SMA SSM8-21-BS - Manual (Page 30)

6 Electrical Connection SMA Solar Technology AG
30 SSMxx-21-IA-BS-JP-en-20 Installation Manual
Connecting Aluminum Cables to the Terminals
Upon contact with oxygen, an oxide film forms on aluminum surfaces. This oxide film increases transition resistances. For
this reason, the insulated conductors of the aluminum cables must be cleaned immediately before connecting them. If they
are not to be connected immediately after cleaning, the cable ends need to be greased. SMA Solar Technology AG
recommends connecting the greased insulated conductors to the terminals within eight hours.
Procedure:
1. Strip off the DC main cable insulations by 35 mm.
2. Remove any oxide film from the insulated conductors, e.g. with a sharp knife. Do not use a file, sandpaper or brush.
3. Ensure that no further contamination occurs on the insulated conductors.
4. If you do not connect the insulated conductors within ten minutes after cleaning, grease the insulated conductors.
This prevents the formation of an oxide film.
5. Unscrew the set screw with an Allen key.
7. Fasten the set screw (torque: 32 Nm).
8. Ensure that the DC main cables are securely in place.
6.6 Connecting the Grounding Cable
6.6.1 Connecting the Grounding Cable in the SSMxx21-BS
In order to guarantee the function of the surge arrester, it must be connected to the external grounding.
Cable requirement:
☐ Conductor cross-section: 16 mm
2
to 25 mm
2
Requirement:
The grounding cable must be routed into the Sunny String-Monitor through the cable gland (see Section 6.2, page 23).
Procedure:
1. Strip off the grounding cable insulation by 16 mm.
2. Connect the grounding cable to the screw terminal of the surge arrester (torque: 2.5 Nm).
3. Ensure that the grounding cable is securely in place.
4. Ground the grounding cable in the vicinity of the Sunny String-Monitor, e.g. by means of a grounding electrode.
:$51,1*
Risk of fire if dirty or oxidized aluminum cables are connected
Connecting dirty or oxidized DC main cables reduces the ampacity of the live terminals, thereby increasing the transition
resistances. This can cause components to overheat and catch fire.
• Only connect clean and oxide-free conductors of the aluminum cable.
• Ensure that the conductors are free of iron particles.
• Connect the insulated conductors to the terminals within ten minutes after cleaning.
6. :$51,1*
Risk of fire from contact failure if grease comes into contact with the set screw
Grease on the set screw can result in failure to achieve the prescribed torque. Contact failure and increased
transition resistances are the result.
• Insert the insulated conductors into the terminal from below. Ensure that no grease comes into contact with the
set screw.