Thomas & Betts 677 Erickson Coupling, 1" Trade Size
The Thomas & Betts 677 Erickson Coupling is a 1" trade size conduit fitting designed to join two runs of conduit end-to-end without requiring either section of conduit to be rotated during installation. Known industry-wide as an Erickson-style coupling, this fitting uses a draw-together design so electricians can complete a run even when one or both conduit lengths are fixed in place and cannot be turned. As part of the Thomas & Betts family of conduit fittings, the 677 coupling gives contractors a practical, no-turn connection method for standard 1" conduit systems. This 677 model gives contractors and electricians alike a straightforward option for completing 1" conduit runs without extra hardware or complex installation steps.
Key Features
- Trade Size: 1" coupling sized to match standard 1" conduit runs.
- Erickson-Style, No-Turn Union: Joins two conduit sections together without requiring either piece to be rotated, ideal for confined spaces, fixed runs, or existing installations where turning conduit is not practical.
- Simplified Field Installation: Reduces labor and installation time compared to conventional threaded couplings that require turning the conduit into place.
- Versatile Use: Suited for new conduit runs as well as repair and retrofit work where an existing conduit section must be spliced into a new run.
- Standard Compatibility: Sized for common 1" trade size conduit used throughout commercial and industrial wiring systems.
- Thomas & Betts Build Quality: Manufactured by Thomas & Betts, a long-established supplier of conduit fittings, couplings, and electrical connection hardware for the professional trade.
Technical Specifications
- Refer to manufacturer documentation for complete technical specifications.
Typical Applications
- Conduit and Raceway Systems
- Commercial and Industrial Electrical Installations
- Tight-Space or Fixed Conduit Joints Where Rotation Is Not Possible
- Conduit Repair, Retrofit, and Splice Work
- Renovation and New Construction Wiring Projects
Why Thomas & Betts?
Thomas & Betts is a recognized name in electrical conduit fittings, and the 677 Erickson Coupling reflects that focus on practical, installation-friendly hardware built for the realities of the job site. By eliminating the need to rotate conduit during connection, this 1" coupling helps electrical contractors complete conduit runs efficiently, whether on new construction or when tying into conduit that is already fixed in place. For crews who need a dependable no-turn connection on 1" conduit runs, the Thomas & Betts 677 is a simple, purpose-built choice used on job sites nationwide.
Manufacturer Resources
Product Specs
- Product Type:
- Conduit Coupling
- Department:
- Electrical
- Product Group:
- Conduit & Raceway
- Product Subgroup:
- Conduit Fittings
- Product Material:
- Malleable Iron
Thomas & Betts TB677 – Frequently Asked Questions
1) How do you join two conduit runs when neither end can be rotated?
That is exactly what an Erickson coupling does. The Thomas & Betts Erickson coupling uses a draw-together union, so two conduit sections pull into each other without either length being turned. Standard threaded couplings need one piece spun into the thread, which is impossible when both ends are strapped, boxed, or buried in a tight ceiling. Use the Erickson for repair splices, tie-ins to existing fixed runs, and confined spaces.
2) What trade sizes does the Thomas & Betts Erickson coupling come in?
Two sizes: 1 inch (model 677) and 4 inch (model 684). Order by the trade size of the conduit you are joining, and both ends must be the same size, since this is a straight coupling rather than a reducer.
3) Will an Erickson coupling work on EMT?
No. The Erickson is a threaded union, so it mates to threaded conduit, rigid or IMC, not to plain EMT. For EMT you need a setscrew or compression coupling. If you are tying EMT into a rigid or IMC run, the Bridgeport Fittings 291-RT Mighty-Merge transition coupling handles EMT to IMC/rigid at 3/4 inch.
4) Is a 4 inch Erickson coupling the right way to splice a damaged rigid conduit run in an existing building?
Yes, that is a core use for it. Model 684 covers 4 inch trade size and lets you cut out the damaged section, thread the remaining ends, and draw the new piece in without rotating anything that is already strapped or in a wall. The malleable iron body suits commercial and industrial rigid runs.
5) Is a concretetight rigid coupling an equivalent to the Thomas & Betts 684 Erickson coupling?
They solve different problems. The Thomas & Betts 684 is a 4 inch Erickson-style coupling that draws two fixed conduit ends together so neither length has to be turned. The American Fittings ER concretetight rigid coupling is an electroplated zinc steel rigid coupling rated industrial/specification grade, intended for a concrete-poured rigid run; it is a conventional coupling, so at least one conduit section still has to be rotated into it.
6) Is the Thomas & Betts 684 Erickson coupling steel or zinc die cast?
Malleable iron. That is the usual body material for rigid and IMC conduit unions, and it takes a wrench without cracking the way a die cast fitting can on a 4 inch joint.
7) Can I use an Erickson coupling in a concrete pour?
The Erickson is a field union for splicing fixed runs, and nothing in its data rates it concrete-tight. For a rigid coupling that is, the American Fittings ER concretetight rigid coupling in electroplated zinc steel is the one to pull, and it is specification grade.
8) Do I need any extra parts or sealant to install a Thomas & Betts Erickson coupling?
No added hardware is required. The coupling draws the two threaded conduit ends together on its own, which is why it saves labor over cutting in a conventional threaded coupling. Both conduit ends do need to be properly threaded and reamed before assembly.
9) I need a raintight conduit joint outdoors - does the Thomas & Betts Erickson coupling cover that, or is there a better option?
The Thomas & Betts 677 and 684 Erickson couplings are malleable iron no-turn unions for threaded conduit, chosen for joints where the conduit cannot be rotated. If the deciding factor is a raintight joint, the Bridgeport Fittings 291-RT Mighty-Merge coupling is specified as raintight in die cast zinc at 3/4 inch to 3/4 inch, and the American Fittings ER coupling is a concretetight electroplated zinc steel rigid coupling.
10) Which coupling do I spec on a job that calls for specification-grade rigid fittings?
The American Fittings ER coupling is the one carrying that designation - it is listed as industrial/specification grade, in electroplated zinc steel, and is concretetight. The Thomas & Betts 677 and 684 Erickson couplings are malleable iron and are selected by function instead: they join two threaded conduit runs without rotating either section, which is what you want on a fixed or confined joint.
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Does the Thomas & Betts TB677 come with a warranty?
Absolutely. The Thomas & Betts TB677 is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
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