590 Series DC Digital Drive Certification
B-7
Branch Circuit/Short Circuit Protection Requirements
The controller requires branch circuit protection. Branch circuit protection requirements must be in accordance with the latest addition of the National
Electrical Code, NEC/NFPA-70.
UL Recognized Component (JFHR2) semiconductor fuses with current ratings and maximum I
2
t ratings as specified below must be used in the
controller. Refer to the table below for the recommended fuse manufacturer and part number.
Controller Rating Semiconductor Fuses
Ratings Part No. Littelfuse
(HP) (A) (V) (A) I
2
t (A
2
s) (or equivalent*)
20 35 500Vac 40 1,000 L50S 40
40 70 500Vac 80 5,000 L50S 80
60 110 500Vac 125 10,000 L50S 125
80 150 500Vac 175 20,000 L50S 175
100 180 500Vac 175 20,000 L50S 175
150 270 500Vac 300 60,000 L50S 300
* Other UL Recognized Component (JFHR2) semiconductor fuses may be installed
upstream of the controller provided that the voltage, ampere and I
2
t ratings shown
above are not exceeded.
Note:
Semiconductor fuses are acceptable as branch circuit short-circuit protection for
the solid-state motor controllers only.
Table B- 1 Branch Circuit/Short Circuit Protection Requirements
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