# GFCI Open Ground

**URL:** <https://boards.straightdope.com/t/gfci-open-ground/723702>\
**Category:** Factual Questions\
**Created:** [June 28, 2015, 2:58pm UTC](https://boards.straightdope.com/t/gfci-open-ground/723702 "2015-06-28T14:58:27Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![dauerbach](https://avatars.discourse-cdn.com/v4/letter/d/c2a13f/32.png) [@dauerbach](https://boards.straightdope.com/u/dauerbach)\
**Post date:** [June 29, 2015, 7:28pm UTC](https://boards.straightdope.com/t/gfci-open-ground/723702/21 "2015-06-29T19:28:16Z")

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Interestingly, there is a population of spiders in the lower socket. The light switch and the outdoor plugs were both installed at a later date. The switch is in a screened in porch and rarely gets wet. Not so the outdoor sockets.

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**Author:** ![Habeed](https://avatars.discourse-cdn.com/v4/letter/h/a587f6/32.png) [@Habeed](https://boards.straightdope.com/u/Habeed)\
**Post date:** [June 29, 2015, 8:17pm UTC](https://boards.straightdope.com/t/gfci-open-ground/723702/22 "2015-06-29T20:17:10Z")

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What the GFCI does : it compares to a very precise degree the flow of current through the neutral and the hot AC wire. The 2 must equal. If there’s a tiny leakage of current from the hot AC wire - possibly a dirty socket is enough, or dirty terminals inside the socket itself, to something other than the neutral (such as the grounded case in the socket), that creates a ground fault and trips it.

Or, the circuits performing the measurement are very sensitive and can age, causing false trips because the circuitry is detecting a current difference when there isn’t one.

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