Builder installing 220 line to charge Tesla

[RonB]

I have paid for installation of a 220 line as my new home is under construction. I have no electrical knowledge but have the following questions for peace of mind.

My existing house has a 220 line in the garage with 50amp breakers and I use the mobile connector for my M3 which works great.

I was informed the builder will run a 220 line from the breaker box in the garage to a 220 outlet short distance is all I need. Whatever "plug" they install may not fit the Tesla connector and they only install 20amp breakers.

After closing of course I can make changes. Do you think all I have to do is install the correct 220 wall plug to accept the Tesla mobile connector and then replace the 20amp to 50amp breakers?

Hope the above makes sense.

 

[Outpost53]

If they disagree it will be a pain to rip apart a new house after your closing. If they won't run #6 have them install a conduit so you don't have to rip apart the walls later. At least 3/4" emt or 1" pvc. If it's in conduit you can get away with #8 for a plug or if doing a wall charger you will need #6. A sub panel would be even better.

 

[Silicon Desert]

Technically you mean 240vac.
One problem I forsee is that if they don't run large enough wires to support higher amperage than what they are doing for a 20 amp breaker then you may have to pull through heavier wires later. And of course your panel will need to be able to handle putting in a larger breaker depending on how much load is already on the panel for other things on the property.

 

[355rockit]

NEMA 14-50 is the standard for 240V 50A outlets which is what you have in your current house. If the builder is running a 240V line to the garage, it should be NEMA 14-50 outlet or won't be up to code (given 50A). The wiring as well has to be a certain gauge to be up to code, so if the builder is only putting in a 20A breaker, the wiring may not be up to code for 50A if they didn't do the correct gauge wire for 50A.

 

[EVDRVN]

Be sure they run wire for a 50A circuit or whatever the max they can up to 50A. Even if they use 20A breakers it's fine then you are covered if you can upgrade the breakers. FYI its 240V not 220V there has been no 220V since the turn of the century in residential homes with one small exception.

 

[ElectricIAC]

I have paid for installation of a 220 line as my new home is under construction. I have no electrical knowledge but have the following questions for peace of mind.

My existing house has a 220 line in the garage with 50amp breakers and I use the mobile connector for my M3 which works great.

I was informed the builder will run a 220 line from the breaker box in the garage to a 220 outlet short distance is all I need. Whatever "plug" they install may not fit the Tesla connector and they only install 20amp breakers.

After closing of course I can make changes. Do you think all I have to do is install the correct 220 wall plug to accept the Tesla mobile connector and then replace the 20amp to 50amp breakers?

Hope the above makes sense.

Wiring has to be correct to use a big breaker.

 

[paulk]

60 amp wiring would be better, then you could charge a car at max if you ever installed a wall connector. You could have a 50 amp breaker and receptacle, but in the future upgrade easily to support a wall connector.
if you want real future-proofing, install a 100 amp sub panel in the garage.

 

[roblab]

You need wire labeled at least 6-3 with ground, on a 50 amp breaker, with no other loads on it. I have only my one dedicated outlet for charging, and another dedicated outlet for charging my wife's car. I can't imagine why your electrician feels he can't do what you asked. Of course there may be issues with other circuits and worry about overloading, but that's why you hired an electrician. Sounds to me like you might need to look around for someone who knows how to wire a house.

Yes, you might want a 100 amp sub-panel in the garage. Any more, garages are wired with 220, and the push will be to do this more often as we get more and more EVs on the road. Charging an EV on a 110 outlet could take all day.

 

[EfficientWatts]

It doesn't make sense to me that they only install 20amp breakers. A dryer outlet uses 30amp breakers. Electric stove outlets use at least a 40amp breaker. Seems like its more of a wiring issue and they don't want to route the thicker cable to the garage.

I would be concerned if they say you can upgrade it afterwards. Unless they're doing something I don't know any wiring that would fit both in a nema 6-20 outlet and a nema 14-50 outlet.

If the main electrical panel is in the garage already and they continue to refuse to install a real outlet into the garage I would rather have a 3rd party come in and install it. If its in the backyard then yea it may be more tricky.

 

[KenC]

Yep, wire gauge is the question. For a 20amp service, it might be 10gauge. For a 50amp, you would need 6gauge. I converted my outlet from a NEMA 6-20 to a NEMA 14-50, and the differences are breakers, wire gauge, and outlet receptacle.

 

[Gauss Guzzler]

Basically what they're telling you is that they wire the house with 12 AWG. So if you want it to be 120V or 240V that's fine, it's still going to be 20A either way. You will not be able to "upgrade the breaker", it's illogical and in many cases illegal to install oversized wire so that absolutely will never be an option.

A 20A/240V outlet is perfectly adequate to charge the car, but just barely. Consider asking them to quote some upgrade options:

• Keep the 20A outlet but also add a 60A 2-conductor circuit (ending in a closed box with no outlet) that someone will later connect to a wall charger.
• Keep the 20A outlet but also add a 50A commercial grade outlet (not a 50A residential grade outlet) This will be considerably more expensive than the 60A circuit because it requires a GFCI breaker plus the pricey outlet and a 3rd conductor for the modern standard "14-50R" outlet.
• A second 20A outlet assuming it's a 2 car garage.

Note that any work they do "for the purposes of EV charging" qualify for a 30% federal tax credit, including the first 20A outlet. So as long as they can itemize these circuits you'll get back 1/3 of the cost. This also brings the cost of the wall charger down from $550 to $385.

 

[Sr Geek]

I just installed a 60A breaker into 200' 6/3+G to the Tesla wall charger. The wall charger will draw 48A max for the fastest charging available today. You are not getting anything relative to vehicle charging for your money using 20A breakers. Lots of good advice above. I'd get another electrition involved if the builder will not give you what you need. Oh, also the Tesla wall charger has a built-in GFCI, don't double up with them, that will not work.

You can save some money and live with reduced charge time by installing a 50A dryer circuit. All of the information you need is on the Tesla website.

 

[RonB]

Thanks to all of you for the good information. I will explain to the builder I want 6/3 gauge wire, a heavy duty Nema 14-50 wall connector and two 50amp
breakers. If they disagree, I will have an electrician install everything after closing. Again, thanks for your replies as I now know what I need.

 

[EVRider-FL]

60 amp wiring would be better, then you could charge a car at max if you ever installed a wall connector. You could have a 50 amp breaker and receptacle, but in the future upgrade easily to support a wall connector.
if you want real future-proofing, install a 100 amp sub panel in the garage.

Only some Model 3’s can charge at 48 amps, so upgrading to 60 might not help the OP with their current car. Also, as I’ve learned in my new home with solar panels and Powerwalls, sometimes you don’t want to charge at your car’s maximum rate if you‘re not in a hurry. In my old house my Model S could charge at 72 amps, but I decided to use a 60 amp circuit in my new house, since charging at 48 amps is fast enough.

 

[nstig8]

Note that any work they do "for the purposes of EV charging" qualify for a 30% federal tax credit, including the first 20A outlet. So as long as they can itemize these circuits you'll get back 1/3 of the cost. This also brings the cost of the wall charger down from $550 to $385.

As far as I know this credit has only been extended through the end of 2021. Any work done after that will not qualify. Also only up to $1000.

 

[rpiotro]

I just installed a 60A breaker into 200' 6/3+G to the Tesla wall charger. The wall charger will draw 48A max for the fastest charging available today. You are not getting anything relative to vehicle charging for your money using 20A breakers. Lots of good advice above. I'd get another electrition involved if the builder will not give you what you need. Oh, also the Tesla wall charger has a built-in GFCI, don't double up with them, that will not work.

You can save some money and live with reduced charge time by installing a 50A dryer circuit. All of the information you need is on the Tesla website.

I have a 40 amp circuit for a 32 amp (7.7KW) charge rate. I can't imagine any Tesla not being able to be fully charged overnight while sleeping.

 

[RonB]

Outpost53, good backup plan using the conduit, thanks for the idea.

 

[Gasaraki]

I have paid for installation of a 220 line as my new home is under construction. I have no electrical knowledge but have the following questions for peace of mind.

My existing house has a 220 line in the garage with 50amp breakers and I use the mobile connector for my M3 which works great.

I was informed the builder will run a 220 line from the breaker box in the garage to a 220 outlet short distance is all I need. Whatever "plug" they install may not fit the Tesla connector and they only install 20amp breakers.

After closing of course I can make changes. Do you think all I have to do is install the correct 220 wall plug to accept the Tesla mobile connector and then replace the 20amp to 50amp breakers?

Hope the above makes sense.

It's 240V not 220. Also I think you mean you have a 200A circuit going in to your new home.

Most likely no. If they are installing a 240V plug but only putting a 20A breaker for it, they will most likely not be using a good enough wire (gauge) to support the 50A breaker, 32A charge level of the mobile connector. You will need to replace the wire to a lower gauge wire so your house won't burn down.