Wis. Stat. § 196.32

(1) Any witness who appears before the commission or its agent, by order, shall receive for the applicable attendance the fees provided for witnesses in civil cases in courts of record, which shall be audited and paid by the state in the same manner as other expenses are audited and paid under s. 885.07, upon the presentation of proper vouchers sworn to by such witnesses and approved by the chairperson of the commission. Fees paid under this section shall be charged to the appropriation for the commission under s. 20.155 (1) (g). 34196.32 REGULATION OF PUBLIC UTILITIES (2) No witness subpoenaed at the instance of parties other than the commission may be compensated under this section unless the commission certifies that the testimony of the witness was material to the matter investigated.