Insulation Monitoring; Arc Detector / Interrupter - Fronius Primo 3.8-1 208-240 Instructions De Service

Insulation Moni- The inverter is fitted with the following safety function as required by UL 1741 and the Na-
toring tional Electrical Code:

Insulation monitoring

In photovoltaic systems with ungrounded solar modules, the inverter checks the resistance
between the photovoltaic system's positive or negative pole and the ground potential. In
the case of a short circuit between the DC+ or DC- cable and the ground (e.g., due to poorly
insulated DC cables or faulty solar modules) the inverter disconnects from the grid.
Arc Detector / In- The inverter has an integrated arc detector / interrupter, which detects and deletes serial
terrupter arcs.
A serial arc may occur after the following example errors or situations:
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If an arc is detected, the power is shut down and the grid power feed operation is interrupt-
ed. A status code appears on the display.
The status code on the display must be reset manually before the grid power feed opera-
tion can be resumed.
The power shut down also deletes the serial arc.
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poorly connected DC plug
defective solar module connection sockets
high resistance solder connections between the cells of a solar module
incorrect cable connected to the input terminal of an inverter
defective DC cables that allow a connection to the ground.
NOTE! Power optimizers for solar modules or data transfer via DC cables (PLC
– Power Line Communication) in the PV system can compromise the correct
function of the arc detector / interrupter.
When using such components, it is the responsibility of the system installer to en-
sure that the arc detector / interrupter functions correctly. Contact Fronius Tech-
nical Support for further information.