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How I upgraded from NEMA 5-15 to NEMA 6-20 for $66

Mike Hawk

Member
Jan 8, 2019
55
97
Tulsa Oklahoma
Figured I'd document this for anyone else's amusement. A relatively cheap and easy upgrade path (with a few caveats) is to use your existing wiring and simply switch out the breaker to a double pole so it get's both phases of 120v and convert the neutral (white) wire to a hot (black/red) wire.

There are three main caveats for this to work:
1) The outlet you're converting can be the only outlet on the circuit. Otherwise you risk anything 120v plugging in to go POOF and start a potential fire.
2) Your existing wiring is 12 gauge. Most new homes use 12 gauge and 20 amp breakers even though the outlets are only 15 amp.
3) You're breaker box can take the added 120v 16a load.

Luckily for me there was an existing outlet in my garage right by the charge port. Even more lucky was it was a dedicated circuit! I decided to give NEMA 6-20 a shot. I may still upgraded to 48a service as I have a HPWC that was gifted to me. Jury is still out.

Anyhoo on to the process:

Before shot: Great, my 60a sub-panel was already maxed out with breakers, no free slots. Drats:
11783679830188461386.jpg


However there was a way around that. I simply converted one of the full size breakers to a twin.

Here's the parts list I got from Home Depot. Left to right, plus a few glorious 18650s thrown in for good measure:
$9.68 20 Amp 2 Pole Circuit Breaker
$9.97 2-20 Amp Single Pole Tandem Circuit Breaker
$4.97 NEMA 6-20 Outlet
$0.98 NEMA 6-20 Outlet Cover
Not shown: $35 NEMA 6-20 Mobile Adapter

29456170375332468644.jpg


The finished product after ~30 minutes of fiddling around swapping breakers and reconnecting the conductors. I added black electrical tape to the neutral that is now getting an extra 120v going to my Tesla outlet. Finding that neutral on the bus bar was not fun, it took several tries trying to trace it in my rats nets of wires.
00009302118640120452.jpg


All done and ready for the Mobile Charger :D
63283374293622180082.jpg


I consume ~20% of my P3D+ battery daily and it takes ~3-4 hours to recharge back to 80% SoC on my NEMA 6-20. There really isn't much need to go for more amperage TBH for my needs. Only one time so far have I taken my car down to less than 10% and it was back up to 80% within 14 hours.

Hope this helps and cheers!

PS I am not a licensed electrician. Do not follow my advice yada yada yada.
 

Petrlol

Member
Oct 16, 2018
399
537
Ohio
Looks good. Any thoughts of a more industrial 6-20 outlet or do they not have as much concern with heat due to low amperage? Will you be doing a lot of plug / unplugging?
 

Rocky_H

Well-Known Member
Feb 19, 2015
6,001
6,925
Boise, ID
Looks good. Any thoughts of a more industrial 6-20 outlet or do they not have as much concern with heat due to low amperage? Will you be doing a lot of plug / unplugging?
It is much less of an issue because of the lower amperage. Notice how thick the wires are that need to carry 40+ amps? It is difficult to make the right kind of clamping connection that can continue/imitate that thickness at a connection point. But you notice how thin 12 gauge wires are? It's not too hard to make a screw clamp approximate that same amount of connection point, so far less likely to have problems with it.
 

nwdiver

Well-Known Member
Feb 17, 2013
7,640
9,772
United States
Figured I'd document this for anyone else's amusement. A relatively cheap and easy upgrade path (with a few caveats) is to use your existing wiring and simply switch out the breaker to a double pole so it get's both phases of 120v and convert the neutral (white) wire to a hot (black/red) wire.

There are three main caveats for this to work:
1) The outlet you're converting can be the only outlet on the circuit. Otherwise you risk anything 120v plugging in to go POOF and start a potential fire.
2) Your existing wiring is 12 gauge. Most new homes use 12 gauge and 20 amp breakers even though the outlets are only 15 amp.
3) You're breaker box can take the added 120v 16a load.

Luckily for me there was an existing outlet in my garage right by the charge port. Even more lucky was it was a dedicated circuit! I decided to give NEMA 6-20 a shot. I may still upgraded to 48a service as I have a HPWC that was gifted to me. Jury is still out.

Anyhoo on to the process:

Before shot: Great, my 60a sub-panel was already maxed out with breakers, no free slots. Drats:
11783679830188461386.jpg


However there was a way around that. I simply converted one of the full size breakers to a twin.

Here's the parts list I got from Home Depot. Left to right, plus a few glorious 18650s thrown in for good measure:
$9.68 20 Amp 2 Pole Circuit Breaker
$9.97 2-20 Amp Single Pole Tandem Circuit Breaker
$4.97 NEMA 6-20 Outlet
$0.98 NEMA 6-20 Outlet Cover
Not shown: $35 NEMA 6-20 Mobile Adapter

29456170375332468644.jpg


The finished product after ~30 minutes of fiddling around swapping breakers and reconnecting the conductors. I added black electrical tape to the neutral that is now getting an extra 120v going to my Tesla outlet. Finding that neutral on the bus bar was not fun, it took several tries trying to trace it in my rats nets of wires.
00009302118640120452.jpg


All done and ready for the Mobile Charger :D
63283374293622180082.jpg


I consume ~20% of my P3D+ battery daily and it takes ~3-4 hours to recharge back to 80% SoC on my NEMA 6-20. There really isn't much need to go for more amperage TBH for my needs. Only one time so far have I taken my car down to less than 10% and it was back up to 80% within 14 hours.

Hope this helps and cheers!

PS I am not a licensed electrician. Do not follow my advice yada yada yada.


Well done sir!! I'm surprised this isn't more popular. It's by FAR the most cost effective L2 option and 16A @ 240 is more than enough unless you're a full time Uber driver... especially as Superchargers become more plentiful so on the very rare occasion you need a quick boost you can just use that...
 

eprosenx

Active Member
May 30, 2018
2,065
2,484
Beaverton, OR
Figured I'd document this for anyone else's amusement. A relatively cheap and easy upgrade path (with a few caveats) is to use your existing wiring and simply switch out the breaker to a double pole so it get's both phases of 120v and convert the neutral (white) wire to a hot (black/red) wire.

There are three main caveats for this to work:
1) The outlet you're converting can be the only outlet on the circuit. Otherwise you risk anything 120v plugging in to go POOF and start a potential fire.
2) Your existing wiring is 12 gauge. Most new homes use 12 gauge and 20 amp breakers even though the outlets are only 15 amp.
3) You're breaker box can take the added 120v 16a load.

Luckily for me there was an existing outlet in my garage right by the charge port. Even more lucky was it was a dedicated circuit! I decided to give NEMA 6-20 a shot. I may still upgraded to 48a service as I have a HPWC that was gifted to me. Jury is still out.

Anyhoo on to the process:

Before shot: Great, my 60a sub-panel was already maxed out with breakers, no free slots. Drats:
11783679830188461386.jpg


However there was a way around that. I simply converted one of the full size breakers to a twin.

Here's the parts list I got from Home Depot. Left to right, plus a few glorious 18650s thrown in for good measure:
$9.68 20 Amp 2 Pole Circuit Breaker
$9.97 2-20 Amp Single Pole Tandem Circuit Breaker
$4.97 NEMA 6-20 Outlet
$0.98 NEMA 6-20 Outlet Cover
Not shown: $35 NEMA 6-20 Mobile Adapter

29456170375332468644.jpg


The finished product after ~30 minutes of fiddling around swapping breakers and reconnecting the conductors. I added black electrical tape to the neutral that is now getting an extra 120v going to my Tesla outlet. Finding that neutral on the bus bar was not fun, it took several tries trying to trace it in my rats nets of wires.
00009302118640120452.jpg


All done and ready for the Mobile Charger :D
63283374293622180082.jpg


I consume ~20% of my P3D+ battery daily and it takes ~3-4 hours to recharge back to 80% SoC on my NEMA 6-20. There really isn't much need to go for more amperage TBH for my needs. Only one time so far have I taken my car down to less than 10% and it was back up to 80% within 14 hours.

Hope this helps and cheers!

PS I am not a licensed electrician. Do not follow my advice yada yada yada.

Fantastic job and documentation!

A few notes for others that read this:

I presume that breaker slot was rated for tandem use (probably was). Usually will have a notched bus stab.

When moving circuits around to tandems, you must be careful to keep multi wire branch circuits (shared neutral) on opposite phase legs. Otherwise you can overload the shared neutral.

I should also note that most household circuits are 14 gauge, so only capable of a 15a circuit. Garage circuits are often (but not always) 12 gauge (for whatever reason NEC allows 15a receptacles on 20a circuits). Regardless, you can also play this trick on 15 amp circuits too. Just do a 6-15 receptacle instead of 6-20.

*very* nice job!

P.S. That panel is tiny! What gauge wire and circuit breaker feed it? You sure you are not pushing the load calcs on it? :)
 

wws

Member
Aug 11, 2014
911
922
Northern California
If the OP is still out there: One tip on doing this is to wrap the repurposed neutral (white) wire with red tape, on both ends, to indicate its new role. Otherwise, job well done.
 

Rocky_H

Well-Known Member
Feb 19, 2015
6,001
6,925
Boise, ID
If the OP is still out there: One tip on doing this is to wrap the repurposed neutral (white) wire with red tape, on both ends, to indicate its new role. Otherwise, job well done.
I added black electrical tape to the neutral that is now getting an extra 120v going to my Tesla outlet.
Wrong color.
No, it is not the "wrong" color.
Citation from NEC here:

200.7 Use of Insulation of a White or Gray Color or with Three Continuous White or Gray Stripes

(C) Circuits of 50 Volts or More.

The use of insulation that is white or gray or that has three continuous white or gray stripes for other than a grounded conductor for circuits of 50 volts or more shall be permitted only as in (1) and (2).

(1) If part of a cable assembly that has the insulation permanently reidentified to indicate its use as an ungrounded conductor by marking tape, painting, or other effective means at its termination and at each location where the conductor is visible and accessible. Identification shall encircle the insulation and shall be a color other than white, gray, or green. If used for single-pole, 3-way or 4-way switch loops, the reidentified conductor with white or gray insulation or three continuous white or gray stripes shall be used only for the supply to the switch, but not as a return conductor from the switch to the outlet.


The color requirement is only that it be a color "other than white, gray, or green". That may be any of the types of colors that are used on hot wires, which can be red or black or blue or orange or many others.
 

wws

Member
Aug 11, 2014
911
922
Northern California
...The color requirement is only that it be a color "other than white, gray, or green". That may be any of the types of colors that are used on hot wires, which can be red or black or blue or orange or many others.

I'd still use red - since there is already a black wire on the other hot leg of the same circuit.
 
  • Disagree
Reactions: cdswm3

xcat

Member
Aug 26, 2016
101
81
Buffalo Grove IL
Good job. I did something similar by using existing conduit for a single 120V run and adding 2 - 10AWG hots and 1 6AWG ground to create a 240-30amp circuit next to the existing 120. Great when you're handy!
 

MN-MS100D

Member
Dec 10, 2018
101
66
Minnesota
Good job. I did something similar by using existing conduit for a single 120V run and adding 2 - 10AWG hots and 1 6AWG ground to create a 240-30amp circuit next to the existing 120. Great when you're handy!

OK, I'll bite. Why did you use a #6 ground wire? Maybe its a typo.
 

essaunders

Member
Jun 6, 2012
132
37
Nashua NH area
nice thread to pop up. My new Y has stolen my 30A EVSE from my old LEAF - so it may be time to upgrade a dedicated 120V 20a outlet I have. I even had it run with an extra conductor so I really should be able to swap out the 120v outlet for a 14-20. My portable EVSE can plug right in -- or I can plug in an adaptor instead and split it out to 120v... the only trick I've got left if figuring out the panel side of things.
 

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