Just signed a contract for a new home, going to finalize the options next week. I'm not sure how flexible the builder is with their options but ideally I'd like to ensure our new house is ready for our current S75 and future proofed for a potential second Tesla. Ideally I'd like to get it wired with 2 14-50 outlets but I don't know how well (if at all) that'd work with 200 amp service. Getting 2 HPWCs might be better but that's probably not something the builder is interested in wiring up and besides, after paying for this house I don't think a second Tesla will be in the cards anytime soon. I don't know if higher amp service is an option, but I'll ask. Anything else I should think about?
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New construction home...what to request from the builder re: electrical
- Thread starter Graveworks
- Start date
For maximum convenience and flexibility, I would have them put a subpanel in your garage that you can use for the cars and it will make any kind of expansion easier than home runs back to the main panel (and it will save physical breaker space as well). Not sure how big of a subpanel you can go, but 125 amps would certainly give you some futureproofing...
Then you can install two NEMA 14-50 receptacles on separate circuits. If capacity is an issue, then you can buy the new HPWC units that can share power...Either way, in the building stage of a new home it is definitely the easiest time to add what you need...
Any way you can go higher than 200 amps on the main panel? That will also provide you with some futureproofing....
Then you can install two NEMA 14-50 receptacles on separate circuits. If capacity is an issue, then you can buy the new HPWC units that can share power...Either way, in the building stage of a new home it is definitely the easiest time to add what you need...
Any way you can go higher than 200 amps on the main panel? That will also provide you with some futureproofing....
Thanks, probably a good idea - spoke to one of the neighbors with a P100D and his panel was in the basement, had to run quite a line out to the garage. Not sure yet where the panel is in our floor plan but I'm guessing something similar, subpanel would help if they can do it.
Yeah, a panel in the garage during construction is a lot cheaper. See the excellent FAQ in my sig for tons more info. One 100 Amp circuit can run two HPWCs sharing the power, which should be enough for any two Tesla. 
I built 2 years ago (just owned a Leaf and a Plug-in Prius then, but wanted to plan for two Teslas in the future). I put a 150A panel in the garage, with 300A service to the house. One 50A 14-50 outlet and one 40A hardwired J1772 (with wiring that will support 50A in the future). Perfect for us! Other great thing with the panel right there is I can very easily change things as the tech changes (or charging port locations change!)
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I just did this and went with a 125A sub panel that feeds a 14-50 outlet on one side of the garage and a 70A line to the other. The 70 is currently capped off and ready for a HPWC when the Model 3 arrives. Thia will let me charge two cars overnight at 40A or one more quickly if needed. All told, it added about $1200 to the price of the house.
The other option was a 200A sub panel that fed a 100A line to each side so I would have the capability of two full power HWPC simultaneously. That was much more expensive b/c it required extra hardware. I thought it was probably overkill anyway.
The other option was a 200A sub panel that fed a 100A line to each side so I would have the capability of two full power HWPC simultaneously. That was much more expensive b/c it required extra hardware. I thought it was probably overkill anyway.
Here is Tesla's installation guide for NEMA 14-50:
https://www.tesla.com/sites/default/files/downloads/US/universalmobileconnector_nema_14-50.pdf
https://www.tesla.com/sites/default/files/downloads/US/universalmobileconnector_nema_14-50.pdf
All of the electrical advice has been covered, but here's a tip on the size of the garage. If it's listed as a "2-car garage", often times you have trouble parking 2 cars in the garage due to the location of where the steps from the garage into the house end up. "2.5 car garage" should be safe, and will give you extra junk space. If 2.5 car garage is not an option then make sure to carefully review the location of any garage stairs. If it's only drawn as 1-2 steps on the drawing it may end up much different, as often the final grade of the house and garage are different than the drawings anticipate - and the only remedy is more steps that end up jutting out further into the garage and blocking your parking spot.
For our new house, we had the builder install an extra 100A circuit. On one side of the garage, we ran a short 100A line to an HPWC. On the other side, we ran a 50A line to a 14-50 outlet.
When we only had our S P85 (with dual chargers), we ran the HPWC at 80A.
Now that we've added an S 100D, we've moved the S P85 to the 14-50 outlet and lowered its charging to 32A (which is fast enough for a full overnight charge). And for the 100D (with the 48A charger) we run the HPWC at 48A, and can fully recharge the 100D overnight.
In this configuration - both cars are able to fully charge overnight - and can share the 100A circuit.
Having two HPWC's could allow them to coordinate and more efficiently share the power - but that's probably not needed for most people...
When we only had our S P85 (with dual chargers), we ran the HPWC at 80A.
Now that we've added an S 100D, we've moved the S P85 to the 14-50 outlet and lowered its charging to 32A (which is fast enough for a full overnight charge). And for the 100D (with the 48A charger) we run the HPWC at 48A, and can fully recharge the 100D overnight.
In this configuration - both cars are able to fully charge overnight - and can share the 100A circuit.
Having two HPWC's could allow them to coordinate and more efficiently share the power - but that's probably not needed for most people...
SDRick
Active Member
[QUOTE="If 2.5 car garage is not an option then make sure to carefully review the location of any garage stairs. If it's only drawn as 1-2 steps on the drawing it may end up much different, as often the final grade of the house and garage are different than the drawings anticipate - and the only remedy is more steps that end up jutting out further into the garage and blocking your parking spot.[/QUOTE]
I would prefer no steps from the garage into the house as a goal when building new
I would prefer no steps from the garage into the house as a goal when building new
When I had my house built 5 years ago I didn't have any plug-in vehicles, but I knew it was an eventuality. I have one big garage door for the two car garage. I had the electrician put a 14-50 socket on each side wall. The only thing I would do different is to put the one on the right side wall closer to the garage door. They were both put about where the B-pillar is when a car is parked.
Standard chargers are getting smaller, not bigger. Tesla started out Model S with up to 80 amp charging. Now the highest is 72 amps on S & X with 48 amps standard and Model 3 is 32 amps or 40 amps. The need to have more than a 50 amp circuit per car is vanishingly small.
Standard chargers are getting smaller, not bigger. Tesla started out Model S with up to 80 amp charging. Now the highest is 72 amps on S & X with 48 amps standard and Model 3 is 32 amps or 40 amps. The need to have more than a 50 amp circuit per car is vanishingly small.
SDRick
Active Member
If I had a chance to build my garage again I would definitely design enough room between cars that the doors can be open fully without worrying about hitting another car!
Yes, I think most everyone would. But good luck trying to get a builder to commit to that upfront when the garage is a concrete slab and the foundation of your house is a basement or crawlspace. They very rarely line up nicely, and no builder wants to spend to increase the grade of where the garage slab will be poured.
ddimit
Member
if your building new I would look at the cost difference to upgrade to 300 amp service feed. Its going to be way cheaper to do it now than have to deal with it at some future date.
SDRick
Active Member
I would not think it's rocket science. If the plan shows a 3" difference between the garage floor and the main floor, wouldn't the builder build according to the plan specifications?
Did they go shoot the grades of your land to figure that out? Unlikely. Did they already dig a hole and confirm they like how the house is sitting? Surely not. Our builder raised our house a foot the day they dug the foundation once they figured what the drainage was going to be like. Our proposed 2 steps in the garage went to 4. Trust nothing until it's done.
SDRick
Active Member
I would expect the builder to do what ever is necessary for the house to come out per plan. If that means they have to take some measurements so I don't have any steps in my garage to worry about, I guess they better take the measurements.
This will not happen. As it is code to have at least 4" garage slab lower. This is to avoid ice poison from running cars entering the house. Maybe you can get the local enforcement to allow an exception. But highly unlikely.
SDRick
Active Member
A few inches difference in slab grade per code is no big deal. Having multiple steps inside the garage (unless desired) can be avoided with proper planning and construction.
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