11.2 Isolation check with a MEGER instrument
If the previous check does not give satisfactory results, it is possible to proceed
as follows:
Disconnect the inverter and proceed as follows, one string at a time:
1. Connect the string to a bipolar DC switch
2. Open the DC switch and connect a wire bridge to the side opposite the
string
3. Close the DC switch
4. Measure the isolation resistance between the bridge and ground by means
of a MEGER, applying a test voltage lower than the maximum system
voltage of the PV modules used. The measured resistance should be higher
than "Minimum allowed PV generator insulation" in "Table 1" in the appendix
5. Open the DC switch and disconnect the string.
Warning: Dangerous voltage exists on both DC input and AC output
wires and connections. For the end-user: Please do NOT touch any
live parts.
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DC SWITCH
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010
M
500V
250V
1000V