I found this junction box in a basement located directly under a street near the U.S. Capitol. It was being removed due to severe corrosion caused by salt water. No, it wasn’t near the oceans edge, but below an area where street salt runoff collected during the winter months of the year. This wasn’t the fault of the equipment manufacturer or the installer, but rather the fault of the property owner who choose not to make the necessary repairs to stop the leaks.

Art. 314, Part III, of the 2005 NEC covers the installation and use of all boxes and conduit bodies used as an outlet, device, junction, or pull box, depending on its use, and handhole enclosures. The requirements in 314.40(A) call for metal boxes, conduit bodies, and fittings to be corrosion resistant or well galvanized, enameled, or otherwise properly coated inside and out to prevent corrosion. A Fine Print Note directs you to 300.6 for limitation in the use of boxes and fittings protected from corrosion solely by enamel.

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