The filing office shall be the office for filing UCC documents relating to all types of collateral except for timber to be cut, as-extracted collateral as set forth in s. 409.102(1) (bg), Stats., and, when the relevant financing statement is filed as a fixture filing, goods which are or are to become fixtures. Regardless of the nature of the collateral, the filing office shall be the office for filing all UCC documents where the debtor is a transmitting utility.
Wis. Admin. Code Department of Financial Institutions DFI-CCS 1.02