Southwire Components 633SI — 1 in. Steel Set Screw EMT Connector with Insulated Throat
The Southwire Components 633SI is a 1 in. steel set screw type EMT connector designed for fast, reliable connections between electrical metallic tubing (EMT) and outlet boxes, junction boxes, and enclosures. The insulated throat protects wire insulation from abrasion at the point of entry, maintaining conductor integrity and code compliance.
Constructed of steel with a zinc-plated finish for corrosion resistance, the 633SI meets a comprehensive list of industry standards including UL 514B, NEMA/ANSI FB-1, CSA Certified, US Federal Specification A-A-50553, and multiple military specifications (W-F-406D, W-F-406E, W-F-408D, W-S-610D). A single set screw secures the conduit mechanically without the need for tools beyond a standard screwdriver or nut driver, speeding up installation in commercial and industrial applications.
Key Features
- 1 in. trade size for use with 1 in. EMT conduit
- Set screw connection type — fast, secure mechanical engagement
- Insulated throat protects wire insulation from damage at box entry
- Steel construction with zinc-plated finish for corrosion resistance
- UL Listed (File No. E148720) per UL 514B
- CSA Certified and NEMA/ANSI FB-1 compliant
- Meets US Federal Specification A-A-50553
- Meets military specifications W-F-406D, W-F-406E, W-F-408D, W-S-610D
- Sold in boxes of 100
Specifications
| Manufacturer | Southwire Components |
|---|---|
| Manufacturer Part No. | 633SI |
| Trade Size | 1 in. |
| Product Type | Set Screw EMT Connector |
| Connection Type | Set Screw |
| Material | Steel |
| Finish | Zinc Plated |
| Throat | Insulated |
| Standards | UL 514B, UL File No. E148720, NEMA/ANSI FB-1, CSA Certified, A-A-50553 |
| Sold As | Box of 100 |
| UNSPSC | 39121434 |
Applications
Ideal for commercial and industrial electrical installations requiring compliant EMT conduit connections to outlet boxes, junction boxes, pull boxes, and enclosures. The insulated throat version is preferred where wire insulation protection is required by code or specification, including installations governed by NEC Article 358.


