Installation Guide

Planning
14 900-0160-01-01 Rev B
Generator
These Radian models can work with any “split-phase” generator that delivers reliable AC power
at the appropriate system voltage and frequency. They cannot work with a single-phase or
three-phase generator.

The inverter/charger can provide a start signal to control an automatic start generator. If automatic
generator starting is required, the generator must be an electric-start model with automatic choke. It
should have two-wire start capability. For other configurations, additional equipment may be required.

In any configuration, the inverter may need to be specifically programmed with the system display.
Perform all programming according to the specifications of the generator and the required operation of
the inverter. Parameters to be programmed may include generator size, automatic starting requirements,
and potential fluctuations in generator AC voltage.

A generator that is to be installed in a building usually should not have a bond between the neutral and
ground connections. The generator should only be bonded if there is a specific need. Installations in
North America are expected to bond the neutral and ground at the main electrical panel. See page 29 for
more information on neutral-ground bonding.
Generator Sizing
A generator should be sized to provide enough power for all expected use.

A conservative estimate assumes that both the loads and charging will be maximized at the same time.
However, this can result in an oversized generator with inefficient operation.

A smaller generator may be used for average loads with the inverter’s Support mode providing support
from the batteries during peak loads. The loads can be manually disconnected while charging.

In general, the generator should be sufficiently powerful to handle all necessary load surges.
Other considerations:

Available generator power may be limited by ratings for circuit breakers and/or generator connectors.
The maximum allowed AC circuit breaker size is 50 Aac per Radian inverter/charger.

Many generators may not be able to maintain AC voltage or frequency for long periods of time if they are
loaded more than 80% of rated capacity. This statement may not apply to inverter-based generators,
which typically have more stable voltage and frequency regulation.
Maintenance Bypass Switching
Inverter systems are often equipped with AC maintenance bypass switches or interlocks. If the
inverter system ever needs to be shut down or removed, the AC sources and loads must be
disconnected. A bypass device allows the AC source to deliver power directly to the loads,
bypassing the inverter as shown in Figure 4. This can minimize disruption to the system and avoids
the need for extensive rewiring.
The GS Load Center (GSLC) can be equipped with bypass circuit breakers for this purpose.
However, if multiple Radian inverters are stacked in a single system, then the GSLC bypass kits
should not be used. The bypass function must be simultaneous for all inverters. The GSLC bypass
kits operate independently, not simultaneously.
CAUTION: Equipment Damage
Use of a three-phase generator with this equipment may damage either the inverter or the
generator. This damage to the inverter is not covered by the product warranty.