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250V 20A from two NEMA 5-15 outlet Charging different phase?


New Member
Dec 2, 2020
Hi I am new to the EV community and soon gonna pickup my new Tesla model Y. I don't have the outlet other than NEMA 5-15(110V 15A) in my garage, however, there's an other NEMA 5-15 outlet in the next room on different phase (180°). Is that possible to combind them together and put a NEMA 6-20 (240V 20A) outlet on that for faster charging? Like the connector shown in the photo.


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Jan 26, 2019
hartford, ct
that's technically sort of possible, but if those outlets are using 14 gauge wire and/or connected to 15 amp breakers, you'll only be able to use a 6-15, not 6-20. having two circuits allows you to double the voltage, but the amperage is based on wire gauge and breaker rating.
if the outlets are on 15 amp breakers, you can make a 6-15 adapter and charge at 240v/12a (2880 watts). if the outlets are actually rated for 20 amps, then you can use a 6-20 outlet and charge at 240v/16a (3840 watts).

if you're making an adapter, use 12/3 SOOW wire for a 15 amp system or 10/3 SOOW for a 20 amp system.

If you cheat the system and charge at 16 amps via 6-20 on house wiring made for 15 amps, then the breaker will trip every time you charge the car.


Well-Known Member
Feb 19, 2015
Boise, ID
Holy crap! That thing shown in the picture should be thrown in the trash, and you should punch whoever made it.

A few notes on this:
It can't work on GFCI outlets, which all garage outlets have to be, so this is rarely useful.
As @paulk mentioned, if you're using 15A outlets, you have to have a 15A output. You don't get to increase the amps too.

There are a few threads about this on this forum, so do some reading on it. There are ways to do this appropriately and safely, and the device to do it is called Quick220, not that nasty pile of wires you posted the picture of. Here's my comment about it in another thread:

Quick 220 system?


Dec 22, 2019
Those work in a pinch, but should never be used as a permanent solution (the one pictured should not be used at all). If you can get a homeowners permit, running a 240V circuit really isn't that hard and a 6-20 is relatively inexpensive if that's all you need.
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