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Chassis Ground
Array Grounding
System Neutral Requirements
Utility Side Isolation Transformer Requirements
152315 Rev C
The chassis ground is a copper bus bar in the Main Inverter Enclosure and has
3/8-16" bolts for terminating the AC ground. The ground conductor size depends
on the size of the main circuit breaker.
NEC Table 250.122 (Ninth Edition) requires that the ground conductor be at least
#3 AWG for a 400 A circuit breaker and #6 AWG for a 200 A circuit breaker.
Torque connections to ground bar in the Main Inverter Enclosure as follows:
•
PV100S-208 - 420 in-lbs (47.5 Nm)
•
PV100S-480 - 420 in-lbs (47.5 Nm)
The equipment ground on the PV100S is marked with this symbol:
AC Ground Bar
(TB1) to be used
for the Chassis
Ground
Figure 3-11 Chassis Ground Bar (TB1)
NEC Article 690-41/42 (Ninth Edition) requires the PV array to be earth
grounded. The PV100S chassis is also bonded to the PV safety ground terminal
block.
The PV100S is designed to be installed as a 4-wire system. As required by the
UL 1741 listing, a neutral conductor from the utility-interconnect must be
terminated at TB6 within the AC Interface Enclosure to ensure that the AC
voltage sensing circuit can perform an individual phase voltage (line-to-neutral)
measurement. The function of the neutral connection is to provide a point of
reference for measurement purposes that is essentially at ground potential. No
power will flow through the neutral conductor.
The PV100S is supplied with a custom, high-efficiency, isolation transformer as
part of the AC interface/transformer assembly. The utility side windings of the
isolation transformer are configured Wye and must match the voltage at the utility
Main Inverter Enclosure
Wiring - General
3–13
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