I have a screw thread lightbulb where the thread is 11.5 mm across - would that be likely to be E11 or E12? Or something else? Thanks.


The E26 and E27 are usually interchangeable, as are the E39 and E40, because there is only a 1 mm difference in thread outside diameter. E11 and E12 are not interchangeable.

The E11 base is sometimes used for 50/75/100-watt halogen lights in North America, where it is called the "mini-can", and tighter threads are used to keep them out of E12-base nightlights and other places where they could start a fire.[citation needed]

Thank you, Wikipedia.

So E11 is a thing, it is used for high intensity halogens. That bulb is a common night light or festoon (Christmas style string) light, so it will be E12.

| improve this answer | |

Presumably E12 since it rounds to 12 mm and E12 is a more common size. See this: https://www.12vmonster.com/blogs/product-questions/edison-screw-types

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.