Charging Requirement and Options

[brkaus]

One last question: If I do the 120-to-240 upgrade and then use the UMC, as Uncle Paul suggests, would I be able to use that same 240 outlet if I decide later to buy a wall connector, or would I have to install a brand new electrical line to run to the wall connector? Thanks.

The Wall Connector is adjustable. You can set it based on your wiring and breaker size. It can replace most 240V outlets. It requires Hot-Hot-Ground. No neutral.

If you want to use it at higher amps, it would need better wiring of course. For a Model 3, I would suggest you ensure the wiring is setup to handle 60A. When you want to put in the WC, you wire it in and replace the breaker.

 

[eprosenx]

One last question: If I do the 120-to-240 upgrade and then use the UMC, as Uncle Paul suggests, would I be able to use that same 240 outlet if I decide later to buy a wall connector, or would I have to install a brand new electrical line to run to the wall connector? Thanks.

Yes, you could use that wiring for a Wall Connector (assuming already that it is dedicated just for that single receptacle), but it would be kind of a waste of a Wall Connector. 20a is not a ton of juice for something that can handle up to 100a.

Absolutely doable, but I would normally recommend running a new line if you are going to spend the money on a Wall Connector anyway.

 

[Brenkj]

Thanks, eprosenx, but if I understand right from the previous poster, what I should go with is a 240v outlet with NEMA 14-50 on either a 40 or 50-amp breaker (bear in mind - I have no idea what any of that means and am just repeating what I wrote down). Would that be enough to power the wall connector if I decide to go with that at a later date? Thanks.

 

[brkaus]

Thanks, eprosenx, but if I understand right from the previous poster, what I should go with is a 240v outlet with NEMA 14-50 on either a 40 or 50-amp breaker (bear in mind - I have no idea what any of that means and am just repeating what I wrote down). Would that be enough to power the wall connector if I decide to go with that at a later date? Thanks.

Ideally, yes. 50a breaker preferred. But let them know you may want 60A in the future, so wire is sized properly. That would give you 48a charging rate.

 

[eprosenx]

Thanks, eprosenx, but if I understand right from the previous poster, what I should go with is a 240v outlet with NEMA 14-50 on either a 40 or 50-amp breaker (bear in mind - I have no idea what any of that means and am just repeating what I wrote down). Would that be enough to power the wall connector if I decide to go with that at a later date? Thanks.

If you are running a new wire I would go with at least 6 AWG which will let you use a 50a breaker on a NEMA 14-50 receptacle. For running a brand new circuit I would never do just a 40a capable wire. You could then later switch that to a Wall Connector which can take between 15a (12a continuous) and 100a (80a continuous) (with many steps in between) and make it available to the car. If you say put in 6 AWG romex (NM cable) on a 50a breaker then with the UMC Gen 2 that comes with the car the car would charge at 32 amps. If you swapped later to a Wall Connector then it could provide 40a to the car (80% of 50a).

The Model 3 can't make use of more than 48a continuous (on a 60a breaker).

If you had the electrician put 6 awg in conduit then it is allowed on up to a 60a breaker (but while used on a 14-50 receptacle it would need a 50a breaker), so that later when you put in a Wall Connector and moved to a 60a breaker you could max the charge ability of your car at 48a. If you had future plans to have a different Tesla or more than one, then you start talking about running say a 100a circuit and being able to share it between multiple Wall Connectors (they have a communication protocol that lets them talk amongst each other to keep the aggregate load below the setpoint).

We have not talked about the capacity of your overall panel (service capacity). There are NEC calculations for how much capacity you have based on the number of square feet in your house, what kind of devices you have, etc... It is generally pretty commonly possible to put a NEMA 14-50 on a 200a panel (especially if your house has natural gas or propane for heating), but it all depends on the situation. Once you start talking about higher ampacity circuits like 100a then you really need to understand capacities a lot closer.

 

[Brenkj]

Well, the electrician said I have no space left on my circuit board, so in order to do the full 240v setup, he would have to install a new board, and then run wire to the garage - $2,659.00 all in. We have a couple of outdoor outlets that are not being used, so I might look into upgrading one of those and just resigning myself to (much) slower charging. Any other thoughts? Thanks.

 

[eprosenx]

Well, the electrician said I have no space left on my circuit board, so in order to do the full 240v setup, he would have to install a new board, and then run wire to the garage - $2,659.00 all in. We have a couple of outdoor outlets that are not being used, so I might look into upgrading one of those and just resigning myself to (much) slower charging. Any other thoughts? Thanks.

Please post pictures of your circuit breaker panel of sufficient resolution so we can see the amperage ratings on the handle ties. We also need a picture of the service schedule (list of what is what) as well as any stickers on the door to the panel (sonwe can see what breaker spots might allow installation of tandem breakers).

Just want to double check your options. Sometimes electricians miss things.

 

[Brenkj]

That’s a good point. When I asked him about space available on the panel, he just counted the slots, and said “This is a pretty big house. I’m sure they’re all being used.” Here’s a picture of the panel. The original directory is out of date (the house was renovated after it was installed but before we bought it). The notations on the panel itself are really vague, but I think they’re current. Out of the 40 slots, about half of them don’t have anything written next to them, but I’m not sure that means they’re not being used. How do you tell whether a slot is actually in use?

 

[MountainRatMat]

That’s a good point. When I asked him about space available on the panel, he just counted the slots, and said “This is a pretty big house. I’m sure they’re all being used.” Here’s a picture of the panel. The original directory is out of date (the house was renovated after it was installed but before we bought it). The notations on the panel itself are really vague, but I think they’re current. Out of the 40 slots, about half of them don’t have anything written next to them, but I’m not sure that means they’re not being used. How do you tell whether a slot is actually in use?

You need more of the panel than you have in that picture. There should be a "125" or "200" breaker in there as well as we need to see the open space (there are usually breakaway panels to add extra slots). I would also get a new electrician, did he go into loading on the house or just look at your panel and say no go?

Lots of people on here know a lot about home charging setups so keep asking away and we will try and provide answers for you.

 

[Brenkj]

The big breaker at the top says “Single Handle 200”. There is one slot that’s not occupied by an actual breaker.

 

[Brenkj]

Here’s the directory on the door. It looks like it’s original, but I know at least some of the breaker assignments are wrong now (presumably due to the remodel a few years ago).

 

[Brenkj]

Well, electrician #2 just left. He has done several Tesla installations and seemed very familiar with the requirements. He actually took the panel cover off. He said there are two slots not in use, so he thinks doing a 240V installation should be fairly routine. I don't have the quote yet, so we'll see what "routine" actually costs, but I think it's safe to say it will be less than the first quote.

 

[CruzinTX]

@Brenkj I was in the same boat as you when I first got my model 3. At first I tried the regular outlet and like what other people here have said before, it charges slow. If you commute 10 miles per day, this can always be an option where you charge daily. However, keep in mind that you will be tied to this schedule. Having said that I knew I had to go with a faster charging mechanism i.e. nema 14-50 or wall charger.

I got a quote from 3 electricians to see how much to add another outlet, nema 14-50 in this case, and the quotes ranged from $800 to $1600. The $1600 quote was adding a sub-panel with the nema 14-50 outlet dedicated to it.

Some information regarding your panel. The main circuit breaker, that has the 200 label, is the amount of amps that panel can support. You have to follow the 80-20 rule when talking about the circuit breakers. This means that if a breaker is labeled for 20 amps, you can draw 16 amps out of it. That's why if you have the nema 14-50 on a 50 amp breaker, you can draw 45 amps continuous, which will charge your car faster. Just apply the same concept to the wall charger connected to a 60 amp breaker or 100 amps. In my opinion, the nema 14-50 connected to a 50 amp breaker would suffice most of the Tesla owners here. Keep in mind you can always use other chargers as a backup plan.

Your panel is already full but you can combine some circuit breakers together and use a tandem. Just search for "tandem circuit breaker" to know more about it. This is when a professional electrician will be worth hiring/consulting so they can properly determine which breakers to combine. Keep in mind that your panel supports 240V, occupying one slot makes the breaker use 110/120V. That's why you'll see your oven or hvac occupying 2 slots since they run on 220/240V. Just a hint, if you have to combine single breakers into tandem, you need to pick alternating breakers so that they are on the same line.

Regarding the length distance of the outlet to the breaker. The closer it is to the breaker, the better. Those 6 awg wires cost a pretty penny. In addition if you can make it close to the breaker, you have less wire being exposed. Bear in mind that these wires are high amperage and best to make it short as possible.

To minimize costs, you can buy the stuff yourself and have an electrician wire it in. But if these stuff still go way over your head, best to have an electrician do it for you. IMO and to be on the safe side, just hire a professional who can make sure that the load will be to code.

Good luck and enjoy your Tesla.

 

[Brenkj]

Thanks a lot, CruzinTX (I'm also in Texas, by the way). I don't know if you've seen my last post, but the second electrician said there are two open slots in the panel and that he can do a 240V. I don't drive much, so I don't really need the super-fast-charging option, but I do need something faster than the 3-mph from a regular outlet. I'm assuming a lot of the cost is going to be labor, so is there any reason to think the super-fast option will cost much more than whatever option will get me more like 20-25 mph (which is enough for me)?

 

[CruzinTX]

Thanks a lot, CruzinTX (I'm also in Texas, by the way). I don't know if you've seen my last post, but the second electrician said there are two open slots in the panel and that he can do a 240V. I don't drive much, so I don't really need the super-fast-charging option, but I do need something faster than the 3-mph from a regular outlet. I'm assuming a lot of the cost is going to be labor, so is there any reason to think the super-fast option will cost much more than whatever option will get me more like 20-25 mph (which is enough for me)?

Personally, I don't like to be tied to just having one option to charge at home. With a fast charging option, you can even schedule it to charge in the wee hours of the morning so that a) electricity costs are cheaper and/or b) demand for electricity is lower putting less strain on the power grid. With that said, I would recommend to get the fast charging option installed.

Glad to hear you have 2 free slots open already. All that's needed to do is get a 50 amp breaker, jacketed #6 gauge 4-wire cable, outlet box, and the nema 14-50 outlet with faceplate. Installation should be a breeze if you already know where to put your outlet and the path to the breaker.

You can just think of this investment in adding this outlet a cost saving for you in terms of gas and time when you charge your Tesla. Imagine, you never have to stop to fill up gas on your way home, you can have your car charge while you sleep and it's ready to go.

 

[brkaus]

Thanks a lot, CruzinTX (I'm also in Texas, by the way). I don't know if you've seen my last post, but the second electrician said there are two open slots in the panel and that he can do a 240V. I don't drive much, so I don't really need the super-fast-charging option, but I do need something faster than the 3-mph from a regular outlet. I'm assuming a lot of the cost is going to be labor, so is there any reason to think the super-fast option will cost much more than whatever option will get me more like 20-25 mph (which is enough for me)?

Just have to ask. For short distance, your correct, the majority of the cost is labor (and overhead - drive time, etc).

It may depend on how much they think your panel can support, based on other loads in the house.

High to low -
WC / HPWC - 100A breaker - charge @ 48 amps
WC / HPWC - 60A breaker - charge @ 48 amps
14-50 plug / 50A breaker - use UMC with car - charge @ 32 amps
14-30 plug / 30A breaker - "dryer plug". - 24A w/ adaptor from Tesla
...
6-20 - 240v/20A breaker - 16A w/ adaptor from Tesla

All the outlets will be about the same cost. Sometimes there isn't adequate capacity for a 50A circuit. Your probably fine though.


I would suggest you request a 14-50 plug be wired so that it could later be replaced w/ a WC/HPWC if you so choose. That just means they need adequate wire to support 60A. The breaker would have to stay 50A until it was swapped out later.

 

[Brenkj]

Wow - Thumbtack is quite a thing! I posted my job on there and within 3 minutes I had been contacted by 4 nearby electricians. The first one gave me a quote of $400 - $450 for the 240V/NEMA 14-50 installation. And lower if I'm willing to do some of the "non-electric" manual work myself (which I will gladly do).

 

[CruzinTX]

Wow - Thumbtack is quite a thing! I posted my job on there and within 3 minutes I had been contacted by 4 nearby electricians. The first one gave me a quote of $400 - $450 for the 240V/NEMA 14-50 installation. And lower if I'm willing to do some of the "non-electric" manual work myself (which I will gladly do).

When you hire an electrician, make sure you save the invoice. Take a picture of it, add it to your calendar, make some notes and upload the file. That way if something happens with your panel, you can prove that it was done by a licensed electrician. It's just CYA, hoping you don't burn your house down. =)

 

[brkaus]

Wow - Thumbtack is quite a thing! I posted my job on there and within 3 minutes I had been contacted by 4 nearby electricians. The first one gave me a quote of $400 - $450 for the 240V/NEMA 14-50 installation. And lower if I'm willing to do some of the "non-electric" manual work myself (which I will gladly do).

If it’s right next to the panel, and there was not Sheetrock, it would be $50 in parts and 20-30 min. Add travel time, permits, profit, etc.

 

[Brenkj]

Yeah - I can crawl around underneath my house dragging a non-energized cable just as well as the next guy. All I need the electrician to do is install the breakers, drop the connection down into the crawlspace where I can grab it, and connect it to the outlet. This project is getting less expensive by the minute.