What's the draw from the charger (Amperes)? Does your charger require 120 volts (also)? I'm considering something similar, and was told by the electric guy at HD that these chargers don't need 120 volts, so you would only need 2-conductor (+ ground), but I don't have my charger yet, so I don't know its specs. Also (I didn't read carefully enough), are you putting the charger and the dryer on the same circuit? If so, are you planning to run them simultaneously? (I believe the code would require that you have enough capacity to do so).

It says "32/32 a" on the Tesla app while charging. Makes me wonder if the amperage is capped at 32 for home charging? I don't know if the car is smart enough to recognize that it is being charged via 10 gauge wiring and reduced the amperage.

Charger can handle both 120 volts or 220/240)volts. 2 conductor wire is 120 volts, which would be pretty slow charging. Think 5 miles of charge per hour, tops. Additionally, it a couple hours for the wire to warm up enough to hit that rate if it is cold out. If you do a 3 conductor wire + ground (220/240v), you will be able to charge at a rate of about 30 miles/hour. Big difference between getting a full charge with ease overnight vs. a recovery of maybe 40-60 miles.

Worthy, I don't see anything recommending 60 amps? Regardless, you pointed me in the right direction.

This was the setup the electrician had me ready for: https://www.tesla.com/sites/default/files/pdfs/installation-guides/NEMA_14-30_installation_guide_NA_US_2017.pdf

Shows 10 gauge wiring and all. Really is more of a way to utilizing a dryer outlet than a true EV charging.

This is what I am converting to:

https://www.tesla.com/sites/default/files/pdfs/installation-guides/NEMA_14-50_installation_guide_NA_US_2017.pdf

Guess I am on the hook for replacing the 10 gauge wiring with 6 gauge as I was not specific enough. Thanks for your help!

The first one was for a 30-amp charger. It used 10/3 since it called for a 4-wire installation, which is 240/120vac.

The second is for a 50-amp charger. It uses 6/3, once again for 240/120ac.

These are two different plugs. The charger you purchase should come with one plug or the other depending on the amperage you get.

Is yours for a Tesla? I'm asking because the high-current chargers are different for different makes. I think the 30/240 one is what's called the Level 2 charger, and most (if not all) makes can use that. And I guess the HD guy was wrong; I would need 10/3 + ground for the level 2 charger I want to install. I need to run the line about 100 feet from my house to a convenient charging location.

mtvhike - Yes it is. My beef is that 10/3 30 amp really is designed for dryers. EVs can accommodate dryer plugs as some already have it ready in their home. IMO it never was meant to be the standard install today. Unfortunately, my electrician handled it that way.

I had to replace the outlet with a NEMA 14/50 and switched out breaker for 2 pole 50 amp.

I haven't read the rest of the comments BUT DON'T USE THE CIRCUIT!!!

What you did is extremely dangerous!

The wire will overheat if it's drawing 50A. 10 gauge is only meant for up to 30A.

Whether the electrician did anything wrong depends on what you told him to install.

If all you said is:

"220 volt electrical car charging station in garage"

Then that isn't enough information. He shouldn't have installed anything until he clarified what you wanted.

What exactly did you ask him for?

Hey Greg, I agree with you. I tested and observed it, there was a power draw equivalent to 32 amps, so I think I am OK for a little bit I do plan on having it replaced first chance I get and am in touch with an electrician.

My home builder said all his homes come ready with car charging in garage. What I quoted was a direct take from the building specs. Guess the electrician worked with the goal of satisfying the builder, not the homeowner?

With constant draws, you are only supposed to use up to 80% of the capacity of the circuit.

So the 10 gauge is supposed to be on a 30A breaker, but you should only be drawing up to 24A.

You are drawing 32A (at that moment that you tested it. It doesn't guarantee that is what it's always drawing.)

Yes, there is a safety factor calculated into these values, but it's not a good idea to throw those safety factors away.

My home builder said all his homes come ready with car charging in garage. What I quoted was a direct take from the building specs.

So you didn't ask for the car charging. The builder just told you he'd be supplying a car charger circuit?

Then it isn't the electrician's fault at all. Or even the builder. He gave you what he told you he was giving you. You were supplied with a car charging circuit, it just isn't as good as the car charging circuit that you wanted.

Just like those ads where if you buy a living room couch and love seat set and they'll throw in a free TV. You can't expect that the TV is a top of the line Sony big flat screen. It could be a no-name 13 inch CRT, if you weren't told any differently.

I don't see anything recommending 60 amps?

It was in the Tesla link in my post.

In any case, it's a timely reminder for my upcoming build. But with that kind of potential draw, I may be looking at a 400 AMP service.

And cars are moving to be capable of faster charging of their larger batteries.

Some thoughts here. These are as I understand things, information picked up here and there, so please correct me if I miss on something.

The box that mounts on your garage wall is not a charger. The charger is in the EV. The box is EVSE (Electric Vehicle Service Equipment). Basically it's a fancy extension cord and plug converter with some added computer smarts.

The EVSE does several things (not necessarily in this order). When you connect it to the EV, it confirms that the connection has been made properly. The EV "talks" to it, saying "Hi, I need a charge, what can you give me?" The EVSE tells the EV how much power (how many Watts) it can supply.

I suppose the EV could theoretically tell the EVSE "No thanks, that's not enough," but in practice it will limit itself to what the EVSE can provide.

The EVSE tests for ground faults. If the connection is correct, there are no ground faults, and the EV and EVSE have agreed on the amount of power to be supplied, the EVSE turns on the electricity and charging begins.

This is a kind of roundabout way of saying that if you have a circuit capable of supplying 30 amps at 240 volts, you can install an EVSE rated to deliver up to 5760 Watts (240 * 30 * 0.8). If your EV has a 40kWh battery, at that rate you can charge it from 0% to 80% in about 5.5 hours (the final 20% of the charge will go slower for technical reasons).

If you have a 50 amp 240 volt circuit, you can have as much as a 9600 Watt EVSE. That will charge your EV's battery to 80% that much faster, only 3.3 hours.

The EV manufacturer may recommend a certain level of charging, but in the end, your EV doesn't really care. It will happily accept whatever the EVSE can deliver. But YOU may care if you want the EV to charge faster, so you can get on your way sooner.

Therefore, if you didn't tell your electrician to install a specific EV charging circuit capacity, he did nothing wrong. He gave you a circuit that can power a 5760 Watt EVSE. (Actually I've never seen a 5.76 kW EVSE mentioned, but I have seen 5 kW and 5.5 kW.)

If you want higher power charging, then you can upgrade the circuit. I don't see that as the electrician's responsibility.

However, as others have said, for goodness sake don't just change the breaker and receptacle to 50 amp but leave the AWG 10 cable in place, unless you strongly dislike your EV and garage, and have outstanding fire insurance coverage.

One more thing, I don't recall ever reading about an EVSE that required a 240/120 volt circuit. There may be some, but all that I've heard of only need 240 volts. So you should need only 2 power wires and an equipment ground conductor in your supply cable.

I hope this helps.

I wrote this yesterday, but I guess I forgot to press "submit". Micah (the OP) did say that he would change out the wire to 6 Ga, for the 50A service. However, I don't think that's for Level 2 service, it's for higher current. The higher current chargers are different for different car makes. Most Japanese EVs use the CHAdeMo standard, most others do not. As far as I know, however, all can use Level 1 and Level 2.

The SAE defines EV charging by Levels 1-3, and by AC charging (using the EV's onboard charger) vs. DC charging (which uses an offboard charger inside the EVSE).

SAE Charging Standards

Level 1 AC charging is up to 1.9 kW.. Normally it's at 120 volts only.

Level 2 AC charging is up to 19.2 kW. It's at 240 volts (I think also 208 volts). So Level 2 AC charging goes up to 80 amps at 240 volts.

Level 3 AC charging is 20kW+. (I don't know what you'd call 19.9 kW AC charging.) I don't know of any EVSE that offers this, or any EV that accepts it, but they might emerge someday.

Both Level 1 AC and Level 2 AC are pretty well standardized, so any recent EV can charge from any recent Level 1 or Level 2 EVSE. Both use the J1772 plug to connect to the EVs.

But wait, there's more! Both Level 1 and Level 2 can also refer to DC charging. The DC charging power values for these levels are MUCH higher than AC charging power.

Level 1 DC charging can be as much as 36 kW, so it actually provides more charging power than Level 2 AC charging. Level 2 DC charging goes as high as 90 kW. Level 3 DC charging is 90-240 kW.

In practice, most (all?) Level 1 and 2 charging is AC, and most (all?) Level 3 charging is DC.

Level 3 DC is what you use for fast charging on long trips. But there's a big problem with Level 3 DC charging: incompatible systems.

They include CHAdeMO, which generally speaking the Japanese automakers use; and CCS, which is more favored by European automakers such as BMW and VW. There's a third Level 3 DC system in China, but I don't know anything about it.

Finally standing all by itself is Tesla's Supercharger, which AFAIK nobody but Tesla owners can use.

There are adapters for Teslas to use one or both of the other standards, but not the other way around. I've heard of people trying to crack into Superchargers for other brands of EVs, but don't know how successful they've been. Tesla would probably throw fits if they were.

AFAIK there are no adapters yet between CHAdeMO and CCS.

So if you have a Tesla, you can pretty much charge anywhere. Other EVs, not so much.

To put it bluntly, this incompatibility stinks. Imagine how much fun you'd have gassing up your car or truck if there were 3 different kinds of gas pump nozzles, and every time you stopped for gas on a trip, you had to look for a gas station with the right nozzle for your particular brand of vehicle.

That's the imbecilic situation we have with EVs right now. I sure hope that we see one of these Level 3 DC charging "standards" emerge as dominant, something similar to the VHS and Blu-Ray victories. That would make fast on-the-road EV charging as universal as gas pumps. I'm not holding my breath for it, though.

If I was building a new house and thought I would need a EV charger in the future, it seems that the simple solution might be to ask for a 60 to 100 amp subpanel installed in the garage near the vehicle parking area, and leave the charger specification open until you actually get a vehicle and charger. Then add a breaker in the sub-panel and make the short connection to whatever charger is purchased.

Bruce

mtv:" I would need 10/3 + ground for the level 2 charger I want to install. I need to run the line about 100 feet from my house to a convenient charging location. "

At that length, I would seriously think about using 8/3. There are per-foot loss equations, but I'm too lazy to look them up.

Since we're pumping electrons into a battery, AMPS is a better number to use rather than WATTS. However, they are directly related.

" (Actually I've never seen a 5.76 kW EVSE mentioned, but I have seen 5 kW and 5.5 kW.) "

That's because you used 30 amps in your figures. They would need to be less in order to use a 30-amp circuit at a lower amperage.

" If you have a 50 amp 240 volt circuit, you can have as much as a 9600 Watt EVSE. That will charge your EV's battery to 80% that much faster, only 3.3 hours. "

In the olden days, it was assumed that charging at home would be over night or 8 hours. Now apparently folks want it faster. If you want faster, upgrade your circuit.

" One more thing, I don't recall ever reading about an EVSE that required a 240/120 volt circuit. There may be some, but all that I've heard of only need 240 volts. So you should need only 2 power wires and an equipment ground conductor in your supply cable. "

That may be. But the Tesla document he referenced above required a 240/120vac connection. It wouldn't surprise me if the EVSE has some electronics in it that are powered by 120v rather than 240v.

" Imagine how much fun you'd have gassing up your car or truck if there were 3 different kinds of gas pump nozzles, and every time you stopped for gas on a trip, you had to look for a gas station with the right nozzle for your particular brand of vehicle. "

Don't have to imagine. I'm old enough to remember this when lead was removed from gasoline. There were two different nozzle sizes, and the old nozzles would not fit in new cars.

I ran 6 gauge to both parking spots in garage. Worth the few extra bucks - they are very close to our main breaker box.

Will probably do the 14-50R that Tesla uses for one and the 30 amp one that our Leaf uses for now. The Leaf only charges at 20A so 6 gauge is overkill but future proofing makes sense.

My Tesla only has 40 Amp charging so you can get away with 8 gauge - with some limitations - but just use 6 gauge.

FWIW - different Teslas use 32A, 40A, 48A or 80A on board chargers. So it is easy to get confused.

Outlets are very easy to change out but wires are a pain.

"At that length, I would seriously think about using 8/3. There are per-foot loss equations, but I'm too lazy to look them up."

IIRC, the code recommends, but doesn't require, a maximum of 5% voltage drop. At 24 amps (80% load), 200 feet of AWG 10 copper wire (0.2 ohms) has a voltage drop of E = I * R = 24 * 0.2 = 4.8 volts, which is 2% of 240 volts.

So you'd be well within the guidelines with AWG 10 cable.

You could go with the larger wire and get improved efficiency. At 24 amps (80% load), 200 feet of AWG 8 copper wire (0.126 ohms) has a voltage drop of E = I * R = 24 * 0.126 = 3.024 volts, which is 1.3% of 240 volts.

"The Leaf only charges at 20A so 6 gauge is overkill but future proofing makes sense."

Just make sure that the terminals on the breaker and receptacle you use are rated for the size of the conductor you install.

For example, a Square D QO 30 amp breaker is rated for wire sizes from AWG 14 to AWG 8. Installing it with AWG 6 wire would be a code violation, and might not even be physically possible.

"'(Actually I've never seen a 5.76 kW EVSE mentioned, but I have seen 5 kW and 5.5 kW.) '

"That's because you used 30 amps in your figures. They would need to be less in order to use a 30-amp circuit at a lower amperage."

Not really. I calculated in the 80% continuous load factor: 30 * 240 * 0.8 = 5760.

I guess I wasn't clear. Sorry. I was just trying to point out that nobody I know of manufactures a 5.76 kW EVSE, so you'd have to install one below that capacity (such as 5.0 kW or 5.5 kW).

"Don't have to imagine [incompatible gas stations]. I'm old enough to remember this when lead was removed from gasoline. There were two different nozzle sizes, and the old nozzles would not fit in new cars."

I was there too! But as I see it, there are a couple of differences between then and now.

One difference is that unleaded pump nozzles would fit into older cars designed for leaded fuel, whereas CHAdeMO and CCS connectors and data formats are totally incompatible..

So today, you can't use a CHAdeMO EVSE with your BMW I3; but back then, you COULD pump unleaded fuel into your 1962 Ford Galaxie. (However, if you had, your car's engine might have been damaged.)

The other difference is that (as far as I can recall) every gas station had both leaded and unleaded fuel for many years after the 1975 introduction of automotive catalytic converters.

FWIW, I’ve had an EV for 5 years now. City commuter only. 6000 miles/year.

Never bothered to install a dedicated EV circuit but just use an extension cord from a standard 110V/15A outlet.

Yeah, compared to a gas station use model it’s hopelessly slow but in reality my car just sits there anyways for hours and hours and hours and it’s full in the morning.

Never had a problem charging it. And I hook it up maybe 2-3 times a week.

If you don’t need to travel 100 miles/day and can charge overnight the charging speed problem isn’t really one.

But.... that 120V extension cord charging is inefficient and relatively dangerous. I know that at least some manufacturers forbid the use of extension cords. It still works of course but there is a voltage drop and excess heat generated - in something possibly not designed for continuous use.

On a Leaf - the efficiency falls by about 30% when using 120V charging instead of 240V. That is because there is 300W overhead that now runs all night instead of an hour. The voltage drop on the extension cord just adds some more to that.

I have done 120V for limited times but like most people, there are some days when driving is more than just to and from work. You limit the usefulness of an EV with just 120V.

I had a 50 amp circuit with a NEMA 15-50p plug run into my garage to charge my car. I use a Juicebox pro 40 EVSE that I bought 3 years ago or so : https://emotorwerks.com/store/residential/juicebox-pro-40-smart-40-amp-evse-with-24-foot-cable (This is an updated version of the box I bought) I had it installed originally at my previous house and took it with me when I moved. To be honest, I don't remember what gauge wire the electrician used in either case.

I agree with David Cary in that you can limit yourself if you reply on 120v charging - I did that for a year and it took some planning in the early months to make it work. Things were much better once I switched to 240v charging. My current car is a LEAF and my total daily driving is around 55 miles. I'll be a Tesla owner at some point in the near future, but I'll likely continue to use the same Juicebox.

As David Cary pointed out, some mfrs "prohibit" use of an extension cord for 120 volt charging, but I don't see what's wrong with a 12Ga extension cord, designed for room air conditioners. My car (a Mitsubishi PHEV) uses 8 or 12 amps, taking 13 or 8 hours respectively to fully charge the battery, which has about a 22 mile range. I've been thinking about a level 2 charger (240 volt), but don't see any reason to spend $400-$800 for the charger, plus the cost of wiring. Now, if I had a car with a larger battery...

"extension cord charging is inefficient and relatively dangerous."

If you use an AWG 12 extension cord with high quality connectors (not the cheap ones sold in the home centers), you'll be fine.

At our primary residence we have 240v/80a Tesla EVSE's. Maybe once a year we're glad to have the extra charging speed but otherwise we'd be OK with much less.

At the beach house we rent (snowbirds) we do about 99% of our charging (for 3 months each year) with a standard 15a wall outlet because that's all that's there and it's enough. A couple of times I've unplugged the dryer to get a faster charge. I should probably note that nearly all of our local transportation (Marco Island) is by bicycle so it's not unusual for our car (Model S) to not get used for several days at a time.

At the new house we're building we're wiring for 240v/100a at each garage stall but w/ 80a breakers. Overkill but the extra wire cost is minimal and that will set us up for any future demands. These, along with charging for boats, lawn tractor, etc. are all off of a Time-Of-Day meter with lower nighttime rates. We do have solar but it works out better to sell to them at day rates and buy at night rates.

BTW, extension cords are totally fine so long as they are of sufficient gauge and have proper plugs on each end.

“But.... that 120V extension cord charging is inefficient and relatively dangerous. I know that at least some manufacturers forbid the use of extension cords. It still works of course but there is a voltage drop and excess heat generated”

The voltage drop equals current multiplied by impedance. I use a 12ga extension cord and a 20A rated outlet (12ga wiring). Therefore impedance is low and the excess “heat” can barely be felt so I think I’m good with this setup.

I’m not advocating it (it’s a lazy solution) but my point was that range and charging times may not be the problem that the vast majority seems to think. It’s by far the most asked question I get when someone hears I drive an EV. What’s the range and how long does it take to fill up”?

The ICE usage model where people fill up twice a month in 2 minutes and get 400 miles of range is so powerfully ingrained in people’s minds that range and charging times are misapplied to at least a city commuter vehicle that can be charged at home overnight and doesn’t require a trip to a gas station. If one drives 20 miles/day average, neither range nor charging times matter.

I have a gas SUV for travel.

"range and charging times are misapplied to at least a city commuter
vehicle that can be charged at home overnight and doesn’t require a trip
to a gas station."

Agreed. That works out well when you have two vehicles.

I'd like to see EVs with user-swappable batteries, so that you could buy your EV based on your daily use, and not pay for a big battery you didn't need. If and when your commute changed and you needed more range, you'd just trade in your small battery for a larger one.

You need to go to a professional electrical forum.

https://www.bing.com/search?q=electrical+forum&qs=AS&pq=electrical+fo&sk=LS2AS1&sc=8-13&cvid=2D58A9247A464F54B8F3488A06392760&FORM=QBLH&sp=4