Edison screw threads are the standardized screw bases used in light bulbs and lamp holders worldwide. They are designated with the letter ‘E’, followed by the nominal major diameter in millimeters (e.g., E27 for a 27 mm diameter). These threads provide a secure and reliable electrical connection, ensuring easy installation and removal of bulbs.
Edison screw threads are primarily defined by IEC 60061 and are available in various sizes for different applications, from household lighting (E27, E14) to industrial and specialty uses (E40, E10, etc.).
Key Characteristics:
✔ Thread Profile: Metric screw profile with a rounded crest
✔ Electrical Contact: Designed for electrical connections in lamps
✔ Standardized Sizes: Different diameters for various applications
✔ Common Uses: Incandescent, LED, and CFL light bulbs
✔ Standardization: Defined under IEC 60061, ANSI, and DIN specifications
Key Features of Edison Threads
✔ Easy Installation and Replacement for light bulbs
✔ Reliable Electrical Contact with secure threading
✔ Corrosion-Resistant Coatings (e.g., nickel-plated brass)
✔ Designed for High-Temperature Environments
✔ Standardized Globally for interoperability
Edison Thread Types and Dimensions
The following table provides common Edison thread types and their standard dimensions:
| Designation | Major Diameter (mm) | Pitch (mm) | Typical Application |
|---|---|---|---|
| E5 | 5.00 | 0.50 | Miniature bulbs, indicator lights |
| E10 | 10.00 | 1.00 | Flashlights, instrument panels |
| E12 | 12.00 | 1.25 | Candelabra, decorative lighting |
| E14 | 14.00 | 1.50 | Small household lamps, chandeliers |
| E17 | 17.00 | 1.50 | Intermediate-size bulbs |
| E26 | 26.00 | 3.00 | Standard North American light bulbs |
| E27 | 27.00 | 3.00 | Standard European light bulbs |
| E39 | 39.00 | 4.00 | High-power industrial lighting |
| E40 | 40.00 | 4.00 | Large-scale outdoor lighting |
Common Applications of Edison Threads
- Household Lighting (E27, E14) in standard lamps and fixtures
- Industrial & Street Lighting (E39, E40) for high-wattage applications
- Miniature Bulbs (E5, E10) in indicator and automotive lights
- Decorative and Specialty Lighting (E12, E14) for chandeliers and night lights
Related Thread Standards
- ISO 2901 – General Trapezoidal Thread Specifications
- DIN 103 – German Standard for Trapezoidal Threads
- ANSI B1.5 – Acme Threads (North American equivalent)
Important Notice on Standards Validity
This information is for reference purposes only. Users should consult official sources and updated standards to ensure compliance with current regulations. The validity of standards may change over time, so it is recommended to verify them through recognized engineering and standardization organizations (IEC, ANSI, DIN, etc.).
Check with relevant standardization bodies in your region to confirm whether a specific standard is still valid and applicable. Regulations and industry requirements may vary based on region and application.