©
2015 Sensata Technologies
11
2.0 Installation
2.4.1 DC Wire Sizing
It is important to use the correct sized DC wire to achieve maximum ef
fi
ciency
from the system and to reduce
fi
re hazards associated with overheating. Always
keep your wire runs as short as practical to prevent low voltage shutdowns
and to keep the DC breaker from nuisance tripping (or open fuses) because
of increased current draw. See Table 2-2 to select the minimum DC wire
size (and corresponding overcurrent device) required based on your inverter
model. The cable sizes listed in this table are required in order to reduce
stress on the inverter, minimize voltage drops, increase system ef
fi
ciency, and
ensure the inverter’s ability to surge heavy loads.
If the distance from the inverter to the battery is >5 feet (1.5 m), the DC wire
will need to be increased. Longer cable distances affect the performance of the
inverter. See the lower part of Table 2-2 to determine the minimum DC wire
size needed for various distances greater than 5 feet—based on your inverter
model.
DC Wire Size Exception:
In an OEM RV application, smaller DC wire (with
appropriate overcurrent protection) may be used if the inverter will only be
connected to a dedicated load, and the inverter and dedicated load have
been thoroughly tested and sold together by the OEM as a complete system.
Table 2-2, DC Wire/Overcurrent Device for Rated Use
CSW2012-X
190 amps
229 amps
#8 AWG (8.36 mm²)
#2/0 AWG (67.4 mm²)
[300 amps]
300 amps with time delay
▼
5 to 10 feet =
#4/0 AWG (107 mm²)
10 to 15 feet =
Not recommended
Note 1 - Maximum Continuous Current is based on the inverter’s continuous
power rating at the lowest input voltage with an inefficiency factor.
Note 2 - The grounding conductor for the DC system shall meet the sizing
requirements specified in the NEC for the application, but must be no
smaller than 8 AWG copper. In some applications (i.e., Marine installations),
the DC grounding conductor is required to be no less than one size smaller
than the wire size of the DC positive/negative cables.
Full Load Current
Maximum Continuous Current¹
Minimum DC Ground Wire Size
2
Minimum DC Wire Size
[90
˚
C rating in free air]
Maximum DC Fuse Size
Increased size for
longer distance