User Documentation
472690250000/03/09.2020
The PV Next String Combiner Box is low-maintenance.
The connections of all DC cables are designed as main-
tenance-free, self-adjusting PUSH IN spring-loaded termi-
nals.
– A visual inspection must be carried out once a year.
– More intensive maintenance and inspection of all com-
ponents must be carried out at least every ve years.
During maintenance work, make sure that no
moisture, dust or foreign objects can penetrate
into the product.
Two procedures are permitted for maintenance
work:
– Working on live components: Only electricians
who are qualied to work on live components
may work under voltage. They must comply
with local regulations (e.g. personal protective
equipment and risk assessment).
– Voltage-free working: Input and output cables
must be properly disconnected and secured
against being switched on again. Voltage-free
work may be carried out by electricians and
trained personnel.
8.1 Annual visual inspection
DANGER
Imminent risk to life!
Up to 1,000 V DC can be present on live parts.
The system must be switched o for this work.
► Switch o the system as described in chap-
ter 2.2.
► Check the String Combiner Box, all PV connectors, ca-
ble glands and cables for damage.
► Check the legibility and xation of the warning symbols
on the enclosure cover. The legibility may be impaired
by weather conditions or UV radiation.
► Check the outer control panel of the switch-disconnector
for damage.
► Check the seal in the enclosure cover. It must be un-
damaged and exible. A porous seal or cracks can lead
to leaks.
► Check the PCB, the fuse holders and all PCB terminals
for damage.
► Check the earthing connection for tight t (observe
torque).
► Check the clamping points on the switch-disconnector
for tight t.
► In the event of damage, contact your Weidmüller repre-
sentative or distributor.
The fuse holders have a silver layer which can
discolour due to oxidation and sulphation. This
discoloration does not constitute a technical de-
fect as it does not aect the electrical properties.
8.2 Checking and replacing fuse links
DANGER
Imminent risk to life!
Fuse links must not be removed or inserted
under load. The system must be switched o
for this work.
► Switch o the system as described in chap-
ter 2.2.
► Before removing a fuse, make sure that
no current is owing through it. Equalising
currents between the string cables can also
lead to life-threatening arcing and cause
damage to the product.
► Ensure that the open circuit voltages of the
string cables are identical before you insert
the fuse links or connect the string cables to
the input terminals. Failure to observe can
lead to dangerous arcing due to equalising
currents.
ATTENTION
The product can be destroyed!
Fuse links with an incorrect surface can damage the
product (e.g. nickel or tin coatings).
► Only use fuse links with silver-plated end caps.
Fuse links must be replaced if they are visibly
damaged or do not pass the continuity test.
For this work you need suitable tools:
– Fuse change pliers or combination pliers
– Multimeter
► Remove the cover from the enclosure.
► Pull the fuse link out of the fuse holder with the tool per-
pendicular to the PCB, without bending the fuse holder.
► Check the fuse holder visually for damage and the cor-
rect seating of the overspring.
► If the fuse link has no visible damage, check it with a
multimeter in the "continuity" setting (resistance meas-
urement).
– Continuous fuse links can be reused.
– Non-continuous fuse links must be replaced.
8 Maintenace