Battery Requirements For Dual Inverter Systems; Table 2-3 Battery Cable To Maximum Breaker/Fuse Size - Xantrex SW Plus 2524 Owner's Manual

Fuse Block (TFB)

Battery Requirements for Dual Inverter Systems

Dual inverters
(not stacked)
976-0043-01-02
inverters to meet NEC/CEC compliance. Two amperage ratings are
available: a DC250 (250 amps) and a DC175 (175 amps) in either single-
or double-pole configurations for single or dual inverter installations.
See "DC Disconnect Boxes (DC175/DC250)" on page 2–24
additional information on the Xantrex DC175 and DC250.
After selecting battery cables based on the distance from the battery bank
to the inverter, add battery overcurrent protection in the battery cable line,
based on Table 2-3. This table will help you to determine your maximum
breaker/fuse size based on the cable size you selected previously.

Table 2-3 Battery Cable to Maximum Breaker/Fuse Size

Rating in
Cable Size Required Conduit
#2/0 (00) AWG 175 Amps
#4/0 (0000) AWG 250 Amps
a. The term "free air" is defined by the NEC/CEC as cabling that is not
enclosed in a conduit or a raceway. Cables enclosed in conduit or
raceways have substantially lower continuous current carrying ability due
to heating factors.
b. The NEC/CEC allows rounding to the next highest standard fuse size
from the cable rating (i.e., 150 amp cable size rounds up to a standard
175 amp size).
Some installations may not require conduit(s) or a disconnect device,
however, overcurrent protection is still required. Xantrex offers a fuse
block (TFBxxx) providing the code-required inverter overcurrent
protection for these applications. These fuses are available in 110, 200,
300 and 400 amp sizes.
Important:
From this point on in this guide, any reference made to a "DC
disconnect" means either a DC breaker or a fuse with a disconnect switch, which
will depend on your specific type of installation.
The success of "stacked" or "dual" inverter systems is dependent on the
quality and maintenance of the DC connections. Stacked inverter sets are
far less forgiving to long, undersized, uneven, and/or poor connections
than are single inverters.
Dual inverter configurations can be used without using the stacking
interface cable. In this configuration, two inverters separately run isolated
loads from the same battery bank or individual battery banks.
Pre-Configuration Planning
Maximum
Rating in
Breaker/Fuse
Size "Free Air"
175 Amps 265 Amps
250 Amps 360 Amps
for
Maximum
Breaker/Fuse
a
Size
b
300 Amps
b
400 Amps
2–15