Power Cord Adapter Inverter (Reverse Converter) Takes two 115 volt outlets and allows you to use 230 volt appliances that uses under 20 amp @ 230 volts (4600 watts) Single phase current to NEMA L6-20R receptacle.  Fast and Easy 220 volts.  

Works with Electric Vehicle Charger EVSE 220-240v Level 2 Car Locking L Nema L6-20P Plug To J1772 EV Charging Station Duosida 20180821

Power supplies for ther 220 to 240 volt receptacles available including but not limited to: NEMA 6-30R, NEMA 6-50R, NEMA 10-30R, NEMA L14-30R, NEMA L16-30R, NEMA 14-60R, and more...

Electrical Outlet Receptacle Tester 3 wire 120 volt  20100823

Answer:  This is incorrect step / understanding.

In order to have the power supply box work, it must be plugged into different phases.

There are two phases of power in every home.

Half of all the outlets are on left phase, and the other half is on right phase.

You must land on one of each phase in order for the power supply to work.

This means if I just randomly select two outlets in a home, I could be plugged into:  two left side phases, 2 right side phases, or 1 of left + 1 right (correct use of power supply, depress phase locator button on the power supply box and will illuminate bright green on the phase locator light if you plugged in correctly.)

If you look at the breaker panel (photo to the right) and notice the column of breakers on the left side and then a column on the ride side.

The way a breaker box is wired is the top left breaker is left phase, the 2^nd from the top left strait down the left column is right phase, 3^rd down is left column is left phase, 4^th down is right phase.  These breakers alternate phase location all the way down each column.

The top right column of breakers works exactly the same way.  You have to land on one left phase and and one right phase to make this item work.  It is OK to have landed on a pair of outlets that is left and right side and each is positioned anywhere in the breaker panel.

Since this power supply box will not work with GFCI or LCI outlets you can also replace a GFCI outlet with a standard wall receptacle.  

Optionally, if the two breakers you want to use are on the same phase, simply change the location of one of the two breakers to be in a different position in the column.   This is very easy to do and only takes a screw driver (see video link below.)  Go outside and turn off the breaker and turn off the breaker that is labeled as ‘main.’  Go back to the garage and take off the garage panel cover.  Grab the breaker you want to relocate and simply switch positions with another breaker either one up or one down in the column.   You can change the location of the breaker or change the location of the wire in the breaker (your choice.)  This will put the breaker on a different phase.  Again, see video below on how to do this.

https://youtu.be/BG9I-PokSdI?si=m06267ZWR54Tiknu

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