Install Manual

Table Of Contents
Determining the Circuit Breaker Size
Inverters should be protected by circuit breakers. This document describes how to
determine which circuit breaker to use in three phase commercial installations.
Using Transformers in Commercial Three Phase
Inverter Installations
Using transformers in a commercial installation is optional. In most cases a transformer
is used to connect the installation to the medium voltage power grid. The following
figure illustrates a typical transformer and commercial three phase inverter installation
topology.
Figure 43: Typical transformer and commercial three phase inverter installation topology
There are many considerations for selecting the suitable transformer and its associated
current limiting devices such as circuit breakers and fuses. The considerations must
include at least the following:
The transformer should be designed for a typical PV system production profile: high
daytime loads with no loads at night.
The current limiting devices should protect the electrical circuits and the inverters
from the excess current created by an overload, or a short circuit. If a short circuit or
Three Phase System Installation Guide MAN-01-00527-1.4
80 Determining the Circuit Breaker Size