SMA SC 400HE Installation - Manual (Page 50)

External Connections SMA Solar Technology AG
50 SCxxxHE-IEN104432 Installation Guide
6.1 Connecting High-Current Contacts
The terminals in the DC and AC areas of the Sunny Central are made of copper, so there are no
special requirements for the connection of copper cables. No special measures are required to
connect the DC cable to the cage clamps. The connection of aluminum terminal lugs to the copper
bars of the AC connection or to the fuse holders of LV / HRC 3 fuses in the DC connection area
requires the use of copper-clad aluminum washers. The copper-clad aluminum washers neutralize the
contact resistance between the aluminum terminal lugs and the copper bars. See below for installation
of the copper-clad aluminum washers.
1. Remove any grease from the contacts with a clean cloth and ethanol cleaning solution. Clean
only the contacts used.
2. Clean the contacts with a cleaning felt. The contacts are clean if they have a slight metallic shine.
3. Cleaning creates metal dust. Remove this with a clean cloth and ethanol cleaning solution.
4. Clean copper-clad aluminum washers. Even when cleaning the copper-clad aluminum washers,
copper and aluminum must be strictly kept separate. Only touch the edges of the washers.
5. Insert the copper-clad aluminum washer between the copper and aluminum. For rails, adjust this
copper-clad aluminum washer to the dimensions of the contact areas.
6. Observe the connection sequences and secure the terminal lug.
Keeping the contacts clean
Sweat and fatty acids from the fingers must not be transferred to the contacts. Use clean
gloves to connect the power cabling.
Using different cleaning cloths
The cleaning felt can only be used for one type of material. Never use a felt for aluminum
if it has been used on copper. Store and select the cleaning felt and cloth in a way that
ensures they cannot be mixed up, e.g. by using different colored cloths.
Tin-plated copper is to be treated like copper and tin-plated aluminum like aluminum.
Removing metal dust
Do not remove metal dust with the compressed air gun.