Challenge for violation of rules of law relating to the merits of the dispute is admitted only if expressly provided by the parties or by law according to Article 829(3) of the Code of Civil Procedure, and in the absence of such provision in the arbitration clause or arbitration rules, the challenge proves inadmissible.
Challenge for nullity of an arbitral award constitutes a judgment of limited scrutiny, available only for certain specific procedural errors (errores in procedendo) specifically provided by Article 829 of the Code of Civil Procedure, with application of the rule of specificity in formulating grounds in consideration of the rescinding nature of such judgment.
Failure to rule on a request for consolidation of arbitral proceedings does not fall within the nullity defects of the award under Article 829 of the Code of Civil Procedure, it not being possible to scrutinise in challenge proceedings the discretionary exercise of the power to order or not order consolidation of arbitral proceedings.