Galvanic corrosion poses a large risk particularly to bimetallic overhead conductors as the phenomenon may potentially degrade the conductors’ structural integrity, electrical performance, and overall service life. Various environmental and operational factors may accelerate the galvanic corrosion development within the conductors which worsen the situation if not properly addressed. This paper focuses on analyzing the impact of galvanic corrosion on the total area of the aluminum strands hence the ampacity of the Aluminum Conductor Composite Core (ACCC/TW) conductors. Using the numerical modeling approach of COMSOL Multi-physics, the galvanic corrosion occurring at the aluminum-carbon fiber core interfaces within ACCC/TW conductors are simulated. The impacts of galvanic corrosion development are observed for both perfect and imperfect interfaces which later demonstrate the existence of 25% and 50% artificial mechanical crack in the fiberglass layer. The simulated results reveal a relationship between increased in mechanical crack and accelerated aluminum strand area loss, with a corresponding reduction in ampacity. For example, after 25 months of exposure to galvanic corrosion, the ACCC/TW with 25% crack would lose 4.6% of aluminium strands which reduce the conductor ampacity by 2.3%. The ampacity reduction is found to be worse at 5.03% for the ACCC/TW with 50% of crack. These simulations reveal that as the extent of cracking increases, the rate of aluminum corrosion increases significantly, directly impacting the conductor’s ampacity.