Are set screw EMT fittings allowed in wet locations?

No. NEC 358.42 requires EMT fittings in wet locations to comply with 314.15, which calls for wet location listed products. Standard set screw fittings are listed for dry locations only.

Is EMT itself allowed outdoors?

Yes. NEC 358.10(B) permits electrical metallic tubing in wet locations where installed to comply with 300.6 corrosion protection. The restriction is on the fittings, which must be raintight.

How do I know a fitting is raintight?

The fitting or its carton is marked RAINTIGHT or WET LOCATION. Compression style alone is not proof, since some compression fittings are not raintight listed, and concretetight is a separate marking.

Can set screw connectors be used outdoors?

Standard set screw EMT couplings and connectors are dry location products. Outdoors is a wet location by definition, so the answer is no unless the specific fitting carries a raintight marking, and the vast majority of set screw fittings do not.

Where the code says it

Section 358.42 of the 2023 NEC covers couplings and connectors for electrical metallic tubing. They shall be made up tight. Where buried in masonry or concrete, they shall be of the concretetight type, and where installed in wet locations they shall comply with 314.15. Section 314.15 requires enclosures and fittings in damp or wet locations to be installed and equipped so water cannot enter or accumulate, and to be listed for use in wet locations.

Article 100 defines a wet location as installations underground or in concrete slabs in direct contact with earth, in locations subject to saturation with water or other liquids, and unprotected locations exposed to weather. A rooftop, an exterior wall, and a service riser are all wet locations. Section 358.10(B) permits EMT itself in wet locations, so the tubing is not the problem, the fitting is.

What to use instead

Compression fittings marked raintight are the standard answer. The marking is the thing that matters, because there are also compression style fittings that are not raintight listed. Look for RAINTIGHT or WET LOCATION on the fitting or its carton, and remember that a raintight coupling is not automatically a concretetight coupling and the reverse is also true.

Section 300.5(B) requires the interior of enclosures and raceways installed underground to be considered a wet location, which means anything you install on the interior of that raceway system needs conductors listed for wet locations too. That is why THWN-2 is the default rather than plain THHN.

Common field mistakes

The first is mixing fittings on a run that starts inside and passes through the wall. The portion in the wet location, including the fitting at the LB and the fitting into the meter can, must be raintight even though the rest of the run is indoors. The second is using a raintight compression connector but leaving the compression nut hand tight, which does nothing. The third is filling the gap with sealant instead of buying the correct fitting, which does not satisfy a listing requirement under 110.3(B).

Also watch the top of a panel or a disconnect. Section 314.15 and the enclosure type rating in 110.28 both drive you toward a Myers style hub or a raintight fitting with a sealing washer where a raceway enters the top of a Type 3R enclosure, because a plain locknut and bushing lets water track straight down the raceway into the gear.

Field takeaway

Set screw stays inside. Outdoors, on a roof, underground, or anywhere exposed to weather, use compression fittings marked raintight, tighten the compression nut fully, and use a listed hub where a raceway enters the top of a wet location enclosure.