Outback Power Systems FLEXmax Extreme Owners Manual - Manual (Page 14)

Installation
12 900-0150-01-00 Rev A
Wiring
This section provides instructions on installing PV array wiring into the charge controller. See page 69 for more
notes on PV array sizing. All wiring must comply with local and national codes.
Grounding
This product is intended to be installed as part of a permanently grounded electrical system. This is shown in the
wiring diagrams in this book. Grounding methods must comply with local and national codes.
The FLEXmax Extreme equipment ground is marked with this symbol:
IMPORTANT:
 Article 690 of the NEC requires ground-fault protection such as the OutBack GFDI.
 It is recommended to bond one of the DC conductors to the ground on the battery
side of the system.
 The DC conductor is connected to the ground as a result of installing the OutBack
GFDI. They should not be bonded separately. If a separate bond is already present
in the system, it should be removed. If present, it will defeat the GFDI protection.
(See page 19.)
 Bonding the negative and ground is most common. However, the FLEXmax
Extreme can be used normally in either negative-ground or positive-ground
systems. Page 14 shows examples of both types of system wiring. See below for
restrictions on positive grounding. Also see page 74.
CAUTION: Equipment Damage
The FLEXmax Extreme can be used in a positive-ground system when networked with
one OutBack inverter. This requires a HUB Communications Manager. (See page 15.)
It cannot be networked in a positive-ground system with multiple inverters. For use of
the FLEXnet DC Battery Monitor or other devices in these applications, see page 74.
Failure to follow these instructions can damage the controller and other devices. This
damage is not covered under warranty.
The following important restrictions apply unless superseded by local or national codes:
 The grounding conductors must be routed separately from all battery conductors.
 The battery conductor (positive or negative) must be bonded to the grounding system at only one point.
Wiring Size and Requirements
IMPORTANT:
Wire sizes must comply with local and national codes. Input conductors and circuit
breakers must be rated at 1.56 times the short-circuit current of the PV array (per NEC).
OutBack 100% duty continuous circuit breakers only need to be rated at 1.25 times the
short-circuit current.
 Please refer to the NEC and other electrical codes for PV array cable sizing, cable length, and cable ampacity.
 Use #4 AWG (25 mm 2 ) wire (minimum) for the output between the FLEXmax Extreme and the battery bus
bar conductors. Smaller cables can reduce performance and possibly damage the unit.
 The output can accept up to #2 AWG (35 mm 2 ) wire. Larger conductors will reduce losses and ensure
highest performance of the FLEXmax Extreme.
 Install properly sized overcurrent protection devices. The required AIC rating of the device is 4000 Adc.