What's wrong with the aluminum jacket? Is your concern a reaction with the block wall or a damage issue?
I am still curious what your cite is.
I know "damage" is a local call and the local practice varies widely across the country, even from AHJ to AHJ in the same general area. In Md it is common to simply staple Rx on running boards in utility areas. In this area of Florida that is not OK but they will take ENT (smurf). Other areas set the minimum at EMT.
I have not heard about concerns about MC, one way or the other.
[This message has been edited by gfretwell (edited 11-01-2006).]