Stop using a repeatedly tripping unit
Do not bypass protection, substitute a higher-rated breaker or repeatedly restart the unit. Keep away from wet or damaged equipment. If there is smoke, fire or immediate electrical danger, move away and seek emergency assistance.
Keep the useful details
Record the AC model, any displayed error and whether the problem occurs at startup or later. Note whether other appliances were operating and whether one unit or several are affected. Do not remove service panels to obtain more information.
Agree who diagnoses what
An AC specialist may need to assess the equipment while an electrician assesses the supply. Clarify responsibility before booking so the fault is not passed between trades. The proposed remedy should follow diagnosis rather than treating all tripping as a circuit-capacity problem.
Further information
Electrical Safety First: warning signs · E-REDES: faults and network information · Portugal emergency contacts
General safety information, not a diagnosis or a guide to electrical work. UK-specific installation rules are not presented as Portuguese requirements.