Which outlet to install at home?

Which outlet to install at home?

Expecting my new Roadster next week. I'm lucky in that the main breaker for my house is in the garage, which doesn't have any sheetrock, so installation will be quick and easy. I have some slots open in my Challenger brand circuit breaker box. I'm either going to install a 220v 30amp or 50amp line to charge the car. I'm in the US, btw.

My question is: what outlet type should I install for 30amp, and which for 50amp? My thinking is that I should install what I'm most likely to find on the road, so that I'm not buying an extra adapter.

I'm thinking for 30amp the answer is a regular dryer outlet. That way if I travel and visit friends, I could use their dryer outlet to recharge. Even here, however, I think there are variations, aren't there?

But, I don't know the most common 50amp outlet I'd encounter on the road. I assume it would be a mobile home/RV park, right? What are those and do Lowes/Home Depot style stores carry them?

Any comments or suggestions would be appreciated.

Douglas3 | 02/06/2011

Use a 50 amp, NEMA 14-50R plug. This is commonly used for stoves and, more importantly, RV campgrounds.

Douglas3 | 02/06/2011

By the way... some owners cut off the neutral pin on the 50 amp connector so it can go into either socket; it's not actually used by the Roadster. Then when plugging into a 30 amp socket they manually dial back the power using the touchscreen. Of course if you forget you'll blow the breaker.

Personally I bought both adapters.

dsm363 | 02/06/2011

I agree. Install a 50 amp, NEMA 14-50R plug. Make sure the electrician looks closely at the install instruction sheet from Tesla. Get the Universal Mobile Connector

Note that the plug is installed upside down from normal so the cord can hang down. You can also get the J1772 adapter so it's easier to travel. Make sure your Roadster has the latest firmware before it leaves (which it should) so you can use the adapter.

DHrivnak | 03/06/2011

I too would install a NEMA 14-50 plug and would run wiring for 70 maps (4 gage 4 wires) and a 70 amp breaker. That way IF you want to upgrade to J1772 you are ready. At a minimum I hear the new MC 240 can pull 40 amps so you want to size for that. You do not need more at home in my humble opinion but at some point you may want another electric car that uses J1772 and the wire is relative inexpensive for a short distance.

smorgasbord | 03/06/2011

Thanks. I just stopped by Lowe's about bought a 50 amp breaker, NEMA 14-50R outlet, 12' of 6 guage wire, etc.

The diagram shows the ground connector (it's half round) at the top - is that correct?

Also, from this picture:

It appears I should install the outlet fairly high so that the two "boxes" on the cord don't rest on the ground. Can anyone give me an idea of just how high I should install it? I don't yet have my car or UMC - my goal is to install the outlet so when I get the car I'm all set.


dsm363 | 04/06/2011

Yeah. The round plug is on the top. The Tesla diagram is correct on that sheet. Probably install it maybe 4 or 5 feet off the ground. Have fun!

rsdio | 06/06/2011

I installed my NEMA 14-50R right below the breaker box so that I did not need to bend any conduit. I have a few boxes stacked near the wall and the "box" sits nicely on a flat, level surface rather than hanging it's weight down from the receptacle.

You definitely want the 50 A version to minimize your charge time for those occasions when you're in a hurry. The HPC might be worth it if money is no object for you, but usually an overnight charge is all you'll ever need and the 50 A can handle a full charge in less than 7 hours.

dsm363 | 07/06/2011

The HPC is probably most useful if you'll have other Roadster owners visiting your house for a quick charge often. Most of the owners I've talked to with a HPC say they rarely charge at 70A. I'm sure it's nice to have but probably not necessary. Nice thing about the UMC is that you can take it with you if you want to charge at a campground or something.

jmollenkopf | 08/06/2011

Hello everyone. I placed and order for a Roadster Sport (Vin # 1364 - Yellow) and hope to have it by August. I have an HPC that is being installed in the garage and was wondering if any of you put in a power meter? I want to be able to track volts, amps, KWH and KW that I input into the car specifically and I am looking for a great unit to install along with the HPC. Any suggestions would be appreciated.

I am going nuts waiting for this car. Thanks in advance.

the bonnie | 08/06/2011

Congrats on on your purchase, jmollen! You're going to be very happy shortly :).

No need to install a power meter - you'll have the option on your touchscreen to review the charge info from the night before & are able to also look back at the last several charges.

Ask your customer service rep for an electronic copy of the user manual (you might be able to see it on your 'My Tesla' log in page, but not sure) - I think that has all the info and then you can decide if a power meter is still required.

rsdio | 10/06/2011

By the way, I meant to comment on Douglas' mention that owners are clipping the neutral to allow plugging the NEMA 14-50P into different receptacles. I strongly recommend against this! All of the other receptacles are rated for less than 50A, so it's a bad idea. Yes, you can manually dial down the charge rate, but depending upon human memory when it comes to 12000 Watts of power is probably not the best first choice.

The recommended practice would be to order the correct adaptor from Tesla Motors for your UMC, and then when you connect the adaptor it will automatically your Roadster to charge at the right amperage. Yes, it costs a little more, but you only have to buy it once. Plus, you won't have any ugly-looking stubs on your plug.

smorgasbord | 14/06/2011

OK, so this is my install:

The outlet centerline is about 26" off the floor. The outlet is mounted with the half-round ground pin at the top (which is NOT considered upsidedown, btw). The cord hook was from Lowe's and cost about $8.

rsdio | 15/06/2011

That looks great!

I had to install my NEMA 14-50 the other way at first, due to limited space for bending the 4-gauge wire, but I went back and reinstalled it the way you have it. It's way more convenient when the NEMA 14-50 plug wire is oriented towards the bottom rather than the top.

The receptacle cover is a nice touch. The only thing I would suggest is a wooden platform or small table for the "box" - since I assume that is cement on the floor below. I suggest this only to avoid scratching the $1,500 UMC enclosure. Also, there might be less bending in the cable.

smorgasbord | 15/06/2011

4 gauge wire? You must have a long run because 6 gauge is typically enough for 50amps, unless you've got more than a 100' run.

I park just a few feet from this wall, so I only have to unwind 1 or 2 of the loops, meaning the box is always suspended just where you see it now.

rsdio | 19/06/2011

This was my first 220 V installation. Because everyone talked about "50 A" charging, I assumed that they meant the charging system actually draws a full 50 A, literally. I was worried that running a 50 A charger with a 50 A amp would just make it trip constantly. Thus, I got a 60 A breaker and 70 A wire (in 4 separate runs). That's the only reason I started with 4 gauge wire. I was quite surprised when my Roadster showed only a mere 40 A on the VMS screen.

Surprisingly enough, the local Lowes hardware store has a certified electrician working the floor, and he informed me that the code specifies that a circuit should not carry more than 80% of its rating. I kinda felt short-changed because people weren't really making it clear that you only get 40 A. But, after understanding all of this, I downgraded to a 50 A breaker and 55 A wire. Not sure what the gauge is, and it's still stiff, but not nearly as challenging as the 4-gauge 70 A wire.

So, no, I don't have a long run. In fact, it's less than 1 foot from my fuse box. It was all a misunderstanding, but thankfully not an unsafe misunderstanding. Someone on the forum did point out that the NEMA 14-50 is not rated for 60 A, and thus my original breaker could have allowed an unsafe condition, but everything is to code now.

rsdio | 19/06/2011

... oh, about the box: I just worry that flexing the cable close to the box might cause problems in the long term. My box sits stationary, and the cable does not flex anywhere near it. Instead, the long run of cable is what gets coiled and uncoiled on a daily basis. I suppose it's a little silly to worry about flexing such a ridiculously thick cable, but everything wears out eventually.

PrairieElectric | 05/07/2011

Have any of the Tesla owners needed/wanted to upgrade their home electrical service beyond 100 amps? Does anyone know what Tesla's perspective on this is?

Douglas3 | 05/07/2011

Yes, my house panel was 100 amps and I had it upgraded to 200 amps to support the HPC.

In retrospect I probably needn't have bothered. I have no pressing need for 70 amp charging at home, and in fact usually charge at 40A. I use 70 amps once every few months, and even then just for convenience, e.g. topping up to Range mode at the last minute. A NEMA 14-50 plug and the UMC would have been quite sufficient.

rxdxt | 14/10/2011

Hey all. It's Titus here (producer of Who Killed the Electric Car?) we've settled into our house in San Francisco and I need to get 220 power installed and likely a NEMA 14-50 Plug (and something for the wife's Leaf as well, but that's another story.)

My question is simple:
- Approximately how much should this cost? (there's NO 220 power in the house and only 100 amps in the house from the street - I know it's a rental so no major work wanting done)
- Anyone have a good FAST electrician in the Bay Area?


Brian H | 15/10/2011

Good, fast, cheap. Pick two.

the bonnie | 15/10/2011

Hi Titus -

I live north of you (30 miles past Sac) & paid $400 for a NEMA 14-50 outlet to be put in my garage so that I could charge my Roadster. That included a new breaker switch and installing the line. I'd recommend an electrician, but you're not close enough :).

I saw ROTEC a few weeks ago at a screening in Palo Alto - perfect timing, right in the middle of the Model S weekend. Great job on the film! Amazing moment captured with Elon and Bob Lutz looking at Nissan's offering.

Hope you find a good electrician - will the landlord at least bring 220 into the house? Then maybe you could just pay the extra to have an outlet in the garage.

Best of luck,

Delete Me Knapp | 25/10/2011

I second Douglas3: I also put in an HPC and upgraded the electrical. I haven't really benefited from the HPC and would have been fine with the UMC . I chose the HPC since it wasnt much more than a UMC, which i doubted i'd use on the road. ButI ended up later buying the UMC for work as well. But I have had a few other Roadsters stop by who appreciated the 70 amps at least.

We also upgraded the 100amp house service but this was necessary for the solar system we put in at the same time.

BTW, I'm putting in a NEMA 14-50 at my work's second office. Is it wise and or necessary to put in an on/off switch? Any risk plugging in or unplugging from a live outlet? Of course I'd stop charging first. The electrician at our first office put in such a switch and it is nice to know I'm not going to accidentally zap myself.

Douglas3 | 08/11/2011

Shouldn't be a problem plugging/unplugging a NEMA 14-50. Just don't wrap your fingers around the plug!

Fortunately 240V in North America is two-phase, so each hot pin is only 120V. Unless you manage to get connected to BOTH hots you're not going to get any more of a zap than a 120V plug.

Hypermiler | 20/11/2011

At Douglas3: thank you for the interesting discussion. One small addition: each individual phase in the US is 120 V vs ground.

Three phases combined are 220V vs ground because of the 120 deg interval between each sinus curve. In Europe, this is 220V in each phase, combining to 360 deg overall.

Amperage of course adds straight.

Hypermiler | 20/11/2011

PS: 3 Phase US is 240, sorry. More in depth info on 3 phase with 4 wire, 2 phase phase-to-phase and other possible situations in residential US installations here:

Brian H | 24/11/2011

gotta watch out for those hook-nosed sinus curves!


DHrivnak | 01/12/2011

I am quite certain you have 220V to the house as every house I have seen has that as it is needed for a range, hot water heater, hot tub or central AC.

If you have room to install a double breaker it should not be a bid deal. I added a NEMA 14-50 in my garage and had 30' run of wire and I installed it for about $75 for all the parts and while not an electrician it only took me about 2 hours.

Brian H | 01/12/2011

A neighbour across the lane mentioned his wife hangs clothes to dry because his (older) place isn't wired for 220. All she's got are small 120V washer and dryer, which can handle only very small loads. This is in the middle of a residential area of a large city.

jbunn | 12/12/2011

Because the older houses in sf were plumbed for gas lighting, many applianes are gas. He truly may not have 220. Seen some appartments with only two 15 amp circuts, knob and tube wiring, and even using the old gas lines for conduit. 19th century technology...

ncn | 15/12/2011

Getting the 220 into the house could be very expensive, or it might be quite cheap. You'll have to check with the local electric company (who will have their own rules) as well as with local electricians.... and with the landlord, of course.

Once you've done that, the internal wiring will be in the range others have stated.

jordanthompson | 15/05/2012

Has anyone mounted the outlet in the middle of the garage ceiling (so either side has access to it?) I realize if you are parking on the left side, the wire will go across the back of the car, but I am thinking a bungee cord would keep it clear.

debbso | 13/05/2013

Has anyone run into a poblem getting the 30 amp plug into the garage. our breaker box is on the other side of the house. the only way to run wiring is to trench up the stone driveway, any suggestions?

Brian H | 13/05/2013

The other side of the house?