830
100 A
45 kW
6SL3210‑1KE28‑4…
3NA3832
125 A
Installing
4.8 Connect the line supply, motor and braking resistor
SINAMICS G120C converter
Operating Instructions, 09/2017, FW V4.7 SP9, A5E34263257B AF
75
