TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

200, 300, or 400

Discussion in 'Charging Standards and Infrastructure' started by Gynob001, Feb 3, 2014.

  1. Gynob001

    Gynob001 Member

    Joined:
    Aug 1, 2013
    Messages:
    152
    Location:
    Orlando
    I am planning to buy a new home and the builder gave me the option of 200, 300, 04 400 amp circuit. It will be an all electric house and I keep my Tesla Model S85 plugged in whenever I am at home.
    Is it safe to have a higher amp circuits (the difference between each is about $2000)?
    In my neighborhood, almost all houses are wired for electric cars. Interesting that they all have outlets on the wall closest to the house while I believe that most electric cars have ports on the bak side or to the back left. I hate to drag the long and heavy cord across. It cost me about $500 to have the outlet moved to the side wall!
     
  2. yobigd20

    yobigd20 Well-Known Member

    Joined:
    Oct 28, 2012
    Messages:
    5,793
    Location:
    Skaneateles, NY

    Well, I'm sure 200 would be fine, but if it were me I'd be going for the 300 or 400. Probably 400. that's because in 15 years when my wife as an X and my 3 kids each have an E, I'm going to need that kinda of power to charge 5 Tesla's simultaneously. Hell I might even have more when the supercar and the trucks and crossovers come out too. I think I might need a mini power plant in my back yard.
     
  3. dflye

    dflye S Sig Perf 414, VIN 814

    Joined:
    Oct 7, 2011
    Messages:
    569
    Location:
    Raleigh, NC
    I think the builder is referring to the amperage of the main breaker panel and the related feed into your house. Basically it is the size of the incoming hose for electricity, and potentially the amount of expandability in the future (especially if the larger amperage panels come with more open slots) Amps don't kill, volts do, and that number won't change with the increased amperage capacity of the higher rated main breaker panels.

    Depending upon size of home and various appliances (such as range, dryer and water heater) using electricity or not, 200A may be just fine. We have a reasonably large home (a bit over 4,000 heated sf), 3 A/C units and a mixture of gas and electric appliances and a 14-50 plug in the garage for the car. We've gotten along just fine with a 200A main panel, although we added one sub-panel from that when we finished the basement and another in the garage when we got the car.

    If the larger amperage mains provided more room for expansion, I'd likely get the 300A and perhaps the 400A; while 200A may suffice your needs, always nicer to have one clean breaker panel instead of multiple or using a bunch of doubled up breakers.
     
  4. Rockster

    Rockster Active Member

    Joined:
    Oct 22, 2013
    Messages:
    1,005
    Location:
    McKinney, TX
    Considering the much higher cost of retrofitting a higher amperage capability at some point in the future, I would definitely lean towards 300 or 400 now.
     
  5. Cottonwood

    Cottonwood Roadster#433, Model S#S37

    Joined:
    Feb 27, 2009
    Messages:
    5,062
    Location:
    Colorado
    If you are into electric cars and/or solar PV, get the 400Amp service and put a 200Amp sub panel in the garage during initial construction. It will be a far less expensive install then. I would even recommend putting in an HPWC and a 14-50 in convenient locations in the garage at the same time.

    Lastly, even if you don't put in a backup generator now, put in a 70Amp sub panel that runs all of your essential circuits. Feed this through a manual transfer switch in the garage. This will let you power critical circuits with a portable generator for now, and will greatly simplify the connections if you put in a permanent backup generator later. If you are really into the backup power to charge your Tesla, you can run a 14-30 off of that little 70Amp panel.
     
  6. PhilBa

    PhilBa Active Member

    Joined:
    Apr 20, 2013
    Messages:
    1,355
    Location:
    Seattle
    Agree with Cottonwood - get the largest you can now and set up the subpanel. Design the electrical for a generator fed transfer switch. Not cheap now but way expensive later. Good selling point for the house downstream.
     
  7. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    Interesting that they give you a 300A option.

    In the US, you typically see two sizes of service put in today, 200A or 400A (also called 320 in some cases). 200A is provided on a single service panel, while 400A is generally provided with 2 200A panels that feed from separate lugs at the base of the meter (because service equipment rated > 200A gets expensive very fast). My recommendation is similar to Cottonwood's, although I always suggest one of the 200A panels for the critical circuits and one of the 200A panels for the non-critical circuits. You can always add a transfer switch and connect a whole-home generator later. My home is set up in this way.

    As mentioned, while it's being built I'd suggest a 150A subpanel in the garage for EV charging, which will accommodate up to 3 14-50 outlets or an HPWC + 14-50.
     
  8. Al Sherman

    Al Sherman It's about THIS car.

    Joined:
    Nov 29, 2012
    Messages:
    1,692
    Location:
    Batesville, IN
    400A. I wouldn't consider less unless I were building a hunting cabin, or a very small second home.
     
  9. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,753
    Location:
    Texas
    Go for the largest you can afford. Even 600 might be too small five years from now.
     
  10. miimura

    miimura Active Member

    Joined:
    Aug 21, 2013
    Messages:
    1,244
    Location:
    Los Altos, CA
    #10 miimura, Feb 3, 2014
    Last edited: Feb 3, 2014
    I just finished a custom home for my family last year. I discussed it with the PG&E project engineer and we agreed to 400A (some part of it is only 320A). When the electrician put in the panel I immediately noticed that it was only 200A. I had to argue with him that the 400 was justified and he finally relented when I told him that the solar needed two 30A 240V breakers. He already accounted for the two 14-50's in the garage and the 14-50 for the 48" range, two 30A A/C units and the 30A dryer outlet. He up-charged me about $1,500 for the 400A panel because the GC didn't specify it in the bid paperwork. If you're building new, just go big now. The cost to change it later will be far more.

    BTW, I put my 14-50's on the middle of the two side walls of the garage. I use the one in the left space for my RAV4 EV because it has the charge port at the left rear like the Model S. Volt and Energi cars are also on the left side, but ahead of the driver's door. The Leviton EVB40 EVSE I use has a 25 foot cord, so I can reach both garage spaces and at least one driveway space - both if backing in a car with a rear inlet.
     
  11. derekt75

    derekt75 Member

    Joined:
    Jul 16, 2012
    Messages:
    592
    Location:
    San Jose, CA
    really?

    I find it surprising that the electrician didn't blink when I told him I wanted to add another 50 A circuit to my 200 A house. If I turn everything in my house on (6 pool pumps, 2 electric ovens, 1 dryer, 2 large central air conditioners, and my 14-50 EVSE), I can pull over 350 A at 240 V just in the major appliances. However, I've never seen my meter go above 25 kW. It helps that I charge after midnight and tend to run the A/C in the afternoons, but my point is that I have a lot of stuff that takes power, and I don't seem to be getting close to 200 A. I can't imagine needing 600 A unless you were thinking about putting in a bunch of HPWC for several Teslas.

    I imagine that Orlando doesn't need a whole lot of power in home electric heating? How big is your A/C? Unlike in San Jose where it cools off at night, in Orlando, you'll probably need to run your A/C while your EVs are being charged.

    Anyway, I was thinking that 200 A would be sufficient, but 300 A might be a nice safety.

    Regardless, I think "largest you can afford" seems dubious to me. If they're a billionaire and can afford 10,000 A, should they do that? If they can only afford 200 A but know they're installing 3 HPWCs, should they still do 200 A?

    I look at it this way: they should minimize expected cost. If there's a 50% chance that they'll need to later upgrade from 200 A to 300 A, but it would cost 3 times as much (including the cost of inconvenience) to do the upgrade later than to just do it now, they should get 300 A now. If there's a 10% chance that they'll need to later upgrade to 300 A, and the cost to do the upgrade later is only 3X, I'd go with 200 A now.
     
  12. jamieb

    jamieb Member

    Joined:
    Oct 26, 2013
    Messages:
    153
    Location:
    Sacramento
    Since you're at the design stage it may make sense (depending on your electric utility and their EV charging rates) to wire a sub-panel in the garage that runs off a separate time-of-use meter that your utility will install when they turn on your service. That way you'll qualify for the lowest rates. Here in Sacramento I get a rate of 6¢/kWH for off-peak charging, but this is possible only with a separate time-of-use meter. It's a carrot-and-stick deal - if you charge during peak hours of declared 'conservation days' when the grid is particularly stressed, the punitive rate is $3.50/kWH. Ouch. See: smud.org
     
  13. nwdiver

    nwdiver Active Member

    Joined:
    Feb 17, 2013
    Messages:
    2,402
    Location:
    United States
    You got that backwards... the saying I was taught in the Navy was "Volts hurt, Amps kill" That's how Tasers work... 100k volts / 0.00001A. Or think of a static shock... that can often be >10k volts but since the current is so low it doesn't cause injury.

    I think 200 amp is more than sufficient.
     
  14. miimura

    miimura Active Member

    Joined:
    Aug 21, 2013
    Messages:
    1,244
    Location:
    Los Altos, CA
    "Possible only with a separate time-of-use meter" is not technically correct. You can put your whole house on the same TOU plan that gives the EV Off-Peak discount. However, that opens you up to being charged a high peak price for things like A/C.

    The decision on whether to go with separate metering is very much dependent on your local situation. If your utility offers TOU Super-Off-Peak discounts for EVs there's a good chance that it's a good idea. However, if you are in an area that has solar net metering and your home is well situated for solar and you have relatively high electric rates, you should get solar and stay with one meter so that the solar can offset your vehicle charging usage. On the other hand, if you're in an area that has flat $0.11/kWh electricity, then none of this matters.
     
  15. evmile

    evmile Member

    Joined:
    Oct 16, 2011
    Messages:
    126
    Location:
    San Jose
    I upgraded from a 150 A to 400 A service. Each HPWC is a 100 A circuit so 400 A doesn't seem like very much if you have two Teslas charging.
     
  16. WarpedOne

    WarpedOne Supreme Premier

    Joined:
    Aug 17, 2006
    Messages:
    2,653
    Location:
    Slovenia, Europe
    Go for 300A, it's a sweet-spot.
    It is 50% more than 200A for 2k, another 2k only buys you another 33% more.
     
  17. Al Sherman

    Al Sherman It's about THIS car.

    Joined:
    Nov 29, 2012
    Messages:
    1,692
    Location:
    Batesville, IN
    Yes. Really. I'm amazed at how often us "old farts" agree on stuff like this. Stuff that seems obvious to us based on life experience I guess.
    Jerry can speak for himself but I think it's pretty obvious he didn't mean a billionaire should buy a 10,0000A service. Pretty sure he meant within the choices that the OP specified in the title of the thread.

    There's no complicated algorithm. If you're building a reasonably sized new house, get the 400 if the govt and PoCo weenies will allow it. No percentages, or games of chance. Just advice from a guy who's been to more than a few rodeos. :smile:
     
  18. brianman

    brianman Burrito Founder

    Joined:
    Nov 10, 2011
    Messages:
    15,487
    Two questions:
    1. You listed the differential but not the base cost. What is the cost of the 200A option (which will also allow us to understand the cost of the other options)?
    2. What is the ballpark overall cost of the house?

    These two answers will help us provide more useful recommendations and opinions.


    If, for example, the 200A option is $20 and the house is $5,000 then the 300A and 400A panels are definitely not worth it. ;)
     
  19. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,753
    Location:
    Texas
    The cost of a larger breaker panel is minimal compared to upgrading the breaker panel later. And I was assuming a somewhat average income. That said, the billionaire probably has a very large house and grounds with a lot of electrical equipment so a panel that seems ridiculously large to us might actually be in order. I doubt that Steve Jobs' house only as a 200 or 300W breaker panel.
     
  20. Solarguy

    Solarguy Member

    Joined:
    Nov 7, 2013
    Messages:
    119
    Location:
    Indialantic, Florida
    I also live in Central Florida and went through a similar tradeoff two years ago. My home was built in 1977 and originally fitted with one 200amp and one 100amp panel fed directly off the 200amp meter feed. Two years ago I did extensive renovations (added 1500 sq. ft.) bringing the living space to 3500 sq. ft. and the garage to 1400 sq. ft. The house is all electric: 2 four ton 19 SEER A/C's, whole house tankless water heater, pool pumps, irrigation pump, range, 2 refrigerators, ice maker, freezer, 10 ceiling fans, dryer, full size lift in the garage, 5hp table saw, 5hp air compressor and several other high power wood and metal working tools (hobbies).
    I also installed a 15.25KW solar system which provides us free electricity and pays us back on average $1500 a year for the excess power generated.
    The final decision was to go with a 400amp service and to add a second 42 slot 200amp panel in the expanded garage with a 100amp branch panel with critical circuits for generator back up (manual transfer). To do this the power company (Florida Power and Light) had to add an additional power pole and transformer on the street and run heavier gauge underground feeder cable to the new 400amp meter housing/pan. Thank goodness they picked up all those costs, I can not even begin to imagine how prohibitive it would have been. Many power companies will not cover these "upgrade" costs. So, when building new, specifying the larger feed to the meter initially is best IMO.
    Now that we have a Model X on order we are very glad we did all the above. We are currently gathering materials to install two HPWC's both @ 100amp for the MX and likely a Model E in the future :) One will be fed from the 200amp garage panel and the other from the 200amp house panel to balance the load in case both are to be used at the same time.
    We do have net metering here in Florida with a single rate of .12Kwh at present.
    My experience is that it is hard to anticipate your future needs but they are likely to be more than you currently think and that having the contingency available can be financially beneficial and maybe even psychologically comforting.
     

Share This Page