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To prevent this please follow Etrel INCH electrical Installation Guide and sticker inside INCH:

3 phase connection:

• correct:
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• wrong (L1 and N switched):
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• wrong (L2 and N switched):
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• wrong (L3 and N switched):
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Please measure between each phase and ground. Results:

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1 phase connection:

• correct:
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•  wrong (switched L1 and N):
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Please measure between phase and ground. Result:

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