16
2.0 Installation
©2002 Xantrex Technology Inc. All Rights Reserved.
P/N 975-0049-01-01 Rev A 10/2002
DC Wiring (continued)
DC Disconnect and Over-current Protection
For safety and compliance with national electrical codes
and regulations, battery over-current protection is
required. Fuses and disconnects must be sized to
protect the wiring in the system and are required to open
before the wire reaches its maximum current carrying
capability.
The National Electrical Code (NEC) requires both over-
current protection and a disconnect switch for
residential and commercial electrical systems.
When sizing the DC disconnect, the expected
continuous load on the unit should be used to
determine the DC current. Efficiency loss through the
unit increase the DC current draw and must be
accounted for. Divide the maximum continuous current
draw by the unit’s efficiency. Add a 25% safety margin to
comply with code requirements.
The term “free air” is defined by the NEC 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.
Some installations may not require conduit or a
disconnect device, although over-current protection is
still required.
To protect the battery wiring in the event of a short-
circuit, the installation should include a class-T, DC fuse
with a disconnect switch in the positive line between the
unit and the batteries. Consult your local electrical
codes for the appropriate size of this DC disconnect
based on the size of the DC cables being used for this
installation. DC disconnect and over-current protection
(fuse) are not provided with the unit.
NOTE: Consult your local
electrical code for
exact DC
disconnect and
over-current
protection
requirements.
See your local
dealer for
obtaining the
correct hardware
for your
installation.