Specifications

6.2 Fuses and Circuit Breakers
6.2.1 Fuses
It is recommended to use fuses and/or circuit breakers on
the supply side as protection in case of component break-
down inside the frequency converter (first fault).
NOTICE
Using fuses and/or circuit breakers on the supply side is
mandatory to ensure compliance with IEC 60364 for CE
or NEC 2009 for UL.
WARNING
Protect personnel and property against the consequence
of component break-down internally in the frequency
converter.
Branch Circuit Protection
To protect the installation against electrical and fire hazard,
all branch circuits in an installation, switch gear, machines
etc., must be protected against short-circuit and over-
current according to national/international regulations.
NOTICE
The recommendations given do not cover branch circuit
protection for UL.
Short-circuit protection
Danfoss recommends using the fuses/circuit breakers
mentioned below to protect service personnel and
property in case of component break-down in the
frequency converter.
6.2.2
Recommendations
WARNING
In case of malfunction, not following the recommen-
dation may result in personnel risk and damage to the
frequency converter and other equipment.
The tables in chapter 6.2.4 Fuse Tables list the
recommended rated current. Recommended fuses are of
the type gG for small to medium power sizes. For larger
powers, aR fuses are recommended. For circuit breakers,
Moeller types are recommended. Other types of circuit
breakers may be used, provided they limit the energy into
the frequency converter to a level equal to or lower than
the Moeller types.
If fuses/circuit breakers according to recommendations are
selected, possible damage on the frequency converter is
mainly limited to damages inside the unit.
For further information see Application Note Fuses and
Circuit Breakers.
6.2.3
CE Compliance
Fuses or circuit breakers are mandatory to comply with IEC
60364. Danfoss recommend using a selection of the
following.
The fuses below are suitable for use on a circuit capable of
delivering 100,000 Arms (symmetrical), 240 V, 480 V, 600 V,
or 690 V depending on the frequency converter voltage
rating. With the proper fusing the frequency converter,
short-circuit current rating (SCCR) is 100,000 Arms.
The following UL listed fuses are suitable:
•
UL248-4 class CC fuses
•
UL248-8 class J fuses
•
UL248-12 class R fuses (RK1)
•
UL248-15 class T fuses
The following max. fuse size and type have been tested:
Electrical Installation Design Guide
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