Routing wires through masonry wall
Is there a code-compliant way to feed wiring through a masonry wall directly into the back of a surface-mount box, e.g. for a receptacle? The wall in question is stone, and it used to be an exterior wall, but it now separates the house from a sunroom, so I'd say this is a dry location.
I know I could come out of the wall with 1/2" EMT, then elbow into the side of the box. Just wondering if there's a better/easier way. I'd like to minimize the diameter of the hole I have to drill. What about using 3/8" aluminum flex attached to a knockout on the back of the box with one of those connectors that threads into the conduit spiral? Does flex provide enough protection?