Connection Types Wiki · Electrical

EMT Conduit Compression Socket

The tubing-receiving end of a raintight EMT compression fitting: a body with an external thread, a compression nut and a sealing gland/ring (often plastic or rubber) that grips plain-end EMT conduit and seals it against rain when tightened.

Illustration of a EMT Conduit Compression Socket
Stands for
EMT = Electrical Metallic Tubing (thin-wall steel conduit); 'raintight' = listed to keep rain out in wet locations.
Gender
female
Connects by
compression
Standards
UL 514B (conduit fittings); ANSI C80.3 (EMT conduit; mating EMT); NEMA FB 1; UL 797 (EMT tube)
Regions
North America

How it connects

Plain EMT slides into the nut and body until it bottoms on the tube stop; tightening the nut squeezes a split ring and sealing gland around the tube, giving mechanical grip, grounding continuity and a raintight seal. No threads on the tube.

Male and female halves

Female socket/hub that receives the male plain-end EMT tube. The other end of a connector is usually a male threaded (NPS straight) hub with locknut; couplings have this socket on both ends.

Usually connects to

  • Plain, unthreaded steel or aluminum EMT conduit of matching trade size (ANSI C80.3 / UL 797)

Common sizes

  • EMT trade sizes 1/2–4 in (metric designators 16–103), with OD about 0.706–4.5 in (17.9–114.3 mm).
  • Example ODs: 1/2 in = 0.706 in (17.93 mm), 3/4 in = 0.922 in, 1 in = 1.163 in, 1-1/4 in = about 1.51 in (38.4 mm).

Where it is used

Commercial/industrial EMT wiring and racewaysResidential exposed conduitOutdoor/wet-location runsEMT entry into boxes/enclosures

Variations

  • Compression-to-male-thread box connector
  • Compression-to-compression coupling
  • Raintight/wet-location type
  • Insulated or uninsulated throat
  • Steel or die-cast zinc
  • 90° connector

How to recognise it

A hex or round compression nut on the end of the fitting, a visible colored (often green/yellow/black) gland or seal inside the nut, and RT or 'raintight' in the part number or marking; bore matches EMT OD.

Often confused with

Confused withHow to tell them apart
standard (concrete-tight) EMT compression fittingNon-raintight types have only a split compression ring, no polymer sealing gland, and are not marked RT/raintight.
EMT set-screw fittingSet-screw type has a screw on the side of the socket instead of a threaded compression nut.
rigid/IMC threadless compression fittingSized for rigid conduit OD (larger than EMT for same trade size) and marked for RMC/IMC.
Rigid/IMC threaded conduit fittingRigid/IMC conduit is threaded (NPT) and thick-walled; EMT ends are unthreaded and grip by compression ring. Rigid conduit is threaded (NPT); EMT compression ends take unthreaded tube.
Plumbing compression fitting (ferrule)Plumbing types use brass/copper ferrules sized to tube OD like 1/2 in copper; EMT fittings are zinc-plated steel/zinc sized by conduit trade size.

Also called

EMT compression fitting/socketRaintight EMT compression connector/couplingRT fitting, such as 650RT/260RTEMT compression glandThin-wall conduit compression connection

Good to know

This is the tubing-gripping end only; the opposite end of a connector is a male straight-thread hub (NPS/conduit thread) with locknut, which is a separate port.

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