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STRCOM Fused String Combiners
WARNING: Fuses in fused combiner must only be replaced with the same make and
model fuse. KLKD8, KLKD10, KLKD12, KLKD15, KLKD20 or ATM8, ATM10,
ATM12, ATM15 or ATM20. 20A fuses not recommended for use in the 27-30 fuse
position versions.
3 Operation, Tests & Commissioning the PV System
The string combiner is mounted, all connections are made and you are ready to power it up with
the rest of the PV system.
NOTE: Make sure all tools, parts, etc. are removed from the string combiner before
connecting PV strings or uncovering modules.
WARNING: Make a final check for correctness of all AC and DC wiring to the
inverter and in the system. Fuse holders should be open at this point.
NOTE: With the PV modules connected (or uncovered) and inverter disconnects
still off, it is a good final precaution to check PV polarity once more simply by
carefully using a 600V, DC rated digital volt meter and probing the positive (+) and
negative (-) PV connections in the disconnect enclosure.
Checking Individual strings:
Checking Individual strings:
With the PV inverter still off so no current is being drawn from the array through the
combiner, you can check that each string is good by checking the voltage at each fuse
holder on the array side. It is best to open all the fuse holders BEFORE connecting the PV
strings (or uncovering the PV modules).
With all the fuses open, check each string for voltage and polarity by attaching negative
(for a neg. grounded system) lead of a 600VDC rated voltmeter to the negative terminal
block in the combiner and positive (in a pos grounded system) lead to each fuse holder on
the array side.
You should see very slightly different DC voltages from each string (assuming light no
significant shadows are on the array. The polarity should be checked to be correct on all
strings as well.
Close all the fuse holders.
Operation and tests:
Once the string voltages and polarities have all been checked, it is good to check the polarity at the
inverters DC disconnect also for correct polarity, then turn on the inverter.
DOC-020040 rev 4.4
15
Installation and Operation Manual
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