My electrician just installed new wiring in my house. It is of the aluminum wrap type. The roughing in was done and the cable left hanging down in the cellar. It was laid between a water pipe and a painted 80+ year old poured concrete wall. In a period of about 2 months, there is a rotted 5 inch section where the cable was in contact with the pipe. This cable has not been hooked into the service box yet, so no electric has been present in the cable. It looks like severe electrolysis has occurred. How unsafe is this, and what are my options to correct this?
Thanks, Jeff

Electrolysis is exactly what has happened, the act of two dis-similar metals coming in contact with each other. This action dissolves metals.

The electric in the cable is irrelevant if it is on or off. Has no effect or cause on the action.

The only thing that is done to prevent this is to keep the two metals away from each other. If this is not possible and this is the only path the cable can run ,tehn consider using nonmetallic cable like Romex.

The cable does need to be replaced , or at least the damaged section is removed and replaced with a new section of cable spliced in between. And the entire cable must be away from the pipe.

This action of electrolysis is exactly why copper and aluminum wire cannot be spliced together without special connectors and treatment.