Condenser disconnect on the siding
What's wrong here?
- The EMT fittings are not listed for a wet location
- EMT is not permitted on an exterior wall
- The disconnect is not mounted on the condenser itself
- Nothing. This installation is compliant
Show the answer and the code reference
The answer
The EMT coupling and connector outdoors are dry-location set-screw fittings; fittings in a wet location must be listed for wet locations (raintight compression type).
Correct choice: 1. The EMT fittings are not listed for a wet location
358.42 requires EMT couplings and connectors installed in wet locations to comply with 314.15, and 314.15 requires boxes, conduit bodies, and fittings in wet locations to be listed for use in wet locations and arranged to keep water out. Ordinary set-screw fittings are dry-location fittings: water wicks in at the joint, runs down into the bottom of the disconnect, and rusts the tubing and lugs from the inside. Exterior walls in Minnesota also see freeze-thaw that pries a wet joint apart.
How to fix it
Replace the coupling and connector with raintight compression fittings (gland-type, marked for wet locations), and keep the drop entering the bottom or side of the disconnect through a listed raintight connector or hub.
Code references
NEC 2023 358.42 — Couplings and Connectors
Couplings and connectors used with EMT shall be made up tight. Where buried in masonry or concrete they shall be concrete-tight type, and where installed in wet locations they shall comply with 314.15.
Drills citing 358.42NEC 2023 314.15 — Damp or Wet Locations
In damp or wet locations, boxes, conduit bodies, outlet box hoods, and fittings shall be placed or equipped to prevent moisture from entering or accumulating within them, and those installed in wet locations shall be listed for use in wet locations.
Drills citing 314.15NEC 2023 440.14 — Location
Disconnecting means for air-conditioning or refrigerating equipment shall be located within sight from and readily accessible from the equipment. It is permitted on or within the equipment, but not on panels designed to allow access to the equipment or where it obscures the nameplate.
Drills citing 440.14
2026 NEC:same rule and number. Wet-location EMT couplings and connectors still have to be listed for wet locations. Summaries of the parallel RMC rule (344.42) say 2026 replaced the 314.15 cross-reference with plain 'listed for wet locations' wording; it is unconfirmed whether 358.42 got the same edit, but either way the answer and fix are unchanged. Confidence: low
Minnesota
Minnesota adopted the 2023 NEC as the Minnesota Electrical Code effective July 1, 2023 (Minn. Stat. 326B.35; Minn. Rules 1315.0200) and adopts the NEC without section-by-section amendments. No Minnesota change to 358.42, 314.15, or 440.14 is known. Newer permits may fall under a later NEC edition; see the Minnesota page. The Board of Electricity adopted the 2026 NEC, also without amendment, for permits filed on or after Aug. 17, 2026 (exams moved to the 2026 NEC on Sept. 8, 2026); see the 2026 NEC note on this drill.
How Minnesota adopts the NECWhy the other choices are wrong
- EMT is not permitted on an exterior wall. 358.10 permits EMT in wet locations; the fittings and supports have to suit the location, not the tubing itself.
- The disconnect is not mounted on the condenser itself. 440.14 requires the disconnect to be within sight from and readily accessible from the equipment. It is permitted on or within the unit but not required there, and it may not sit on a panel that gives access to the equipment or hides its nameplate.
- Nothing. This installation is compliant. Standard set-screw couplings and connectors are not listed for wet locations, so rain runs straight into the raceway and the disconnect.