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Ghetto NEMA 6-20 Charging with two 120v 20a outlets

johnmodely

Member
Jan 14, 2020
260
189
NY
So getting my Model Y in a few weeks, and dont have time to do an expensive 30-50A line run from my fuse box to garage for dedicated charger (box is in basement and would require lots of work and wall cutting to run a new line to garage).

I looked around with these crazy expensive 120-240v boxes (like 110-120 and 220-240 Voltage Converters & Accessories over 300 bucks!), so being an electrical engineer I of course came up with the cheapest and simplest solution possible. Figured id share here for other owners.

All you needs is the stuff below


Nema 6-20R(6-20C) 20A 250V Receptacle T-Blade 250Volt Industrial 20A Connector, Easy Assembly 20Amp 250 Volt USA Canada 3-Prong Female Straight Blade Connector, (UL Listed) LK5620R

2x Leviton 515PV 15 Amp, 125 Volt, Grounding Plug, Yellow


Southwire 28828226 12/2 15' NM-B W/G WIRE

So about 30 bucks worth of materials and 30 minutes of your time :D

Now cut your 12 gauge wire in two, and connect the 2 x NEMA 5-15 plugs to one end of both wires, make sure you wire the hot wire (black) so its the right prong as your plugging into wall.


Next take both open ends of the wire and run them to your 6-20 plug, and connect both hot leads to each lead in the connector, and take both ground wires and tie them together in the ground terminal. You can just snip off the neutral lines here since you dont need them (technically you only need 12 gauge wire with two copper lines for this, just couldn't find any).


Thats it, now you got 15 mph charging without touching anything in your house or expensive electrical work for 30 bucks! Keep in mind the two 120v plugs you plug into have to be on different phases (for example my garage plugs and plug right inside the entry hallway are on diffrent phases and about 12 feet apart so this works perfect).



FYI if your risk averse just have your electrician run a line for you...this works but is not to "code". I have 120v 15A outlets on 20A breakers (and lines are 12 gauge), so I'm using my existing plugs instead of changing them out...if you want to be super safe go with a NEMA 6-15 receptacle, which will still offer over twice the charging capacity.
 

frankvb

Supporting Member
Feb 29, 2020
837
517
San Diego, CA
I guess you don't have an electric dryer outlet anywhere close to where the car is? That should at least give you 240V/24A charging.

Did that for a while before I had the dedicated 50A circuit. Cable only had to go through one wall from the laundry area to the garage.
 

johnmodely

Member
Jan 14, 2020
260
189
NY
I guess you don't have an electric dryer outlet anywhere close to where the car is? That should at least give you 240V/24A charging.

Did that for a while before I had the dedicated 50A circuit. Cable only had to go through one wall from the laundry area to the garage.

No dryer outlet is upstairs :/
 

MY-Y

Member
Mar 4, 2020
882
915
MD
I don't endorse this method, and am just pointing out a couple of problems.

1. You have solid NMB wire as a cord. This wire isn't designed to flex (its conductors are solid), nor is the jacket designed for the kind of abuse a cord encounters.
2. If you have a GFCI on either outlet, it will trip.
 

Bad Horse

Member
Aug 10, 2017
162
108
Overland Park
I don't endorse this method, and am just pointing out a couple of problems.

1. You have solid NMB wire as a cord. This wire isn't designed to flex (its conductors are solid), nor is the jacket designed for the kind of abuse a cord encounters.
2. If you have a GFCI on either outlet, it will trip.

Given it's in a garage, per code it should be, but then again I don't endorse OP's plan regardless, so yeah. Literally the protection side of me cringes at even splitting it from two circuits this way.
 

spsheridan

Member
Sep 30, 2019
348
321
Los Angeles
Thats it, now you got 15 mph charging without touching anything in your house or expensive electrical work for 30 bucks! Keep in mind the two 120v plugs you plug into have to be on different phases (for example my garage plugs and plug right inside the entry hallway are on diffrent phases and about 12 feet apart so this works perfect).
Pretty crafty solution there. Many folks won't know what "different phases" mean in your home's electrical system and how to determine when two outlets are on different phases. Maybe you could add a sentence or two giving some guidance on that?
 

wws

Member
Aug 11, 2014
930
949
Northern California
"Safe" commercial versions, such as the Quick 220, incorporate relays to ensure that both plugs are plugged in before energizing the receptacle. Otherwise an unplugged in plug can become a shock hazard. And yeah - use of solid Romex is also bad.

Simplest/safest thing to do in your case would be to convert one of the 120V circuits (assuming it is dedicated to a single receptacle) to 240V. Need to replace the single pole breaker in your panel with a double pole breaker. Move the white wire to the second pole, and wrap with red tape to indicate its new role. On the receptacle end, again wrap white wire with red tape and install a 6-20 receptacle.
 
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johnmodely

Member
Jan 14, 2020
260
189
NY
Pretty crafty solution there. Many folks won't know what "different phases" mean in your home's electrical system and how to determine when two outlets are on different phases. Maybe you could add a sentence or two giving some guidance on that?

You have to look at your breaker panel...each set of outlets should be labeled (ie kitchen outlets, garage outlets etc). The panel should have numbers next to each breaker, which you check on the breaker diagram that should be on the door for which "phase" its on...there should be two wires coming down and dots showing which wire each breaker is connected too. As long as the outlets are on different wires on the breaker your good.
 
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johnmodely

Member
Jan 14, 2020
260
189
NY
"Safe" commercial versions, such as the Quick 220, incorporate relays to ensure that both plugs are plugged in before energizing the receptacle. Otherwise an unplugged in plug can become a shock hazard. And yeah - use of solid Romex is also bad.

Simplest/safest thing to do in your case would be to convert one of the 120V circuits (assuming it is dedicated to a single receptacle) to 240V. Need to replace the single pole breaker in your panel with a double pole breaker. Move the white wire to the second pole, and wrap with red tape to indicate its new role. On the receptacle end, again wrap white wire with red tape and install a 6-20 receptacle.

Right, if there was one outlet that would be the simplest thing to do, unfortunately all the lines in the house are connected to multiple outlets/lights etc so this is not possible.

Like I said this is definitely not to code or the feint of heart...but its a cheap solution that you get for the same thing those 300 dollar parts do.

Also there is no shock hazard if you plug in one first then touch another plug....only the grounds are connected together in the 6-20 receptacle...obviously you shouldn't plug the charger in the receptacle if you haven't plugged in both ends first.
 

user212_nr

Active Member
Aug 26, 2019
1,407
740
US
Also there is no shock hazard if you plug in one first then touch another plug....only the grounds are connected together in the 6-20 receptacle...obviously you shouldn't plug the charger in the receptacle if you haven't plugged in both ends first.

Did you try it?

The phases are connected together inside of the UMC. One one side there is 120v, on the other, a path to ground (you).
 

johnmodely

Member
Jan 14, 2020
260
189
NY
Did you try it?

The phases are connected together inside of the UMC. One one side there is 120v, on the other, a path to ground (you).

Yes I’m talking about with nothing plugged into the receptical . Obviously you should NOT plug in the charger first then plug in the two wall outlets.

If you don’t understand why, you should probably not be making this in the first place.
 

johnmodely

Member
Jan 14, 2020
260
189
NY
it's faint of heart.
if you're not a certified electrician you should not attempt this kludge
if you are a certified electrician you wouldn't do this

Im not a certified electrician, but am an electrical engineer...so I know more about how electricity works than certified electricians, therefore why I am doing this ;)
 

JPoldo

Member
Aug 13, 2017
307
138
Boston, MA
This thread is a hoot. As another crazy EE, I would consider the same ghetto charger, but only for a few days while the permanent 240V receptacle is installed. OP should warn all family members not to touch the temporary charger. And never connect the UMC until both 120v lines are plugged in.

OP should hire an electrician or roll-up his sleeves to run #6-3 wire from basement breaker panel to garage. If not good at wallboard repair & painting, hire a contractor for this portion only.
 
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NR427

New Member
Aug 7, 2017
4
4
Utah
Enjoy the massive voltage drop and equipment damage when just one of your now overloaded circuit breakers trips while charging! I hope you have fresh batteries in your smoke alarms!
 

Electric700

Active Member
May 21, 2013
1,697
361
Florida, United States
So getting my Model Y in a few weeks, and dont have time to do an expensive 30-50A line run from my fuse box to garage for dedicated charger (box is in basement and would require lots of work and wall cutting to run a new line to garage).
...

You could also get a double-pole (240 V) GFCI breaker and install a NEMA 6-20 dedicated outlet. This way you shouldn't have to replace any lines. You may want to get a combination breaker for another circuit and whole house surge protector like the one below:

Search Results for 15 a combo breaker at The Home Depot

Leviton 120-Volt/240-Volt Residential Whole House Surge Protector-R02-51110-SRG - The Home Depot
 

johnmodely

Member
Jan 14, 2020
260
189
NY
Enjoy the massive voltage drop and equipment damage when just one of your now overloaded circuit breakers trips while charging! I hope you have fresh batteries in your smoke alarms!

Both lines rewired to double pole breaker :p
You could also get a double-pole (240 V) GFCI breaker and install a NEMA 6-20 dedicated outlet. This way you shouldn't have to replace any lines. You may want to get a combination breaker for another circuit and whole house surge protector like the one below:

Search Results for 15 a combo breaker at The Home Depot

Leviton 120-Volt/240-Volt Residential Whole House Surge Protector-R02-51110-SRG - The Home Depot

Yes that would obviously be the easy solution of there was a line that went to one or two outlets...unfortunatly all lines in my house feed multiple outlets, lights etc so impossible to "convert" just one line.
 

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