Additional External Ac And/Or Dc Disconnect; Wsd (Wired Shutdown); Rcmu; Insulation Monitoring - Fronius Primo GEN24 208-240 Operating Instructions Manual

To ensure compliance with all applicable regulations in your country and to en-
sure optimal reception among all recipients, please follow the recommendations
below:
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Additional ex-
Depending on the installation, an additional external AC and/or DC disconnect
ternal AC and/or may be required if the inverter is installed in a location not easily accessible to
DC disconnect utility or first responders. Contact your local authorities for additional informa-
tion.
WSD (wired The wired shutdown (WSD) interrupts the inverter's grid power feed if the trigger
shutdown) device (switch, e.g., Emergency Stop or fire alarm contact) has been activated.
If an inverter (slave) fails, it is bypassed and the other inverters continue operat-
ing. If a second inverter (slave) or the inverter (master) fails, the operation of the
entire WSD chain is interrupted.
For installation, see

RCMU

The inverter is equipped with an RCMU (RCMU = residual current monitoring
unit) according to UL1741 CRD 3rd Edition (Non-Isolated EPS Interactive PV In-
verters).
It monitors residual currents from the PV module up to the AC output and dis-
connects the inverter from the grid when an improper residual current is detec-
ted.If five faults are detected within a period of 24 hours, grid power feed opera-
tion can also be permanently interrupted until a manual reconnection has been
performed.
Insulation Mon-
In the case of PV systems with ungrounded PV source circuits, the inverter
itoring checks the resistance between the positive or negative pole of the PV system
and the earth potential before feeding energy into the grid. In the event of a
short circuit between the DC+ or DC- cable and ground (e.g. due to inadequately
insulated DC cables or damaged solar modules), the inverter is prevented from
feeding energy into the grid.
AFCI - Arc Fault
An AFCI (arc fault circuit interrupter) protects against arc faults and, in the nar-
Circuit Inter- rower sense, is a protection device in the event of contact errors. The AFCI eval-
rupter (Arc uates faults that occur in the current and voltage flow on the DC side using an
Guard) electronic circuit and shuts down the circuit if a contact error is detected. This
significantly reduces potential overheating and fire risk at poor contact points.
Keep the distance between the DC+ and DC- conductors as small as possible
Avoid cable loops caused by cables that are too long (coil effect)
Use metal cable ducts where possible
Do not place DC cables from different inverters in the same cable duct or
cable tray
Installing the WSD (wired shutdown) on page 66.
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