One of the things Sal Mercogliano stressed is that the crew (and possibly other crews of the same line) modified systems in order to save time.

Rather than doing the process of purging high-sulphur fuel that can't be used in USA waters, they had it set so that some of the generators were fed from USA-approved fuel, resulting in redundancy & automatic failover being compromised.

It seems probable that the wire failure would not have caused catastrophic overall loss of power if the generators had been in the normal configuration.