751.02. Determination of temporary custody proceedings; jurisdiction
(1) The following individuals may bring proceedings in the circuit court to determine the temporary or concurrent custody of a minor child:
(a) Any extended family member who has the signed, notarized consent of the child's legal parents; or
(b) Any extended family member who is caring full time for the child in the role of a substitute parent and with whom the child is presently living.
(2) In addition to the requirements of subsection (1), an individual seeking concurrent custody must:
(a) Currently have physical custody of the child and have had physical custody of the child for at least 10 days in any 30-day period within the last 12 months; and
(b) Not have signed, written documentation from a parent which is sufficient to enable the custodian to do all of the things necessary to care for the child which are available to custodians who have an order issued under s. 751.05.