358.10 Uses Permitted. ... (B) Corrosion Protection. Ferrous or nonferrous EMT, elbows, couplings, and fittings shall be permitted to be installed in concrete, in direct contact with the earth, or in areas subject to severe corrosive influences where protected by corrosion protection and judged suitable for the condition. (C) Wet Locations. All supports, bolts, straps, screws, and so forth shall be of corrosion-resistant materials or protected against corrosion by corrosion-resistant materials.
358.12 Uses Not Permitted. EMT shall not be used under the following conditions: (1) Where, during installation or afterward, it will be subject to severe physical damage (2) Where protected from corrosion solely by enamel ... (6) Where practicable, dissimilar metals in contact anywhere in the system shall be avoided to eliminate the possibility of galvanic action Exception: Aluminum fittings and enclosures shall be permitted to be used with steel EMT where not subject to severe corrosive influences.
Re: Electrical Metallic Tubing Installed Underground#104680 10/09/0312:09 AM10/09/0312:09 AM
It looks like it may be "lava rock" around those pieces. If so, I have found that lava rock is very corosive, even to galvanized material. I've seen it eat completely through window wells when it was used around the foundation. This may be a location where Suitable for conditions is important.
Re: Electrical Metallic Tubing Installed Underground#104681 10/09/0304:54 AM10/09/0304:54 AM