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Want to buy a Model S but ... only 100 Amp 240 volt incoming circuit to the property (condo)

Here is my problem :

I live in a condo and have my own garage. The HOA is ok with me installing a power outlet and fuse (nema 14-50) provided it is done with a permit by a licenced electrician. Even though the garage is for my exclusive usage only it is considered common property.

Here is the problem : the Main breaker for my unit sits in the shared utility closet. This is a 240 volt 100 amp circuit.
the panel is shared with 7 units and is a 1200 amp panel.

According to the NEC and California electric code a load calculation is in order to figure out if the 50 amp fuse and Nema 14-50 can be installed or not.

And this is where the misery begins...
i can't make heads nor tails from this calculation and get a lot of conflicting information.

Every major appliance in the house is GAS apart from an oven in the kitchen.

Here is my fuse box breakdown
15 amp : hallway / entry/ living room
20 amp : FAU (furnace and air handler)
20 amp dining area
20 amp microwave
20 am kitchen gfi 1
20 amp kitchen gfi
20 amp garage gfi
20 amp house gfi (bathrooms)
15 amp bedroom 3
15 amp master bedroom
15 amp bedroom 2
15 amp entry and stairwell
30 amp 240 volt for Oven ( two linked fuses 30 amp each )
20 amp garabge disposal
20 amp dishwasher
40 amp AC 240 volt ( 2 linked fuses )
20 amp laundry
20 amp laundry

i have the real appliance power rating:
microwave 1650watt
oven : 2700 + 3600 watt
dishwasher : 10.5 ampere
clothes washer : 10 ampere
clothes dryer : 6 ampere

can someone figure this one out ?
i did a couple of excercises and always end up around 24000VA ( sometimes 100 Va below, sometimes 300 Va above )


Best thing would be to have a licensed electrician come out and bid the job for you. I'm thinking he'd have to do the calculation for his bid, so you'll find out if it's ok out not.

It seems to me you should be able to install it, though you might not be able to use it when the AC is on without dialing down the amps.

I think you will need an electrician, but pretty clear to me that you do not have enough power for an additional 40amp continuous load.

If the AC and oven are on at the same time that would be about 50; add 40 for the Tesla and that leave 10 for everything else.

I think the question for an electrician would be how big a breaker can you put in for EV charging?

If there are 7 units and 1200A available, how come you only get 100? Do 4 get 200 and 3 get 100 and 100 for the association (outdoor lighting, for example)?

The panel might be able to handle it. Electricians do a percentage load for all 120V loads (all those 15 and 20A breakers), and then add up total combined load for 240V appliances. But even if it can't, upgrading the panel to a 125A or 200A panel isn't the end of the world. The condo in total has more than enough power. Time to get quotes from electricians.

to clarify :

- the main panel is labeled 1200 amp , but each unit only has a 100 amp fuse. i do not know what is the real power coming in to the panel .

upgrading is most likely not possible as i would have to run new cabling from the meter panel (where the 100 amp fuse is) to my fusebox. that is over 100 ft ... and that cable runs through the other properties. (i'm opposite corner )

Besides, i do not want to spend 2 or 3K on infrastructure of a property i may leave 3 or 4 years from now...that is wasted money.

You can do a few things:
a) use the charging time to charge in the middle of the night, when the oven and dryer aren't going to be running. If you fail to do it properly, you will trip your main breaker.
b) run a 30A outlet instead, such as a NEMA 14-30. You will get a slower charge, but it will be plenty sufficient for nearly all of your needs.
c) pay to upgrade your panel to 200A. The main panel is 1200A and only 7x100A subpanels off it, so it shouldn't require any change beyond the wire to the main panel and your subpanel. It won't be cheap though.

Ideally, you would be able to find out how much power you run through your main breaker with everything turned on - you may find an electrician who can measure that, or you can get something like the TED5000 to monitor it. That would let you know just how much room you have, though it sounds like your code is going to require a calculation to their satisfaction anyway.

If the town you are in requires a permit then it may not be possible. Another 50amp circuit will trip the 100 amp breaker under the right conditions. If a permit is not needed, which is what I think, then just have the electrician install the circuit. Don't charge the car is the ovens and ac are on. Now that I read all your loads that should be a 200amp panel. HHMM. Get an electrician out there.

@mrrjm - the existing circuits can already trip the main breaker under the right conditions. That isn't a safety issue, as the breaker in the main panel protects the wire and subpanel.

I'm getting along just fine with a 20A/240V outlet--adds 12 MPH which should suffice unless you have a long commute.

You have a problem that will be repeated a million times in the next few years. Not easy to solve. The sad thing is I see very little new construction that is planning for this.

One upside is that many of the Tesla buyers today are involved in the real estate development market. As they solve problems charging their own cars the light will go on that future developments need to plan for this electrical load.


Coordinate an electrician with your HOA is best.

If there's an existing 110V outlet in your own garage (at least there's 1 for the garage opener) then may be you can use it if your commute is not that long.

You could max charge with HPWC in 5 hours after work on Friday night, then off you drive to Grand Canyon National Park early Saturday.

With 110V, you have to fill up your battery on Friday, Saturday, and Sunday to get it ready for a work week starting Monday. All work and no play for you, unless....

Unless you can access Supercharge then you can play all you want by just stopping by it!

It's going to come down to what the electrician thinks he can get in the box. Don't rule a Tesla out until you have him take a look.

I don't have any charging in my apartment at all, and I manage quite well.


What is the 240V 40-Amp circuit you have listed in your fuse box for? You did not designate anything assigned to this?

You might ask an electrician if he can install a switch on your oven circuit, and run a second leg out to the Garage. I am not an electrician, and do not know if this is against code, but you could have it power one circuit or the other - charging the MS after dinner etc. It may be an inexpensive option.

Unless you do a lot of driving every day, you don't need a full 50A circuit. A 30A circuit or even a 20A 240v circuit will most likely suffice. Ask an electrician what the max he thinks he can put into your existing panel and go from there. How much driving do you typically do?

After reading all the comments I would believe Jat is the closest in a correct answer. The charge at night part only.

As long as you set the charging at night (Which can be set from within the car settings) then you will/should have no problems at all. The only thing that might run at night would possibly be the AC and the dryer. Avoid using the dryer during your charging time and everything "should" be great!

Email me if you would like more info on how electrical load calculations work.

Brian Wuttke
BW Electric

i agree that 20 amps or 30 amps (240 volts) is likely enough for home charging. That will put over 100-150 miles of range on our car each night. Most people don't arrive at home with an empty battery. Odds are that you are doing way less than that each day. Think about your daily commute and if that works.

I am not worried a out my 'real power draw' . It's the permit i am worried about !
Be ause this is in a common area a permit is mandatory. It needs to be signed off by an inspector. These guys require load calculations.

My normal power consumption in the house ivery low. The bedroom , halway and kitchen circuits don't co sume anything. There is mereley a few clock radio's and a few led lightbulbs on those... I dont have any small kitchen applieances like toaster oven.

My peak daytime load would be AC running and washer and dryer and dishwasher and oven running. That would draw 87 ampere total. Add some small stuff like the tv and a computer or two and you climb to 95 ampere.

Now, at night , when the tesla is programmed to commence charging after 10pm and terminate before 4am
All that stuff falls away. Only the AC would run. And thats 30 ampere... Add some grossly overstated, vampire draw from clockradio and other stuff in standby and you end up at 50 ampere.
More than enough margin to feed 40 amp to the tesla.

So technically i can manage this perfectly.

The problem is not that. Its convincing the code inspector to sign off on the install !

Well, none of us know your local code or exactly what the load calculation looks like. If it's anything like my city, getting access to it is quite hard - I finally found I could look at the local code physically in the city office during business hours.

Your best bet will be to call an electrician who can do the load calculation and probably won't charge you more than an hour of your time, and might not even charge you for it if you get them to do the work.

I had the same issue. However, at the same time I decided to change out my electric stove for a gas stove. I got a great deal at Best Buy, and it was not that much to run a gas line to the kitchen. I much prefer cooking on a gas cook top. This freed up the circuit that fed the old stove. My breaker panel was in the garage anyway, so running the line and installing the NEMA 14-50 was inexpensive as well.

Vincent. I agree with the others about getting a couple of electricians' opinion/bid. Keep in mind, you will be charging in the off hours (12AM-7AM) when you will have minimal draw. I think you are fretting over a hypothetical problem.

Wait a second, if your only electric appliance is the oven then just use the circuit dedicated for the dryer for charging. Or, check if your oven has a gas feed capped off behind it and buy a gas oven, then use that circuit for charging.

Switching out the electric oven is not an option. This is a wall mount oven and not a range. (the oven and burners are separate in my kitchen. Burners are gas. oven is electric.

There are no wall mount gas ovens in single unit. i checked all the big manufacturers like Samsung, GE , LG Whirlpool and many others. Nobody makes this.

So that avenue is closed.

Now. Anyone got experience charging the car from a a 14-30 outlet ?
I may be able to get away easily by having a 14-30 circuit added. the 14-50 will be very difficult.

There is other confusing things in the electical code.

According to California electrical code a Level-II electrical vehicle charger (240 volts-40 amp) needs to be permanently wired. But the Tesla does not use a Level-II charger (unless you get the 80 amp charger) . It only uses a 240 volt power outlet... So what do i need to get a permit for ? for a dryer plug ? Do i even need to mention that this is to charge an electric vehicle ?

The problem is the electricians i talked to have no experience with Tesla cars... so they don't know what to do.

somebody should have the answer to this one.
- How to correctly declare what you are installing : is it an EV charger ? is it a dryer outlet ?
- Get the appropriate permit
- Do the load calculation
- get it installed.

If you have a clothes dryer, you could install the 25A dryer plug for the model S- the extra adaptor is $50 or something. I charge at 20A (less loss due to heat in charging) and it's plenty fast.

Oh and in my state any electrical work needs a permit. Good news is, the Feds give you a 30% tax credit on the work, and my state waives sales tax for 'electrical vehicle charging infrastructure.'

You don't need to discuss with the electrician what is being charged by a 14-30 outlet, just like you don't need to tell him whether you plan to plug a blender, toaster or whatever into a 110 outlet. This is not a dedicated EV charger, it could be used for absolutely anything - if not by you, then by future residents of the property.

(I hit submit too soon...)

So an electrician doesn't need to know anything about Tesla cars any more than they need to know about blenders or toasters.


The switching for the oven would not be ideal, but I assure you it could be done. I am not an electrician, but I am an Electrical Engineer, I just have no experience in residential wiring and NEC code.

If the oven switch is not an option for you, you could install a level-II charger. I read the Specs on the J-1772 connection, (which is an adapter included with the Tesla Mobile charger that comes with the vehicle), and they are supposed to be able to handle up to 80-Amps. If you were going to go to this length, however, you might as well install a HPWC. Whatever you do, it should increase the value of your condo. This of course would require tapping in to the Main Panel and running another 100-Amp line to your condo, and would be expensive.

I also received an advertisement e-mail this morning, from a company that is building EV charging infrastructure, and it looks like they are working in California. I am attaching the link for your reference. You may be able to talk the Condo management into installing a community charging station/stations. In any event, check out the link. With the CHAdeMO adapter coming soon, it may be an option for a Level-III High power DC charger for your Condo community. With the number of EVs in CA, I would think the management would be open to it.

good luck

One more suggestion. We have another home, where the dryer is located just inside the door from the garage. For a while, I used a very heavy extension cord and an adapter to plug into the dryer plug. I had an electrician install a switch so that the power coming to the dryer could be diverted to a line in the garage, where another receptacle was mounted for the car. I leave it switched to the car plug unless I need to use the dryer.

Your are getting yourself tied up in knots. By code, you don't need to know what will be plugged into a standard electrical plug. Just ask for a nema 14-30 and be done with it. By the way, you haven't answered my question, how much driving do you do?

Also, people that are saying, well just charge at night, so there is no problem are also missing the point. If you need/want to get a permit, then the code assumes the plug can be used any time of the day, because at some point, it will, whether by accident or design.

@mrspaghetti, actually you should tell him it is to charge a car. Code in my state is pretty specific about breaker vs continuous draw because the car will draw high power steadily for hours.... whereas the dryer or oven heaters go on and off - dont have the steady state draw that a car does.

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