# Why do my up-side-down porch light bulbs seem to burn out but still work right-side-up?

**URL:** <https://boards.straightdope.com/t/why-do-my-up-side-down-porch-light-bulbs-seem-to-burn-out-but-still-work-right-side-up/823729>\
**Category:** Factual Questions\
**Created:** [October 30, 2018, 4:02pm UTC](https://boards.straightdope.com/t/why-do-my-up-side-down-porch-light-bulbs-seem-to-burn-out-but-still-work-right-side-up/823729 "2018-10-30T16:02:45Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![lauragale](https://avatars.discourse-cdn.com/v4/letter/l/85f322/32.png) [@lauragale](https://boards.straightdope.com/u/lauragale)\
**Post date:** [October 30, 2018, 4:02pm UTC](https://boards.straightdope.com/t/why-do-my-up-side-down-porch-light-bulbs-seem-to-burn-out-but-still-work-right-side-up/823729/1 "2018-10-30T16:02:45Z")

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Why do my up-side-down porch (yellow, incandescent) light bulbs seem to burn out but still work when I bring them inside and try them on a right-side-up fixture?

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**Author:** ![Ionizer](https://avatars.discourse-cdn.com/v4/letter/i/5daacb/32.png) [@Ionizer](https://boards.straightdope.com/u/Ionizer)\
**Post date:** [October 30, 2018, 4:11pm UTC](https://boards.straightdope.com/t/why-do-my-up-side-down-porch-light-bulbs-seem-to-burn-out-but-still-work-right-side-up/823729/2 "2018-10-30T16:11:55Z")

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Have you looked into the socket to see if it is rusted-out or has lots of dirt/bugs in it? Upside-down outdoor sockets can get ‘weathered’ pretty quick, IME.

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**Author:** ![BwanaBob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bwanabob/32/2985_2.png) [@BwanaBob](https://boards.straightdope.com/u/BwanaBob)\
**Post date:** [October 30, 2018, 4:16pm UTC](https://boards.straightdope.com/t/why-do-my-up-side-down-porch-light-bulbs-seem-to-burn-out-but-still-work-right-side-up/823729/3 "2018-10-30T16:16:51Z")

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Maybe its the filament. If it has separated while upside down the two sides would tend to separate further. Putting it right-side up the two may fall together, allowing electricity to flow.

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**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\
**Post date:** [October 30, 2018, 4:20pm UTC](https://boards.straightdope.com/t/why-do-my-up-side-down-porch-light-bulbs-seem-to-burn-out-but-still-work-right-side-up/823729/4 "2018-10-30T16:20:21Z")

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There’s also the possibility that the filament has broken somewhere but inverting the bulb causes a loose end of it to fall back into place connecting to the rest of the filament. If so, it should completely burn out shortly.

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [October 30, 2018, 4:23pm UTC](https://boards.straightdope.com/t/why-do-my-up-side-down-porch-light-bulbs-seem-to-burn-out-but-still-work-right-side-up/823729/5 "2018-10-30T16:23:13Z")

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My guess would be that the upside-down fixtures are getting a bad connection somewhere.

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**Author:** ![Channing\_Idaho\_Banks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/channing_idaho_banks/32/250_2.png) [@Channing\_Idaho\_Banks](https://boards.straightdope.com/u/Channing_Idaho_Banks)\
**Post date:** [October 30, 2018, 4:35pm UTC](https://boards.straightdope.com/t/why-do-my-up-side-down-porch-light-bulbs-seem-to-burn-out-but-still-work-right-side-up/823729/6 "2018-10-30T16:35:21Z")

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just to be clear, which side of the lightbulb is the up-side and which side is the down-side?