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17
Planning Preparations
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DC Disconnects and Over-Current Devices
The DC circuit from the battery to the inverter/charger must be equipped
with a disconnect and overcurrent protection device. Refer to your
applicable installation code.
Type
This device usually consists of a circuit breaker, a “fused-
disconnect,” or a separate fuse and DC disconnect. Do not confuse AC
circuit breakers with DC circuit breakers. They are not interchangeable.
Rating
The rating of the fuse or breaker must be matched to the size of
cables used in accordance with the applicable installation codes.
Location
The breaker or fuse and disconnect should be located as close
as possible to the battery in the positive cable.
Applicable codes may limit
how far the protection can be from the battery.
DC Grounding
Recreational Vehicles
The inverter/charger DC (chassis) ground terminal
needs to be connected to the vehicle chassis by a minimum No. 8 AWG
copper conductor that is either insulated (green) wire rated 90 °C or bare
copper.
Marine Applications
1
The DC grounding conductor may be one size
smaller than the minimum size conductor required for the DC current
carrying conductors providing the overcurrent protection device in the DC
positive conductor is rated no greater than 135% of the ampacity of the DC
grounding conductor and the conductor is no smaller than 16 AWG.
Table 4
Recommended Fuse Sizes
a
a. Based on National Electrical Code (NEC) require-
ments. The NEC requires that the cables be protected
by a fuse or breaker rated to match the cables’ ampac-
ity at 75 °C.
Model
Minimum Fuse Size (A)
Freedom SW 2012
275
Freedom SW 3012
350
Freedom SW 2024
150
Freedom SW 3024
200
1.Per ABYC A-31.
Freedom SW 3K2K InvChg Install Guide.book Page 17 Wednesday, October 12, 2011 4:40 PM
