My (under $600) EV charging system

I recently purchased a 2014 Spark EV which came with a 110V EVSE. I could charge the car from an outlet in my garage at the lower 8A setting, but this was exceptionally slow. The garage circuit already had quite a few loads so using the higher 12A setting often tripped the circuit breaker. I needed a better way to charge my car, and this 220V charging system was the result. I couldn't add another 30A breaker to my electrical panel since it was already maxed out, so I decided to piggy back off the garage dryer circuit (220V, 30A). Unplugging the car charger to plug in the dryer every time we wanted to use it would be too cumbersome and dangerous, not to mention that the dryer receptacle was not designed for so many insertions. To solve those problems I used a switch to control whether the 220V circuit is connected to the car or the dryer.


I don't intend this as a build guide since as will soon become painfully obvious I have little knowledge of house wiring standards or best practice. What I have built isn't necessarily safe and may even be downright dangerous for all I know. (I was too cheap to hire an electrician to do the work properly.) I posted this page in the hope that someone will point out the danger in what I have done and perhaps even suggest changes to reduce that danger.

Parts list
OpenEVSE Kit 50A Deluxe Kit $269.00
J1772 Cable 40A Ultra Flexible, 15 feet $145.00
tax & shipping
$ 463.23
Item# 30211352. Bryant 3025BRN Toggle Switch, Double Pole,
Double Throw, 30A, 120/277V AC. $37.95 + tax & shipping
$  45.21
4Ft Dryer Extension Cord, Female 10-30R 3-Prong
Receptacle & Male 10-30P 3-pin Plug
$  49.95
10/3 Electrical 600V Wire 3 Conductor Flexible cable 30amp
5ft & $1.50 per foot + shipping
$  13.30
Home Depot 032076921262 Ring Terminals, quant 2 ($4.32/each)
$   8.64
Home Depot 785991119046 Steel Switch Box
$   2.43
Home Depot 070686571552 Switch Plate
$   3.23
Total ----------------------------------------


It's crucial to connect the ground of the 3 components (plug, dryer, EVSE) to the correct terminal, but the other two wires are interchangeable.

The colors in parentheses are the switch screw colors.

If your dryer is on the right side of the car (looking into the garage), then you will want to swap the use of the gold and copper screws. Either that or mount the switch upside down from the way I did. (It's easier to remember that the switch paddle points to the powered device).

Switch box assembly

First I cut the extension cord and attached terminals to the ends. (They are not yet crimped in this photo.)

Click any picture on this page to see a larger image. Then click the back button to continue.

These hugely thick wires are probably overkill since my car doesn't draw more than 14A, but since the dryer breaker trip point is 30A I thought it wise to use wiring that can handle that much. However by the time I bent these thick wires around the cable clamp it was kind of a tight fit. Perhaps it would have been easier with a deeper switch box. The black screws (center pole) go to the 220V plug. The copper colored screws (switch in left position when mounted) go to the 220V receptacle for the dryer. The gold color screws (switch in right position) go to the OpenEVSE box using the 5ft 10 gauge cable. Since the switch provides a grounding terminal, I connected that to the switchbox even though the mounting screws already provided a pretty tight connection between the switch body and ground. The grounds are probably the most important connection, so I used a nyloc nut and made sure it was well tightened.

The completed switch box (except for reattaching the sides of the box).

The sides have been reattached. I bought a switchbox with a bracket attached to make it easier to mount.

Originally I was going to mount the switchbox on the wall but then I realized it would be a bit awkward to reach, so I moved it to the cabinet as you can see here.

Unfortunately that meant that the receptacle cable was not long enough to mount it on the wall as planned, so I used some makeshift brackets to mount it to the underside of the cabinet. (A silly place for it.) In retrospect I would have been better off buying a longer dryer extension cord despite the added cost.

Note that I wrapped velcro around the dryer plug. This was not needed to prevent the plug from falling out (since the insertion force is quite high), but I decided to do that to make sure that one couldn't accidentaly stick anything metal in there.

Completed charging system

It has been working great for about 2 years now ... and I haven't electrocuted myself yet :)

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