SMA SC 250U - Manual (Page 54)

6 Electrical connection SMA America, LLC
54 DISU_SCUS-IA-IUS111711 Installation Guide
Connecting procedure
2. Position the cable lug or lugs on the busbar.
3. Tighten the screw with a nut in a clockwise direction. For torques refer to the table (see section
6.2 ”Cable requirements”, page 32).
4. Connect all AC cables as illustrated above.
6.5 Connecting protective earth
Refer to section 6.2.1 ”Cable requirements for DC, AC and PE connection”, page 32 for general
requirements for DC, AC and PE connection of the Disconnect Unit.
6.5.1 Additional cable requirements for PE connection
☐ Use the screw terminals or cable lugs to connect the AC cables to the AC breakers as described
in section 6.4.5 ”Connecting AC cables to busbars”, page 51.
☐ The conductor size of the PE connection is depending on the installed over-current protection
device. For determination see National Electrical Code
®
, ANSI/NFPA 70 article 250.122.
☐ The Photovoltaic System Grounding must be installed per the requirements of sections 690.41
through 690.47 of the National Electrical Code
®
, ANSI/NFPA 70 and is the responsibility of
the installer.
1. /05*$&
Oxide layers on contact surfaces after transport and storing of the Disconnect Unit.
Yield loss resulting due to poor electrical conductivity.
• Before connecting the cables, clean the contact surfaces.
• Use only the non-woven abrasive delivered with the Sunny Central.
• Do not clean the surfaces with sandpaper.
• Do not damage the tin coating.
• Do not touch the contact surfaces after they have been cleaned.
/05*$&
The AC outputs are isolated from the enclosure and the system grounding. If required by section
250 of the National Electrical Code
®
, ANSI/NFPA 70, the installer is responsible for this
grounding.