Installation Guide

Installation
900-0144-01-01 Rev B 33
Parallel Stacking (Dual-Stack and Larger)
In parallel stacking, two or more inverters are stacked to create a single, common AC bus as shown in
Figure 29.

The slave outputs are controlled directly by the master and cannot operate independently.

All inverters share a common input (AC source) and run loads on a common output.

Slave inverters can go into Power Save mode when not in use. The master will activate individual slaves
based on load demand. This reduces idle power consumption and improves system efficiency.

Up to ten inverters may be installed in a parallel arrangement. The example on this page shows three
inverters. The wiring diagrams on the next few pages show two.
Figure 30 (see page 34) shows the general wiring of the Radian inverters and the AC system connected
to them. This figure is not a physical representation of the inverters and does not depict the GSLC.
Figure 31 (see page 35) shows the locations of AC and network connections. This figure is a physical
diagram for wiring the GSLC, network components, and external AC devices with each inverter.
Figure 29 Example of Parallel Stacking Arrangement (Three Inverters)
When installing a parallel system, the following rules must be observed.

Parallel stacking requires the system display and a communications manager.

One inverter, and one inverter only, is always the master and is programmed as
Master
in the MATE3 system
display. This is the default setting.

The master must be connected to port 1 of the communications manager. Other inverters must not be
selected as master.

All slave inverters, regardless of number, should be selected as
Slave
during programming.

All overcurrent devices must be sized for 50 Aac or less.

All wiring must be sized for 50 Aac or more.

All output circuit breakers must be sized appropriately for loads and inverter wattage.

The AC input (generator or utility grid) must be a single-phase output at the proper voltage and frequency.

The input/output bypass kit for the GS Load Center cannot be used. See page 10 for more information.
21 kVA
230 Vac
7 kVA
230 Vac
7 kVA
230 Vac
7 kVA
230 Vac