Fronius Primo GEN24 3.0, Operating Instructions Manual

Page: 87 / 192

The following points regarding cabling must be considered:
- The main contacts of contactors K1 and K2 must be installed between the
Fronius Smart Meter and the residual current circuit breaker of the inverter
and the residual current circuit breaker of the backup power circuits.
- The supply voltage for contactors K1 and K2 is provided by the public grid
and must be connected to phase 1 (L1) after the Fronius Smart Meter and
fused accordingly.
- To ensure residual current circuit breakers function in backup power mode,
the connection between the neutral conductor and the ground conductor
must be established as close as possible to the inverter, but in any case be-
fore the first residual current circuit breaker. An NC contact is used for this
purpose for each of the main contacts of contactors K4 and K5. This ensures
that the ground connection is established as soon as the public grid connec-
tion is no longer available.
- As with contactor K1, the supply voltage for contactors K4 and K5 is
provided via phase 1 (L1) of the public grid.
- An NC contact for the relay K3 interrupts the supply voltage to contactors
K1, K2, K4 and K5. This prevents the ground connection from being immedi-
ately disconnected again when power returns to the public grid and the
backup power network of the inverter from being switched to the public grid.
- The NO contact of relay K3 gives feedback to the inverter on whether the
locking was successfully performed by relay K3.
- Additional inverters or other AC sources can be installed in the backup
power circuit after the main contacts of K1 and K2. The sources are not syn-
chronised to the network of the inverter because this backup power network
has a frequency of 53 Hz.
- A Fronius Smart Meter with current transformer is required (e.g. Fronius
Smart Meter 50kA-3 or Fronius Smart Meter TS 5kA-3).
All-pin separa-
tion cabling vari-
ant, e.g. Italy Circuit Diagram
The Circuit Diagram for the 2-pin double separation with ext. grid and system
protection - e.g. Italy, can be found in the appendix to this document on page
184 .
Backup power circuit and non-backup power circuits
IMPORTANT!
Fronius Smart Meter US-240 must be used for these circuit variants.
The backup power circuits and non-backup power circuits must be fused separ-
ately according to the required safety measures (residual current circuit breaker,
automatic circuit breaker, etc.).
In backup power mode, only the backup power circuits are disconnected from
the grid by contactors K1 and K2; an earth connection is only established for
these circuits. The rest of the home network is not supplied with power in this
case.
87
EN