Standard 110v (?) Outlet to 240V outlet

[Cashoverass]

I swearrrr I searched the forums and on google (for like 20 minutes) and surprisingly didn't see a thread or an answer to what I thought would be the most frequently asked question.

In my garage I have a standard outlet (I guess it's a 110 v outlet) that's in the perfect place. I never use it but it's the perfect height and distance to where I park.

I'd like to "change" that outlet to the 240v outlet I'll need for the model S. Is that a better/easier solution than having a whole new 240v outlet installed?

Any tips for having this done? I'm usually a pretty good DIYer when it comes to car stuff but messing with my home electricity makes me nervous. is this worth turning off the breaker and giving it a shot or is this a more complicated project that I should save for the professionals.

 

[ohmslaw]

I swearrrr I searched the forums and on google (for like 20 minutes) and surprisingly didn't see a thread or an answer to what I thought would be the most frequently asked question.

In my garage I have a standard outlet (I guess it's a 110 v outlet) that's in the perfect place. I never use it but it's the perfect height and distance to where I park.

I'd like to "change" that outlet to the 240v outlet I'll need for the model S. Is that a better/easier solution than having a whole new 240v outlet installed?

Any tips for having this done? I'm usually a pretty good DIYer when it comes to car stuff but messing with my home electricity makes me nervous. is this worth turning off the breaker and giving it a shot or is this a more complicated project that I should save for the professionals.

You probably need to beef up your breaker and wiring. You don't gain much due to the existing outlet being there.

 

[jerry33]

The breaker, wiring, and receptacle are all different, so the only thing you gain is the hole in the wall. And you'll likely want a 120V outlet near the car anyway for various items.

 

[Dave EV]

but messing with my home electricity makes me nervous. is this worth turning off the breaker and giving it a shot or is this a more complicated project that I should save for the professionals.

tl;dr; Contact an electrician and have them install a dedicated NEMA 14-50.

Long version:

Sounds like you might want to leave this to a pro, but it may be possible with a lot of caveats.

At best you might be able to upgrade this to a 2-pole 240V outlet rated for 15-20A by swapping out the outlet for a 240V outlet and the single-pole breaker for a double-pole breaker. Whether you could do 15A or 20A would depend on the wire size - if 14GA you'd be limited to 15A, if 20A you'd be limited to 20A. To see what these plugs look like search for NEMA 6-15 or 6-20. If you have 12GA wire I'd really recommend a L6-20 receptacle - much more secure than a 6-20 outlet.

The biggest issue here would be making sure that no other outlets are still wired up to the same circuit - obviously you don't want 240V flowing to appliances that are only expected 120V! If you had additional outlets the safest thing to do would be to pull the outlets and block them off.

The next issue is that you need a suitable adapter - Tesla doesn't make one so you'll have to make or acquire your own - and you'll have to make sure you dial down the charge current accordingly to either 12 or 16A for a 15A / 20A outlet respectively.

So lots of caveats, but it can be done safely if you know what you are doing. If you don't, contact an electrician and have them hook you up.

 

[Cosmacelf]

Yeah ... chances are the 120V receptacle is also connected to another receptacle, or garage lighting, etc. Get an electrician to install a new nema 14-50...

 

[FlasherZ]

If it's a single-gang box, a 14-50's wiring will violate fill rules. You need to have a larger box (2-gang or square box).

 

[neroden]

I swearrrr I searched the forums and on google (for like 20 minutes) and surprisingly didn't see a thread or an answer to what I thought would be the most frequently asked question.

In my garage I have a standard outlet (I guess it's a 110 v outlet) that's in the perfect place. I never use it but it's the perfect height and distance to where I park.

I'd like to "change" that outlet to the 240v outlet I'll need for the model S. Is that a better/easier solution than having a whole new 240v outlet installed?

Answer which nobody else mentioned: it depends on the way your house is constructed.

You have to completely replace the wiring from the breaker box to the outlet. If your wiring is in *conduit*, then yes, it is easier to rewire the outlet than it is to install a new one. Conduit is commonly used in commercial buildings and in masonry buildings. Electricians can pull new wires through old conduit without cutting any holes. (My parents had an entire house rewired with basically no cutting because the entire house had been built with solid metal conduit. New wire pulled four stories through existing conduit.)

If you have a wood-frame house, the wiring is unlikely to be in conduit. If the wiring isn't in conduit, then you can't replace the wiring without cutting holes in the walls, so it's just as easy to install a completely separate outlet.

Hire an electrician.

By the way, if you want to future-proof your house so that it's easy to install lots of additional electrical wiring later? Put in conduit.

 

[brianstorms]

Is it possible to run a 120V line *and* a 240V line through the same conduit, or do there have to be two conduits if one opts to have two outlets in the garage, a 120 for vacuuming and other general stuff and a dedicated 240 for charging the car?

 

[mknox]

I almost hate mentioning this because it is a temporary solution at my house. I had a dedicated 20 amp, 120 volt circuit fed to my garage with #12 wire for a hot tub I no longer use. I replaced the 120v single pole breaker with a dual pole 240 volt breaker, marked both wires black with electrical tape and use it to feed my UMC. I set the car to charge at 16 amps (80% of the circuit rating) and get 11 MPH of Rated Range. I need to get my buddy with his big drill to help me drill through the block wall and into my basement to run the proper 3#6 to my NEMA 14-50.

 

[Cosmacelf]

@mknox - I know you know this, but I want to put it out there. Yes you can convert a dedicated 120V 20A receptacle to a 240V, 20A receptacle (by connecting the white neutral to the other phase and using a 2 pole 20A breaker), but using a NEMA 14-50 as the receptacle is not a good idea. You could die of a heart attack tomorrow, and the new house owners would look at the receptacle and say, cool, a 50A 240V plug! Make it really temporary and fix it soon! Alternatively, terminate it in a NEMA 6-20 receptacle so at least then it'll be code (then make a NEMA 6-20 to NEMA 14-50 adapter).

 

[shady]

Something else to consider.
When Solar City did my install, they told me they needed to pull permits

 

[FlasherZ]

Is it possible to run a 120V line *and* a 240V line through the same conduit, or do there have to be two conduits if one opts to have two outlets in the garage, a 120 for vacuuming and other general stuff and a dedicated 240 for charging the car?

Yes, but because there are more than 3 current-carrying conductors, you'll have to derate them, meaning that you'll have to use larger wiring than is normal.

- - - Updated - - -

I almost hate mentioning this because it is a temporary solution at my house. I had a dedicated 20 amp, 120 volt circuit fed to my garage with #12 wire for a hot tub I no longer use. I replaced the 120v single pole breaker with a dual pole 240 volt breaker, marked both wires black with electrical tape and use it to feed my UMC. I set the car to charge at 16 amps (80% of the circuit rating) and get 11 MPH of Rated Range. I need to get my buddy with his big drill to help me drill through the block wall and into my basement to run the proper 3#6 to my NEMA 14-50.

I'm assuming you replaced the breaker with a 20A dual-pole breaker. Just want to make it explicit that you didn't do a bad, bad thing and put a 50A breaker in... Other readers need to know this critical element.

 

[neroden]

Yes, but because there are more than 3 current-carrying conductors, you'll have to derate them, meaning that you'll have to use larger wiring than is normal.

Good grief, where is this from? This doesn't sound right at all. Top-notch union electricians have pulled dozens of current-carrying conductors through a single solid metal or even plastic conduit, with no "derating". (Each set of conductors was individually fully insulated/wrapped within the conduit.)

You have to have a sufficiently large-diameter conduit, mind you.

---
It's usually not worth putting conduit in in "hollow-wall" houses. I've done it in a few areas where the utilities in the wall are so thick that there's a danger of cutting into other utilities if you try to feed more wires through the wall without a conduit.

 

[mknox]

I'm assuming you replaced the breaker with a 20A dual-pole breaker. Just want to make it explicit that you didn't do a bad, bad thing and put a 50A breaker in... Other readers need to know this critical element.

Yep, a brand new 20 A dual-pole breaker and labeled the outlet as such and yeah, I know it's not code, hence my "I almost hate mentioning this" :redface: I hope to have the proper #6 wire and 50 amp breaker in this month.

 

[FlasherZ]

Good grief, where is this from? This doesn't sound right at all. Top-notch union electricians have pulled dozens of current-carrying conductors through a single solid metal or even plastic conduit, with no "derating". (Each set of conductors was individually fully insulated/wrapped within the conduit.)

NEC table 310.15(B)(3)(a) "More Than Three Current-Carrying Conductors in a Raceway or Cable." This applies to the ampacity rating of conductors and is required for heat dissipation. There are also conduit fill rules, table 1 of chapter 9, which states the maximum amount of space occupied by ALL conductors.

The good news is that if you use THHN AWG 12 for the 120V/20A and THHN AWG 6 for the 240V/50A in a single raceway, the conductors meet the de-rated values (AWG 12 = 24A, AWG 6 = 60A), unless you need further temperature derating. You need to make sure you don't violate conduit size rules though.

It's usually not worth putting conduit in in "hollow-wall" houses. I've done it in a few areas where the utilities in the wall are so thick that there's a danger of cutting into other utilities if you try to feed more wires through the wall without a conduit.

Chicago requires you use conduit.

 

[scaesare]

Good grief, where is this from? This doesn't sound right at all. Top-notch union electricians have pulled dozens of current-carrying conductors through a single solid metal or even plastic conduit, with no "derating". (Each set of conductors was individually fully insulated/wrapped within the conduit.)

You have to have a sufficiently large-diameter conduit, mind you.
.

FlasherZ is correct...this is code everywhere I'm aware of...

 

[Dave EV]

Chicago requires you use conduit.

You can't use romex?

Cerrowire 125 ft. 6/3 NM-B Indoor Residential Electrical Wire-147-4203D at The Home Depot

 

[FlasherZ]

You can't use romex?

Cerrowire 125 ft. 6/3 NM-B Indoor Residential Electrical Wire-147-4203D at The Home Depot

In Chicago proper and some of its suburbs, it is required that you use conduit and Romex is outlawed. It's a union-sponsored regulation to force homeowners to use professional union labor -- erm, I mean, they believe it is "unsafe" to use bare Romex in walls...

(To be fair, Chicago does have a much lower rate of electrical fires; an all-EMT system is nice, but INCREDIBLY expensive compared to NM-B or NMD-90. I use NM cable in my own home and am satisfied with its safety.)

 

[Cashoverass]

Thanks guys! I have more questions. I've found a tonnnnn of posts about amperage but I can't find one that talks about an ideal amperage. If I'm only getting a 60kwh (limited to a 40) without the twin chargers, is there a max amperage that's either dangerous for the car or just pointless after a certain number of amps? or the more amps the better always.

I see the official tesla chariging instructions says over 15. But it seems 40 seems ideal in the research I've found so far.

I got a quote for 350 but they said it'd be cheaper if the amperage is less than 40. Is that weird? Is it normal that the price would change based on amperage?

Thanks!

 

[markb1]

Thanks guys! I have more questions. I've found a tonnnnn of posts about amperage but I can't find one that talks about an ideal amperage. If I'm only getting a 60kwh (limited to a 40) without the twin chargers, is there a max amperage that's either dangerous for the car or just pointless after a certain number of amps? or the more amps the better always.

I see the official tesla chariging instructions says over 15. But it seems 40 seems ideal in the research I've found so far.

I got a quote for 350 but they said it'd be cheaper if the amperage is less than 40. Is that weird? Is it normal that the price would change based on amperage?

Thanks!

You will probably want a NEMA 14-50 receptacle, because the car comes with everything you need to plug into that. This will require a 50 amp circuit. (No more, no less.) The car will only draw 40 amps over this, because that's what's allowed for a continuous load on a 50 amp circuit.

You can print this out and give it to your electrician:

http://www.teslamotors.com/sites/default/files/downloads/universalmobileconnector_nema_14-50.pdf