Art. 817, co. 2, Cod. Proc. Civ. Provides the burden per the part that intends to contest the potestas iudicandi of the referees of propose the relative exception in the first defense subsequent to the acceptance of the assignment. the espresso of the standard also at the contest. Actions that assume the non -existence of the convention of arbitration not leave doubts on the fact that a similar burden ricada also on chi contexts in root the subsistence of the potestas ludicandi of the referees for lack a clause arbitration. remains, confined to the only scope of art. 806 Cod. proc. civ. the content of the only exception to this rule, having to understand for controversies not arbitrators those the the law as not compromisable, compared to which the derogation general discipline A Proposition of the exception finds justification in the intent of the legislator of attribute to rights unavailable or of the workers (in the hypotheses provided by second paragraph of the regulation) a protection strengthened because it is entrusted to guarantees of the ordinary jurisdiction.