Sizing The Ground Cable(S); Sizing The Ac Cable - ABB UNO-DM-TL-PLUS-US Product Manual

S
izing the ground cable(s)
ABB inverters must be grounded at the protective earth (PE) connection
point
Size the cable(s) in accordance with NEC and any local codes.
The wire must be large enought to handle the maximum ground fault current that the PV
system might experience.
The warranty is void if the inverter isn't connected to ground through the appropriate termi-
nals.
Follow site wiring diagrams and grounding plans. At a minimum expect
this to include:
- A PV array equipment ground connection
- Inverter prective earth (PE) connection
The Protective Earth (PE) connection point
box, accept 4 wires 8AWG to 4AWG, copper (Torque to 2.0Nm / 1.5 ft-lb).
S
izing the AC cable
The AC output conductors must be sized sized according to operating
temperature range and continuous current ratings.
- Size conductors per NEC Article 310.
- Use 90°C wire only;
- AC wiring terminals
wire size range of 20-6 AWG
Note that undersized wiring may cause nuisance tripping (disconnection)
of the inverter. Too-high wiring impedance increases the AC voltage seen
at the inverter terminals. In compliance with UL1741 and IEEE1547, the
inverter may need to disconnect from the grid under otherwise normal
grid operating conditions: IEEE1547 default settings mandate the inver-
ter operate only if its terminal voltage is in the [+10%/-12%]*Vnom range.
To limit these issues, the system designer must consider the worst case grid
voltage conditions and wiring run lenghts between the inverter to the point of
common connection, and size wiring appropriately. For North America, based
on ANSI B values, the worst case voltage range is +/- 6% of Vnom and line
voltage drop in this case should be limited to less than 3% of Vnom. Lower is
better, so not to dissipate harvested power as heat.
terminal.
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CAUTION
REFER TO LOCAL CODE
FOR WIRE SIZE
ATTENTION
FAIRE RÉFERENCE À LA
LÉGISLATION LOCALE POUR
LA DIMENSION DU CABLE
are spring pressure type and accommodate a
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5 - Installation
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, located inside the wiring
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