A UL 2239 EMT one-hole strap is a single-screw fitting used to secure electrical metallic tubing (EMT) to a supporting surface. For selection, match the strap to the EMT trade size, confirm that its material and finish suit the installation environment, and verify the product’s applicable listing and documentation. The strap’s nominal size does not necessarily equal its measured opening, so check the manufacturer’s dimensional information before ordering. This guide explains common sizes, applications, and purchasing checks for B2B buyers.
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This guide is for electrical contractors, distributors, procurement teams, and project engineers sourcing EMT support hardware. It is also useful to importers and OEM buyers comparing product specifications across suppliers. Our focus is on practical product evaluation rather than a substitute for the project’s code review. Requirements can differ by installation conditions, jurisdiction, and project documents.
A one-hole strap is a formed fitting that wraps partly around a conduit and attaches to a surface through one mounting hole. In an EMT installation, it helps hold the tubing in position along a wall, ceiling, or other suitable structure. UL 2239 is a standard associated with hardware for the support of conduit, tubing, and cable; a product description that mentions the standard should be supported by appropriate product marking and documentation. Buyers should verify the exact product and applicable certification rather than relying on a general supplier statement.
The strap provides a mechanical attachment point for the tubing, but the complete installation also depends on the fastener, substrate, support layout, and installation method. A strap should not be treated as a substitute for a fitting that joins conduit sections or protects a conductor entry. Nor does the name “one-hole” by itself establish load capacity, approved use, or compliance. Confirm these details against the product data and project requirements.
EMT is generally identified by nominal trade size, not by its exact outside diameter. The table gives common EMT trade sizes and approximate outside diameters to help with initial product matching. These values describe tubing dimensions, not the strap’s inside profile or opening. Confirm the required strap size and fit with the supplier’s dimensional drawing before placing a production order.
| EMT trade size | Approximate outside diameter | Buyer check |
|---|---|---|
| 1/2 in | 0.706 in (17.9 mm) | Confirm strap designation and formed fit |
| 3/4 in | 0.922 in (23.4 mm) | Check strap opening and tubing compatibility |
| 1 in | 1.163 in (29.5 mm) | Verify mounting-hole and fastener requirements |
| 1-1/4 in | 1.510 in (38.4 mm) | Request a drawing for larger-size fit review |
| 1-1/2 in | 1.740 in (44.2 mm) | Confirm material, finish, and application suitability |
| 2 in | 2.197 in (55.8 mm) | Check availability and packaging for the required quantity |
These are common EMT dimensions, not a complete product range or a guarantee that a particular strap fits every tubing brand. If the job uses a different conduit type, verify its outside diameter and the strap manufacturer’s stated compatibility. Buyers should also distinguish inch trade sizes from measured dimensions when preparing purchase orders. That simple check can prevent mismatched parts and avoidable site delays.
One-hole straps may be offered in different metals and protective finishes, depending on the manufacturer’s range. Coated or galvanized steel is commonly considered for general indoor support applications, while stainless steel may be specified where corrosion resistance is a project concern. Aluminum options may be relevant to certain product or system requirements, but availability and suitability must be confirmed rather than assumed. Select based on the project specification, exposure, compatibility with the supported conduit, and product documentation.
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Finish names alone are not enough to assess suitability. Ask for the exact material and finish description, and clarify whether the strap is intended for indoor, outdoor, damp, or corrosive conditions. Where dissimilar metals are in contact, consult the project requirements and applicable guidance on material compatibility. Do not infer a service life or corrosion rating unless the supplier provides supporting product information.
One-hole straps are used to support EMT along building surfaces where a single attachment point is appropriate for the installation. They can be considered for exposed conduit runs in commercial, industrial, and residential projects, subject to the design and applicable code. The mounting surface and selected screw or anchor must be suitable for the expected installation conditions. For project-specific requirements, follow the engineer’s documents and the locally adopted electrical code.
For example, NEC Article 358.30 includes EMT securing and support provisions, including a general requirement for support within 3 ft (0.9 m) of certain terminations and support intervals not exceeding 10 ft (3.0 m), subject to stated exceptions. Code editions, local amendments, and installation details can affect how a rule applies. Treat those distances as a prompt to check the governing code—not as a complete installation design. The installer or project authority should confirm the requirements for the actual job.
Pricing depends on factors such as size, material, finish, order quantity, packaging, and any requested customization. Minimum order quantity (MOQ) and lead time are supplier- and product-specific, so buyers should request them for the exact configuration rather than relying on a generic estimate. For repeat purchases, provide the same approved drawing or specification with each request to reduce ambiguity. If delivery dates are fixed, ask the supplier to confirm production and shipping schedules in writing.
Before approving a supplier, check whether they can clearly identify the product, provide relevant dimensions, and explain what documentation supports any compliance claim. Ask how they handle samples, specification changes, packaging, and inspection requirements. For custom or private-label sourcing, confirm which details can be customized and what approvals are needed before production. Clear answers at quotation stage help buyers compare offers on a like-for-like basis.
To choose a UL 2239 EMT one-hole strap, first match the strap to the EMT trade size, then verify fit, material, finish, mounting details, and product-specific compliance documentation. The tubing dimensions in this guide are useful for preliminary screening, but the supplier’s drawing and project requirements should determine the final selection. Check installation spacing and fastening requirements against the current locally adopted code and the project documents. These steps give procurement teams a practical basis for evaluating options before ordering.
At SIOSAN, we support B2B inquiries for conduit fittings and related sourcing requirements. Send us the EMT size, required material and finish, applicable documentation needs, quantity, packaging, and destination market so we can review the requested specification and provide a suitable quotation. If you have a drawing or project standard, include it with your inquiry to make product evaluation more precise.
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