SAMLEX AMERICA INC. | 43
SECTION 8 |
Installation
WARNING!
Use of an appropriately sized external fuse as described above is mandatory to provide safety against
fire hazard due to accidental short circuit in the battery cables. Please note that the internal DC side
fuses are designed to protect ther internal components of the inverter against DC side overloading.
These fuses will NOT blow if there is a short circuit along the length of wires connecting the battery
and the inverter.
8.4.5 Recommended Sizes of Battery Cables and Fuses
Sizes of cables and fuses are shown in Table 8.2. Sizing is based on safety considerations specified in NEC-2014.
Please refer to “Notes for Table 8.2” for details.
TABLE 8.2 RECOMMENDED SIZING OF BATTERY CABLES AND EXTERNAL BATTERY SIDE FUSE
Model No.
(1)
Rated DC Input
Current
(See Note 1)
(2)
Minimum
Ampacity of
cable as per NEC
(See Note 2)
(3)
External Battery
Fuse Size (Based
in Column 2)
(See Note 3)
(4)
Minimum cable size
(See Note 4)
3 ft / 0.91M
(5)
6 ft / 1.83M
(6)
10 ft / 3.05M
(7)
PSR-1200-24
80A
100A
80A
AWG#3
AWG#3
AWG#2
PSR-1200-48
40A
50A
40A
AWG#8
AWG#8
AWG#8
NOTES FOR TABLE 8.2
1) Column 2 indicates the Rated DC Input Current drawn from the battery.
2) Column 3 indicates minimum NEC Ampacity for sizing of conductors. NEC Ampacity is not less than 125%
of the rated DC input current (Column 2) - Refer to NEC-2014 (National Electrical Code) - Section 215.2(A)
(1)(a) for Feeder Circuits.
3) Column (4) indicates the size of external fuse in the battery circuit. It is mandatory to install this fuse
within 7” of the battery Positive terminal to protect the battery cables against short circuit. Amp rating
of the fuse is based on the following considerations:
a) Not less than the Rated DC Input Current (Column 2)
b) Closest Standard Ampere Rating of Fuse has been used - Refer to NEC-2014 (National Electrical
Code) - Section 240.6(A)
c) Where Standard Fuse Rating does not match the required Ampacity (Column 2), the next higher Stand-
ard Rating of the fuse may be used - Refer to NEC-2014 (National Electrical Code) - Section 240.4(B)
d) Type of fuse: Fast-acting, Current Limiting, UL Class T (UL Standard 248-15) or equivalent
4) Columns 5 to 7 indicate minimum cable conductor size that is based on the following 2 considerations.
Thicker conductor out of the following 2 considerations has been chosen:
a) As per guidelines in NEC (2014) Table 310.15(B)(16) for allowable Ampacities of Insulated Conductors
running in raceway/conduit. Conductor size is based on:
(i) NEC Ampacity specified at Column 3,
(ii) Copper conductor with temperature rating of 75˚C/167˚F and
(iii) Ambient temperature of 30°C / 86°F
b) Voltage drop across the length of cables limited to 2% of 24 VDC i.e. 0.48 VDC for PSR-1200-24 and
2% of 48Vi.e. 0.96V for PSR-1200-48