Condo owner -- NEMA 14-50 with 100amp service (gas heat/stove/dryer/hot water)

tanker5 · Nov 16, 2015

I live in a townhouse style condo with an attached garage and am expecting to take delivery sometime next month. My electric service is 100 amps. I have natural gas heat, with a gas stove/oven and gas dryer and gas hot water heater. My air conditioner runs on a 30 amp circuit. Other major appliances are refrigerator and microwave and dishwasher.

I asked my Tesla-recommended electrician if he recommends me installing a 30 amp outlet or a 50 amp outlet (typically, I drive about 40 miles/day). He told me I should be fine having a NEMA 14-50 outlet on a 50 amp circuit installed since I have gas heat and hot water, etc. the installation was completed a few days ago.

I can't help but be concerned about the amount of power being drawn in the summer with my air conditioning running and my car charging. Should I be concerned, or am I worrying about this for nothing??

David_Cary · Nov 16, 2015

Well - if you are concerned, you should know that you can set the car to only charge at 30A (or 27 or 10). Then if you need the 40A one day, you can easily change it back. You most likely will need/want 40A in the winter so that works well.

Your A/C probably pulls significantly less than 30A once it starts. So there is that.

I have a 4 ton unit that pulls about 20A when running. I would think a condo in CT would not need even 4 tons.

But even if you are charging at 40A, a/c at 20A, that still leaves 40A. Without heat making appliances, it is very hard to use that much electricity. I have an energy monitor so I know what I use.

You can do it but it would be very hard (microwave, toaster oven and dishwasher all running) and what would happen - the breaker would pop. Not the house burning down.

Set the car to 30A in the summer. Done.

Rockster · Nov 16, 2015

And you can program the car to charge at night when your AC is running less. That's what I do in the summer months here in Texas.

paulkva · Nov 16, 2015

In addition to David's excellent points, you will likely do most of your charging overnight, at which point the other appliances (even the AC) won't be working as hard, if they're running at all. So I don't think you'll have to worry, even at 40A. On top of that, if you drive 40 miles/day, you could probably set the car to charge as low as 10A and still regain 40+ miles overnight (not that I'd recommend doing so).

cinergi · Nov 16, 2015

You'll be fine. I had the same setup at my previous home for a couple years -- and I didn't pay attention to what time of the day I charged the car.

AB4EJ · Nov 16, 2015

cinergi said:
You'll be fine. I had the same setup at my previous home for a couple years -- and I didn't pay attention to what time of the day I charged the car.

Agreed. All your big appliances are gas, you have very little load on your electrical system.

FlasherZ · Nov 16, 2015

A/C condensor units and blower units usually have a larger breaker for initial start-up load. Once they're running (after a couple of seconds start-up), the load is much lower than the breakers might indicate. The only thing that would really concern me competing in a condo on a 100A service would be electric heat. There are several "load calculation" tools on the 'net that can help you, but just from your description I think you're good.

jkliu47 · Nov 16, 2015

OP, I own a single family house, and except for an extra refrigerator in the garage, have the same appliance setup as you. When I planned for the Tesla and installed a 14-50 power source in the garage, I didn't increase the 100 Amp service to the house because of the prohibitive cost of trenching and laying the extra power line from the utility power source.

Except for a few instances in summer nights when my AC kicked in after midnight (when the Tesla charging is scheduled), I have been able to charge at full 40 Amps with no hiccups. Even then with those instances the current software senses the voltage drop at the charging port and automatically drops the charging current to 30 Amps and continues charging.

Rocky_H · Nov 17, 2015

Our situation is kind of similar to yours, and it’s not a problem because of the offset day/night things. Ours is a 1600 sq ft house that has a 125A main service. We do have A/C, oven, and dryer that are the big electric loads. But since oven and dryer are something you run on purpose, it’s easy to just not use them in the middle of the night when the car is using the 14-50. And I have the car set to use only 31A anyway, so it’s a little less.

David29 · Nov 19, 2015

tanker5 said:
I live in a townhouse style condo with an attached garage and am expecting to take delivery sometime next month. My electric service is 100 amps. I have natural gas heat, with a gas stove/oven and gas dryer and gas hot water heater. My air conditioner runs on a 30 amp circuit. Other major appliances are refrigerator and microwave and dishwasher.

I asked my Tesla-recommended electrician if he recommends me installing a 30 amp outlet or a 50 amp outlet (typically, I drive about 40 miles/day). He told me I should be fine having a NEMA 14-50 outlet on a 50 amp circuit installed since I have gas heat and hot water, etc. the installation was completed a few days ago.

I can't help but be concerned about the amount of power being drawn in the summer with my air conditioning running and my car charging. Should I be concerned, or am I worrying about this for nothing??

My condo is somewhat similar -- 100 amp service but my unit also has a 30-amp circuit for an electric dryer (so that people can install either electric or gas) and has a 50-amp circuit for the AC. Since we have a gas dryer, we do not challenge the 100-amp breaker but I assume that the service is adequate for use of an electric dryer when the AC is on. So my guess is that you would also be OK because your charger circuit is more or less equivalent to our (unused) dryer circuit. And as others said above, you can adjust your maximum charging rate if you find there is a problem in the summer with the A/C on. (And I envy you, by the way. We have not yet been able to make arrangements to charge here. Our condo is a flat with no garage and no obvious way yet to provide charging. I am working on it with the condo board...)

green1 · Nov 19, 2015

Not a condo, but my house also has 100A service, I also have natural gas heat, stove, and hot water. Difference from OP is I have an electric dryer, but no AC
Big electrical loads include:
- Hot tub (50A breaker, doesn't seem to ever draw more than 30 though, even with startup surge from the pumps)
- Tesla (50A breaker, stuck at 32A charging due to Tesla's new crippled Canadian UMC)
- Dryer (30A breaker, unknown draw)
No other loads over 15A, do have the furnace blower motor, fridge, microwave, dishwasher, washing machine, kettle, hair dryer, etc.

No issues so far, and the electrician I talked to before wiring in the Tesla said there was no problem doing this.

I'm considering getting a HPWC, but before I do that I'd probably upgrade to a 200A service entrance to allow for full 80A charging on my dual charger car.

pears · Feb 9, 2018

I have 100A service in a condo building and unfortunately have electric everything (baseboard, washer/dryer, stove). Is it feasible for me to even get a 30A circuit with that, or is it possible to get a new service from the electric company specifically for a charger?

Lloyd · Feb 9, 2018

tanker5 said:
I live in a townhouse style condo with an attached garage and am expecting to take delivery sometime next month. My electric service is 100 amps. I have natural gas heat, with a gas stove/oven and gas dryer and gas hot water heater. My air conditioner runs on a 30 amp circuit. Other major appliances are refrigerator and microwave and dishwasher.

I asked my Tesla-recommended electrician if he recommends me installing a 30 amp outlet or a 50 amp outlet (typically, I drive about 40 miles/day). He told me I should be fine having a NEMA 14-50 outlet on a 50 amp circuit installed since I have gas heat and hot water, etc. the installation was completed a few days ago.

I can't help but be concerned about the amount of power being drawn in the summer with my air conditioning running and my car charging. Should I be concerned, or am I worrying about this for nothing??

I had a situation almost exactly the same with a condo I had in San Diego. I installed a 14-50 and found that I could charge the car at 40 amps, run the air conditioning, lights and one other major appliance. I limited the charging to the evening in most circumstances and had no problems whatsoever.

Nitemare3219 · Feb 13, 2018

pears said:
I have 100A service in a condo building and unfortunately have electric everything (baseboard, washer/dryer, stove). Is it feasible for me to even get a 30A circuit with that, or is it possible to get a new service from the electric company specifically for a charger?

Be diligent in your charging & appliance use and you will be fine even with a 50A circuit. Don't charge the car at 40A with the AC running, clothes drying, and making Thanksgiving dinner with the stove/range. Charging overnight when sleeping is the safest bet, followed by drawing back charge current to around 30A (or even less if necessary). Helps to have efficient appliances & lighting fixtures as well.

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Condo owner -- NEMA 14-50 with 100amp service (gas heat/stove/dryer/hot water)

tanker5

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David_Cary

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Rockster

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paulkva

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cinergi

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AB4EJ

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FlasherZ

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David29

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green1

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pears

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Lloyd

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