SMA 20000TL Service Manual - Manual (Page 30)

9 Checking the Function of the Surge Arresters
Surge arresters are wearing parts. Their functionality diminishes with age or following repeated
exposure to overvoltage. It is therefore possible for the surge arresters to lose their protective
function over time.
Check the function of the surge arresters as described in the following.
Procedure:
1.
Danger to life due to electric shock
• Disconnect the inverter from all voltage sources (see Section 2.2, page 7).
• Wait 20 minutes before removing the DC protective cover.
2. Release the screws on the DC protective cover
using an Allen key (AF 3), lift the DC protective
cover upwards from below and remove it.
3. Check whether one of the surge arresters is
defective.
If no stripe is visible next to the type designation in the inspection window of the surge arrester,
the surge arrester is in good condition.
If a red stripe is visible next to the type designation in the inspection window of the surge
arrester, the surge arrester is defective.
• Order new surge arresters (see Section 14 "Spare Parts", page 43).
• If new surge arresters are available, replace all surge arresters (see Section 10, page 32
).
9 Checking the Function of the Surge Arresters SMA Solar Technology AG
Service Manual for Installers STP20-25TL-SG-en-11 30