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Installation Manual
SMA Solar Technology AG
DC-CMB-IA-U15-xx-en
6 Electrical Connection
6.4 Leading the Cables through the Cable Glands with sealing Gasket
Seal insert for cable glands for DC main cables:
Cable glands for the DC main cables are each supplied with two seal inserts for different cable sizes.
Cable diameter for seal insert:
24.0 mm to 38.5 mm. Use mounted seal insert.
17.0 mm to 31.0 mm. Replace seal insert for the seal insert supplied in the scope of delivery.
Procedure:
1. Release the cable gland.
2. When inserting the DC main cables, replace the seal insert with the insert in the scope of delivery if necessary (see
above table).
3. Lead the cable through the swivel nut of the cable gland. Ensure that the thread of the swivel nut is facing upwards.
4. Lead the cable through the seal insert.
5. Insert the seal insert into the cable gland together with the cable.
6. Cut the cable to length.
7. Tighten the cable gland with the appropriate torque:
• Cable gland for DC main cable: 7.5 Nm.
6.5 Connecting the String Cables
SMA Solar Technology AG recommends using bootlace ferrules for connecting the string cables to the fuse holders.
Damage to the Combiner Box due to moisture penetration
•
Moisture can penetrate the Combiner Box through unsealed cable glands.
6.5.1 Cable requirements:
o
PV cable type must be available.
o
Conductor cross-section of the string cable for connection of one string cable to the fuse holders: 4 mm
2
to 6 mm
2
.
Procedure
:
1. Attach the string cables to an external cable support rail.
2. Cut the string cables to length and strip 11 mm off the insulation.
3. If you are using bootlace ferrules, mount the bootlace ferrules and crimp gas-tight.
4. Connect the string cables to the screw terminals of the fuse holders (torque: 2.0 Nm). Ensure correct polarity.
5. Use the provided sealing plugs to seal nonused inserts.
6.6 Connecting the DC Main Cables
6.6.1 Cable Requirements
The Combiner Box comes supplied with busbars for connecting the DC cables with terminal lugs. If you wish to
connect the DC cables directly to the terminals, the appropriate terminals are available as accessories.
Requirements for DC main cables and terminal lugs:
o
Use copper or aluminum cables only.
o
Use only tin-plated copper ring terminal lugs for copper cables or bimetal ring terminal lugs for aluminum cables.
o
The width of the terminal lug contact surface must exceed the diameter of the washers (36 mm).
Requirements for DC main cables for direct connection to terminals which are available as
accessories:
o
Use copper or aluminum cables only.
o
The conductor cross-sections of the DC main cables must be selected correctly.
o
The width of terminal lug must not exceed 45 mm.
