Right now I need a 240 volt outlet in my garage to plug in one of my vintage streetlights. Since it’s 175 watts plus ballast pretty much anything would do for that application.
But I’m going to drywall the garage. And maybe someday electric cars might be practical, so I might as well wire for that. What sort of setup do I need as far as amps and outlet configuration? Are car chargers 240 only or 240/120? What if my sister gets an electric car too? Right now the service to the garage is 60 amps, which 15 years ago I thought was fine for a couple of lights and power tools, but is that going to be an issue now?
Tesla makes a wall-mounted charging unit that can draw 80 amps (@240V). If you really want your garage to be ready for anything, you’ll want to wire it for 240V/100A service. Maybe just run this up to a disconnect mounted on the garage wall; anyone installing a charger can connect to this with conduit on the surface of the drywall.
I may be mistaken but I think Level 2 charge stations have to be hard-wired.
I think the additional current capability of that unit is only usable by Tesla’s cars. The actual battery charger is in the car; the “charging station” just delivers AC power to it and has some logic to communicate status with the vehicle. For example, the car needs to know the cord is attached so it prevents you driving it away, and tells the charge station when it’s done.
One of the problems you’d be facing is exactly where on the car would the charging port be located. Both the Mitsubishi i-Miev and the Nissan Leaf come standard with a J1772 charging port but on the Mitsubishi it’s in the right rear quarter panel and on the Leaf it’s dead center in the nose of the car. You could very well end up wiring an outlet on one side of the garage and then end up kicking yourself because you needed it on the other side.
Most new EVs have a J1772 port which will accept either 220V from a level 2 charger or 110V from a level 1 charger. The port automatically detects the voltage being supplied. In the trunk of the car will be a portable level 1 charger which you can plug in to any 110V outlet but they recommend a GFCI and it will draw 13 amps so you don’t want any other large appliances on that same line. A level 2 charger can be either portable or hard-wired, usually the latter. If it’s portable, you need whatever plug the portable unit requires but if it’s hardwired then there really isn’t any outlet. Basically, you just want 220V wiring as if you were installing a dryer in that location.
FYI, level 2 is a little more than twice as fast as level 1. But the portable level 1 charger has the advantage that it’s really easy to find a 110 outlet just about anywhere.
I have a Tesla and wired a 240V outlet in the garage. I used a 50A breaker and 6-gauge wire. Max continuous current is 40A (code says you can run max 80% of capacity continuously). The outlet is a NEMA 14-50.
I just installed a charger. Sbunny has it pretty much all right. As noted, Level 1 stations run off 120V power and you just need a standard wall jack to plug those in. It takes ~14 hours to charge my car from 0 to 100%. Level 2 run off 240V and take ~3.5 hours. DC Quick Charge stations are newer and not supported by all EVs. These run on 480V and can charge in 30 minutes. Some people are starting to install the Quick Charge stations at home, but they are more for commercial use. IMO it’s not necessary to have it at home - you might need it on the road to quickly charge when in the middle of a trip, but not so much when you’re at home.
Most Level 2 stations usually run at 30-32 amps, so you’ll need a 40 amp breaker for those. Tesla is 40 amp, so 50-amp breaker is needed. There are models that can plug into a socket for indoor use and don’t have to be hardwired. If it’s outside, you need to wire it directly to the circuit box. Here’s one that plugs in from Clipper Creek, which is a popular manufacturer.
First, don’t worry too much which side the car charge port will be on. It’s easy to find a charging station with a 25’ cable. Wire it to someplace fairly central and you’ll be able to reach.
Maybe for now. It seems reasonable to expect that in the future, competing brands may produce electric vehicles with rapid-charge capability that can take full advantage of 100-amp service.
The Nissan Leaf already supports DC Quick Charge as an option. I’ve seen a stat that half of electric cars support it, and that might already be out of date. Unfortunately, there are three different standards that aren’t cross-compatible, but all of them will need 100 A service or more.
That said, I’m not convinced it makes sense for home installation. The times you need a 30-minute charge at home are exceedingly rare for most drivers. The Quick Charge stations are better suited for places like highway rest stops.
Boxes with heavy cut-off switches are cheap enough.
String wires into surface-mounted cut-off switches and worry about which one to run into what plug when the time comes.
When you know what plug, run a line from nearest cut-off to a box with the plug. Run the line through surface-mounted conduit.
For now, just have the wires in place and put up the drywall.
Figure the charging cord will be 25’, which is pretty standard. Most charge ports today are at the front of the car. Stretch a tape measure and see what you get.
You wouldn’t be able to charge both concurrently. Many charge stations and almost all cars allow you to set the charging start time, so if you had two chargers, I guess you could theoretically set one to start after the other was finished. But you’re guaranteed to mess up sometime and blow the circuit, leaving neither car charged.
It’s worth thinking about a future electric car now, but planning for two cars and two charge stations when you don’t even have one EV seems a little premature.
If you really think you’ll get an EV in the next couple years, at least run a 240V cable to a junction box. Then down the road you can install a plug, hardwire a charge station, or run conduit to a different location depending on your needs without cutting into the drywall.
If I put in a 15 amp / 240 outlet now just for my lights, would that be potentially useful for a charger? Or is there nothing between 15 / 120 and 30 / 240 as far as chargers?
240V/15A has, as far as I know, only been used for some window air conditioners. don’t bother; there’s nothing between level 1 (120V/12A) and Level 2 (240V/30A.)
There’s the box and there’s the outlets. You really don’t know (other than that vintage streetlamp) what you’re going to need in outlets. Then there’s the box. If you really want to cover all the bases, go with 240V 100A service, but you might be able to get by with less current. Understand, you can easily snap in a 120v 15A breaker into that, or a 240V 60A breaker. Get the kind with a master on/off lever on the side with the flanges with the holes in them so you can padlock it on or off.
Wire doesn’t care about voltage. It does care about current.
15 A - 14 AWG
20 A - 12 AWG
30 A - 10 AWG
40 A - 8 AWG
60 A - 6 AWG
80 A - 4 AWG
120 A - 2 AWG
With a 20 A breaker and outlet, you can run 30 A wire. DON’T do it the other way around.
Some electric chargers take a 6-30 outlet which would require #10 wire
Others take a 6-50 which would require #6 wire.
Some Tesla specific chargers are even more.
Is something plugged into a 6-30 likely to give me a full charge overnight?
When and if batteries become practical as a primary car, are the charging requirements likely to stay the same?
I had the fun of running #6 wire out to the garage, and I really don’t want to do it again, much less redo the whole service with #2… Which would also require getting an electrician out to upgrade the main house panel…
You’re still thinking in terms of internal combustion cars where you “fill up the tank”.
With an electric car “full charge” is irrelevant. All that matters is if you charge enough overnight to where you can do all your driving the next day.
30A service is 24A continuous. That’s 20% shy of level 2. Depending on the car it gives 15-20 miles of range for every hour you charge. With this you can do the math to tell you if that is enough for the driving you do.
EVs are perfectly practical as a primary car for most people. My EV is my primary car. My only other car is a classic (1971) Corvette that is lucky to see 1,000 miles a year. And I live in Dallas which means a car is needed to go anywhere.