Solectria Renewables PVI 10kW Installation And Operation Manual page 12

PVI 10kW / PVI 13kW / PVI 15kW
WARNING: All electrical installations shall be done in accordance with all local electrical
codes and the National Electrical Code, Canadian Electrical Code, ANSI/NFPA 70.
WARNING: The grounded DC photovoltaic connection (typically the negative DC
connection) is bonded to ground within the inverter through the ground fault detection and
interruption circuit (GFDI). The grounded DC connection should not be bonded to ground
at any other point in the system. The ungrounded DC connection (typically the positive
DC connection) must never be grounded at any time.
NOTE: When conduit hubs are used on the AC and DC disconnects in an outdoor or wet
location, rain-tight or wet location hubs that comply with the requirements of "Standard
For Fittings For Conduit and Outlet Boxes", UL514B, are to be used.
AC Wiring
For the 3-phase AC wiring, three conductors are required (one per phase) plus additional
conductors for grounds (see grounding section below). No neutral connection is needed. 90°C copper
conductors must be used. The disconnect terminals are listed for 75
temperature ratings of wire and terminals. Torque terminal screws to 45-50 in-lb. Temperature derates,
voltage drop and other considerations may dictate that larger than minimum wire sizes be used. 2 AWG
is the maximum size conductor that can be landed in the terminals. Verify that any wire size choices
meet local codes.
Inverter AC
Model Voltage
10kW 208VAC
10kW 240VAC
10kW 480VAC
13kW 208VAC
13kW 240VAC
13kW 480VAC
15kW 208VAC
15kW 240VAC
15kW 480VAC
The AC grid impedance value at the connection point should be as low as possible to avoid an
increase of the AC voltage to non-permissible values while the inverter feeds to the grid. Minimizing
wiring impedance also results in higher system efficiency.
EXAMPLE: The impedance is the sum of the electricity grid impedance at building
distribution and all impedance values of conductors and connections.
Single conductor impedance values are:
 Approximately 0.14 Ω for 250 feet (76.2 m) 8 AWG conductor
 Approximately 0.09 Ω for 250 feet (76.2 m) 6 AWG conductor
 Approximately 0.05 Ω for 250 feet (76.2 m) 4 AWG conductor
 Conductor impedance of < 0.09 Ω is recommended.
The total impedance phase to phase of the grid plus the interconnecting AC conductors should be
less than 0.18 Ω. Keep in mind that with larger wires, the AC voltages at the inverter will be closest to
the voltages at the building's circuit panel, allowing for the most reliable inverter operation.
DOCR-060002 rev30
Overcurrent Number of AC
Protection Conductors
40A 3 (1 per phase)
40A 3 (1 per phase)
30A 3 (1 per phase)
50A 3 (1 per phase)
50A 3 (1 per phase)
40A 3 (1 per phase)
60A 3 (1 per phase)
60A 3 (1 per phase)
40A 3 (1 per phase)
Installation and Operation Manual
o
C wire; see NEC 310.10 regarding
Minimum AC Wire
Size
8 AWG, 90°C Cu
8 AWG, 90°C Cu
10 AWG, 90°C Cu
6 AWG, 90°C Cu
6 AWG, 90°C Cu
8 AWG, 90°C Cu
6 AWG, 90°C Cu
6 AWG, 90°C Cu
8 AWG, 90°C Cu
12
Maximum AC Wire
Size
2 AWG, 90°C Cu
2 AWG, 90°C Cu
2 AWG, 90°C Cu
2 AWG, 90°C Cu
2 AWG, 90°C Cu
2 AWG, 90°C Cu
2 AWG, 90°C Cu
2 AWG, 90°C Cu
2 AWG, 90°C Cu
July 7, 2010