A challenge for nullity of an award rendered in arbitration under art. 829, co. 1, no. 1, cod. proc. civ. concerns the non-existence or invalidity of the arbitration agreement, a procedural objection which may also be raised by the court of its own motion, whereas any other defect not affecting the existence or validity of the clause or the legal possibility of referring the dispute to arbitration falls within the ground of excess of the limits of the agreement under art. 829, co. 1, no. 4, cod. proc. civ.
A party who did not object during the arbitration that the other parties’ claims exceeded the limits of the arbitration agreement may not challenge the award on that ground, pursuant to art. 817, co. 3, cod. proc. civ.
The objection to the arbitrator’s lack of jurisdiction, save where the clause is null for an inherent defect relating to the non-arbitrability of the dispute, is a strictly procedural objection and is subject to the time limit of art. 817, co. 3, cod. proc. civ. only for the party who took part in the arbitration and not for a party who, having remained absent, contends in the challenge proceedings that the dispute could not be referred to arbitration.