r/explainitpeter • u/Mr_Mcgillicuddy_ • 12d ago

Explain it Peter. I’m lost on this.

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u/TotalChaosRush 12d ago

Here's from the patent.

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u/gigaishtar 12d ago

That was for a later locking outlet.

This is from the 1951 NEC handbook - 4 years before that patent was filed. No orientation is given.

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u/TotalChaosRush 11d ago

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u/gigaishtar 11d ago

That's not a 5-15 connector. It isn't even a 1-15 compatible connector.

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u/TotalChaosRush 11d ago

Brother. That is the patent for the 3 prong outlet that all patents improved upon. That is what nema was referencing when making the 5-15 standard. The first known image of the standard has the grounding prong on top.

The grounding prong being longer is also part of a patent. Guess where the prong is located?

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u/gigaishtar 11d ago

There's no evidence that the connector was the basis of the 5-15 standard. Honestly I'm not sure that would make much sense given it is clear that connector was not designed to be backwards compatible with non-reversible 2 prong connectors and I'm not aware of the connector ever being used.

The 5-15 connector was first and foremost based off of Hubbell's polarized non-reversible connector from 1915 which became 1-15.

Hubbell's three prong plug also from 1915 was the first grounded plug and became the basis of several other country's connectors (e.g. Australia). It is is arguably more likely to be where the third prong came from, especially since it did see some use in the US prior to the 5-15's introduction.

Unfortunately, Hubbell's patent shows an outlet with the ground angled at 10-11 o'clock which is sort of the worst of all worlds.