SMA America, LLC
Maintenance
SB50US-80US-IA-en-36
SB50US-80US-IA-en-36
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4. Check the DC varistors (A) for discoloration and visible damage.
• If one of the DC varistors is discolored or damaged, replace all DC varistors:
5. Disconnect the DC varistors:
– Disconnect the string connectors of all ungrounded DC cables from the PV array.
– Remove the four fuse extractors with the string fuses from the fuse holders (B) of the DC
disconnect.
– Remove the four string fuses from the fuse extractors.
– Insert the four fuse extractors without the string fuses into the fuse holders (B) of the DC
disconnect.
6. Ensure that no voltage is present at the DC varistors.
• If no voltage is present, replace all DC varistors:
– Insert the insertion tool into the rectangular
opening of the terminal.
– Remove the DC varistor.
DANGER
Danger to life due to short circuits in the DC varistors
Death or serious injury due to electric shock
• Check whether current is flowing the DC cables.
Tip: Use a current clamp to measure the current.
Only use spare parts from SMA
• Always replace the entire set of DC varistors.
• Order number in Section 12 ”Spare Parts and Accessories” (page 101).
