Page 34 Copyright CPS America Co., Ltd.
The criterion of fuse selection can be calculated by a standard formula in
order to help the installer or service personnel to select the correct rating of
fuse.
The standard formula for DC Fuse Selection:
Nominal Voltage of fuse must be 600V
DC
Rating and the fuse should be
selected between 1.56 x Isc < I
N
Assume the maximum short circuit current (Isc) of the solar module used is
4.85A. The rating of the selected fuse must have a nominal current greater
than 1.25 times but less than 1.6 times the short circuit current as
1.56 x Isc
< I
N
Calculated by Standard Formula:
A)
4.85A x 1.56 = 7.56A
B)
Implemented the above result within
1.56 x Isc < I
N
C) The calculation result will be 7.56A < I
N
. That means installer must to
select a fuse rating that is greater than 7.56 A, but must lesser than 9.70
A. Refer to the products information provided from Littelfuse factory, we
are able to select KLKD008, 8A, 600V
DC
DC as the protection fuse for
the DC input side.
IMPORTANT
The fuse calculation for the fuse selection is referring to the
requirements (information) that had been indicated within the
National Electrical Code(NEC), ANSI/NFPA 70.
To ensure trouble-free fuse protection, Eaton recommends using
fuses that have been tested by Eaton. The specifications for
fuses from Littelfuse and KLKD series can be downloaded from
It is important to follow the standard formula in order to select the
proper rating of fuse for DC protection. And the size of the DC
and AC wiring must to meet with the required size of cables as
description at chapter H) DC input terminal block and chapter J)
AC output terminal block in the section 6.2.
