70amp main breaker - what can I install?

[mashimaro1628]

Hi

I've been reading to a lot of various topics in this forum about Teslas and I finally ordered a LR MY myself last month, it won't come for a long awhile but it's ok I can wait. I finally decided to create an account so I can ask questions here and hopefully can get some insights.

I've been contacting various licensed and one non-licensed electricians recently. I live in a condo and only have a 70 amp main breaker (pic attached, I'm unit#A). The one non-licensed electrician came and said I can install a NEMA 14-50 with no problem and gave me a quote (which is cheapest out of all the ones that came). Then the other licensed electricians came in various times in the next few days and each came to my place and look at the panels, three of them saids the max I can do is 14-30 without tripping the circuit (14-50 is not possible they said) and the last one came yesterday and said he wouldn't even risk doing a 30amp if I hired him and tell me to just stick with a 5-15, it would most likely trip the circuit or maybe worse.

Am I really out of luck? Anyone else have a similar situation like me? 5 electricians came, and they all gave a different answer. I'm so frustrated and this has cause so much anxiety. My dream would be to install a 14-50, but I would be ok to go with a 14-30, just not the 5-15. I just want to get the fastest without burning down my house.

 

[ucmndd]

The reason you got 5 different answers is that there is no cut and dry yes/no answer to be had based on looking at your panel. You have to do a load calculation.

In other words - you have a 70 amp electricity budget. The only way to figure out how much is left over for the car is to determine what you’re already spending, particularly at the times you’ll be charging your car.

The obvious concern is your HVAC, which is that 40 amp breaker. Looks like everything else is basically lights and plugs. The main question to answer is how many amps can you provide your car, while also ensuring enough overhead for your regular household needs and allowing your AC unit to start and run as needed without tripping your main breaker?

IMO a 14-30 would be a pretty safe bet. That will get you 24 amps to the car (about 5kw assuming your building is fed by 3 phase power and you have 120/208v service), leaving ~46 amps for all the rest of your house loads. If you’re charging overnight when you’re not running the microwave, washing machine, etc. that should be plenty.

A 14-50 will only get you another 8 amps using the included mobile connector. In theory this would be fine too although I can see why an electrician wouldn’t want to install a plug like that that could potentially draw a full 50 amps. A 14-50 with a 40 amp breaker, which is generally allowed by code, may be a safer option.

None of this is a “burn the house down” sort of risk. That’s what breakers are for. Worst case you end up with nuisance trips.

 

[LoudMusic]

70A is not much to work with. Modern houses are built with 200A or more. Depending on what all you have in the house consuming electricity throughout the day, you might be limited on what you can do for the car. The 40A breaker is probably your airconditioner? Judging by the remaining 20A breakers I'd guess your stove, water heater, and dryer are gas?

Also, a local electrician can probably glance at a panel and tell you how likely it is to support additional load without causing problems.

You could install a power monitor on the main input and see what the maximum is that you draw over the course of a few weeks (or months, based on Tesla deliver times currently ...), and add a breaker based on those results.

I understand the desire to be able to charge the car more quickly. But maybe think more about how much driving you currently do, and how much charging is necessary. Even a 15A outlet can put more than 30 miles back in the car overnight. Do you have existing outlets where you'll be parking the car?

 

[jcanoe]

You want to do this right, the first time.

I always start by recommending that you figure out how many miles you drive per weekday and on the weekend. (Most drivers in the US drive approximately 30 miles per day (over 12 months that is ~11,000 miles per year.)

Here are the home charging circuit options commonly used with the current Tesla Model Y vehicle.

Circuit amperage / Max charging amperage (always 80%) / Power in kW / Maximum range added per hour of charging
15A / 12A / 2.8kW (at 240V, 1.4kW at 120V) / Up to 7 miles per hour (at 240V) added when charging, else 3 to 4 miles per hour at 120V
20A / 16A / 3.8kW (at 240V, 1.7kW at 120V) / Up to 14 miles added per hour (at 240V), else up to 7 miles per hour added at 120V
30A / 24A / 5.7kW (common dryer circuit) / Up to 21 miles added per hour
40A / 32A / 7.7kW / (the maximum charging amperage supported by the Tesla Gen2 Mobile Connector) / Up to 29 miles added
50A / 40A / 9.6kW / (the maximum charging amperage when using the NEMA 14-50 receptacle, plug) / Up to 36 miles added
60A / 48A / 11.5kW / (the maximum charging amperage when using the Tesla Gen3 Wall Connector (hard wired only.) / 42 miles added

The Tesla Gen2 Mobile connector comes with the common home NEMA 5-15 receptacle power plug adapter, you can purchase additional plug adapters including 6-20 (20A/240V), 14-30 (30A/240V), 14-50 (50A/240V). When used with the NEMA 14-50 plug adapter the Tesla Gen2 Mobile Connector is limited to 32A and could also function at 32A on a 40A circuit with the NEMA 14-50 receptacle and plug adapter (40A is allowed with a NEMA 14-50 receptacle if there is insufficient capacity in the panel for adding a 50A circuit.)

The Tesla Gen3 Wall Connector is designed to be hard wired into the circuit (no plug). The Tesla Gen3 Wall Connector can be configured for 120V or 240V for any circuit rated from 15A up to 60A. The Wall Connector can be installed indoors or outdoors and is fully weather rated. The charging cord on the Tesla Gen3 Wall Connector is 24 feet in length (the Tesla Gen2 Mobile Connector charging cord is ~18 feet in length, ~20 feet including the power plug adapter and the Mobile Connector chassis.) (Don't dismiss getting the Tesla Gen3 Wall Connector just because you may be limited to a 30A or lower amperage circuit. The Wall Connector can be readily configured, hardwired into these circuits too. While not enabling charging any faster than the Tesla Mobile Connector when used with 40A or lower amperage circuits the longer charging cord and the all weather design makes the Wall Connector a good choice.

Don't overlook adding a 240V/20A circuit. This circuit can be used with the NEMA 6-20 receptacle and the Tesla Gen2 Mobile Connector with the NEMA 6-20 power plug adapter, also with the Tesla Gen3 Wall Connector configured for a 240V, 20A circuit. This circuit is capable of adding up to 14 miles of range to the Tesla vehicle per hour (approximately 5% of the battery charge added per hour.) If you have at least 6 hours available to charge, i.e. midnight to 6:00 A.M. you can add almost 100 miles of driving range to the Tesla Model Y.) In many cases this is all you would need for daily charging at home.

In situations where available capacity to add new circuits is limited an electrician can easily repurpose an existing 120V/15A or 120V/20A circuit for 240V. The limitation is that to be capable of being changed from 120V to 240V using the existing wiring the circuit can have only one receptacle (outlet). When you change from 120V to 240V, for the same amperage, you double the power and the number of miles of range that can be added to the EV per hour of charging.

 

[WindPower]

You could install a power monitor on the main input and see what the maximum is that you draw

I renovated a 100 year old house which only had 60amp 220v service. I installed a power meter on the air conditioner circuit (20 amp) and ran it for a week to see what the real max current draw was. The rest of the usage was low except for the pool pump (on a timer) and dishwasher. My stove and clothes dryer were gas. My electrical contractor ran a power usage calculation and determined I could spare 30 amps during off peak (midnight to 6am). He installed a 30amp circuit and I dialed the EVSE to 24 amps and set the EVSE timer to run off peak.
It can be done but it takes some number crunching.
I was perfectly happy with the charging rates since I’m driving at most 250 miles per week. Most weeks I’m less than 200 miles so twice a week charging was fine. I sold that house and in the new house have 100amp service. My new EVSE is running at 40amps and now charge once a week.

 

[ChrisMPK]

I would wire and install a 30 amp receptacle like two of your electricians said. If you have issues with tripping, you can manually dial the charge rate down in the car. 50A on that panel is just ridiculous.

 

[roblab]

This is why you can adjust your charging rate at the car. Just dial it down to around 80% of the breaker, and if you charge after midnight you'll never have a problem. Charging at night also gives you a large block of time so that charging slow can still fill your car.

 

[jcanoe]

The Tesla Mobile Connector and Tesla Wall Connector are programmed to follow the electrical code requirement, only enable charging at up to 80% of the circuit rating. If you are tripping the breaker at 80% then something is wrong.

 

[mashimaro1628]

Just got off work, thanks for all the replies so far, that's why I loved this forum .

Looks like everything else is basically lights and plugs.

Yes, just lights, I don't have anything crazy besides the HVAC like you said, and both washer and dryers are gas.

A 14-50 with a 40 amp breaker, which is generally allowed by code, may be a safer option.

but none of the electricians are willing to do that, they just said it's impossible, so I'm good with 30 amp if that's the only choice, it's more than enough for my use. Heck, even 5-15 is good for my use but if I have a choice without tripping the circuit, I want to get the fastest speed if possible.

 

[mashimaro1628]

I would wire and install a 30 amp receptacle like two of your electricians said. If you have issues with tripping, you can manually dial the charge rate down in the car. 50A on that panel is just ridiculous.

Looks like you are in Monterey Park? Are you in a house or condo? Which electrician did you used to install your's?

 

[jabloomf1230]

I would go with 14-50 and if the main breaker keeps triping, limit the charge current with the Tesla app. You can probably fine tune things by scheduling charging during night time.

 

[mashimaro1628]

70A is not much to work with. Modern houses are built with 200A or more.

lol, I understand your point, who doesn't want a new house? I'm not trying to bash you, but it is what it is though, I'm not going to shop for a new house because of a Tesla, I'm pretty sure some Tesla owners out there would be able to do non 5-15 home charging without a 200A.

The 40A breaker is probably your airconditioner? Judging by the remaining 20A breakers I'd guess your stove, water heater, and dryer are gas?

Yes to both questions.

Also, a local electrician can probably glance at a panel and tell you how likely it is to support additional load without causing problems.

I already said in my first post I had 5 came, but all gave me different answers. The consensus is 14-30 only, 14-50 impossible

Even a 15A outlet can put more than 30 miles back in the car overnight.

Yea, I understand that, but I rather have a speedy charge than a slow charge. You can say I'm stubborn but I like things as fast as possible without damaging other things, I'm using a Samsung phone and I always charge using fast charging rather than regular slow charging if possible, for example.

Do you have existing outlets where you'll be parking the car?

Yep, I have my own garage, I'm glad too. It would've been a nightmare with high installation fees if I don't have my garage.

 

[mashimaro1628]

The Tesla Gen3 Wall Connector is designed to be hard wired into the circuit (no plug). The Tesla Gen3 Wall Connector can be configured for 120V or 240V for any circuit rated from 15A up to 60A. The Wall Connector can be installed indoors or outdoors and is fully weather rated. The charging cord on the Tesla Gen3 Wall Connector is 24 feet in length (the Tesla Gen2 Mobile Connector charging cord is ~18 feet in length, ~20 feet including the power plug adapter and the Mobile Connector chassis.) (Don't dismiss getting the Tesla Gen3 Wall Connector just because you may be limited to a 30A or lower amperage circuit. The Wall Connector can be readily configured, hardwired into these circuits too. While not enabling charging any faster than the Tesla Mobile Connector when used with 40A or lower amperage circuits the longer charging cord and the all weather design makes the Wall Connector a good choice.

Yea, but that alone cost an extra $500 .

 

[mashimaro1628]

I would go with 14-50 and if the main breaker keeps triping, limit the charge current with the Tesla app. You can probably fine tune things by scheduling charging during night time.

the problem is, none of the electricians that came would be willing to risk their license to do a 14-50 with my panel, they all said "it's impossible" .

 

[jcanoe]

Yea, but that alone cost an extra $500 .

The cost difference between installing a receptacle (could be 14-30 receptacle (30A) or other circuit rating and receptacle) is not the full price of the Wall Connector ($495). There are a number of things you won't need to purchase, the delta can be less than $200 after all costs.

 

[mashimaro1628]

The cost difference between installing a receptacle (could be 14-30 receptacle (30A) or other circuit rating and receptacle) is not the full price of the Wall Connector ($495). There are a number of things you won't need to purchase, the delta can be less than $200 after all costs.

I'll ask around, but everything is so pricey in CA, I don't think they are willing to do it for $200 or so

 

[mashimaro1628]

The cost difference between installing a receptacle (could be 14-30 receptacle (30A) or other circuit rating and receptacle) is not the full price of the Wall Connector ($495). There are a number of things you won't need to purchase, the delta can be less than $200 after all costs.

Also, I'm not super familiar with the wall charger. For my case, the electrician would still need to install the 30amp breaker on the subpanel or something?

 

[jcanoe]

I'll ask around, but everything is so pricey in CA, I don't think they are willing to do it for $200 or so

To clarify, when you install a new electrical circuit and receptacle for your home to charge an EV there are some additional costs that you would not have when installing the Wall Connector.

New circuits that terminate at a receptacle must have ground fault circuit interrupt (GFCI) protection. For higher amperage circuits this is accomplished with a GFCI circuit breaker that costs ~$100 (a standard circuit breaker costs under $20)

If installing a 14-50 receptacle a good quality one can cost almost $100 (never use a $10 14-50 receptacle from one of the big chain stores for charging an EV.)

You would want a cable organizer, these costs about $20 to $35. When you install the Wall Connector you don't need a separate cable organizer for hanging up the cable or mounting the Mobile Connector

The Tesla NEMA 14-50 power plug adapter costs $45 (the NEMA 14-30 power plug adapter now also costs $45) from the Tesla store.

The wiring is somewhat less expensive when installing the Wall Connector (2 wires instead of 3 wires).

When you add up the cost of all of the components you would not need when installing the Wall Connector the net difference in cost is around $200 (meaning the Tesla Wall Connector only ends up costing you $200 more than if you use the Tesla Mobile Connector.) The savings can be even more if you were planning to purchase a second Mobile Connector to keep in the Tesla Vehicle (avoids buying a second Mobile Connector, cost $275)

 

[jcanoe]

Also, I'm not super familiar with the wall charger. For my case, the electrician would still need to install the 30amp breaker on the subpanel or something?

The Wall Connector performs the same function as the Mobile Connector, enables you to charge your Tesla vehicle. The Wall Connector has a longer charging cord (24 ft versus 18 ft for the Mobile Connector). The Wall Connector does not come with a plug, is hard wired into the circuit. The Wall Connector can be configured for use on any circuit including: 15A/20A/30A/40A/50A/60A. The electrician could install the Wall Connector for use on a 30A circuit.

 

[Tronguy]

Hokay. I'm not a power engineer, unless one counts 48V. But I work in telecom. And, there's this thing: How many circuits do you need for, say, 1000 users?
Not everybody is going to pick up their phone at the same time. When something like that does happen, that's when one might have to wait quite a while before there's some dial tone.
Similarly: If one goes to one's electrical panel and counts up the amperages of all the breakers one has in there, there will be more amperage than the main breaker, nearly always. Then, why isn't the main popping open all the time? Because nobody has All The Circuits Turned On At the Same Time, Running Max Amps When They Do.
At least, for a house/condo/what-have-you is properly designed.
Contrary to Popular Opinion around these parts, this is not some throw-a-dart-at-the-wall-and-guess-mightily. The National Electric Code has Things to Say about the sizing of panels and how much of a load to put on one, or even how much additional load can be put in there.
Now I'm going to say something that's not going to ring popular around here. I really, truly, don't want people popping breakers as a regular thing, not even if people say, "Well, that's what breakers are for!"
No. Breakers aren't there so one can overload one's panel safely. Breakers are there to save your life, in extremeis. The reason: Breakers are not 100% reliable. Just like anything else.
Take, say, a 15A breaker. It's designed to go off at 15A, plus or minus 10% or so. But - this thing is a heating element. Like a light bulb. And, like a light bulb, the heating element expands and contracts when it gets hot. That means the metal in there is getting flexed. I'm a-telling you: These things are not designed to run at or near their limit: If you do, then you run the risk that it will fail open. That's not so bad - you go and get a new one. But you also run the risk that it will weld itself closed. First, if it does that, it can catch on fire and burn your breaker panel down. That's if you're lucky. Or, you might run more current through some set of wires than they're designed to handle. This doesn't precisely mean that the copper is going to melt. What this does mean is that the copper is going to get warm. And then hot. And then hot enough to catch the wood and/or insulation inside the walls on fire. Whee! Again, I'm deathly serious about this.
What breakers are really well designed for is to catch shorts. Short circuit an extension cable, run 3X the normal amount of current through a breaker, and that breaker will go POP! with alacrity, saving the world. That's what they're designed to do - catch short circuit over currents. Not people running 20A through a 20A breaker for hours at a time.
And we're not talking just the individual circuits, either: We're talking the gauge of wire going into the Main breaker at the top as well. You want 200A service? You're going to need 200A-sized wire, too.
Various serious safety experts have trodden all over the National Electric Code. As a civil engineer I once lived with explained to me, in these kinds of code books, on each page, is at least one house that burned or fell down and that page has a rule that was made so it wouldn't happen again.
Say it comes time for you to sell your house. In some jurisdictions, you have to have a certificate of occupancy, issued by ye local building inspector. Think they'll miss something like this? Building inspectors of the structural, plumbing, and electrical type check new construction to make sure it follows the various codes. And that's because Society at Large has decided that houses getting destroyed (along with the possibility of the occupants getting destroyed) is a Bad Thing, and have therefore passed laws.
Real, licensed electricians know all about this. They also have insurance that states that they'll follow the NEC, which they do with good will. They like repeat, alive customers, not non-repeating dead ones. Or the lawsuits the latter would entail, especially with the possibility of jail time.
So, first, I'm not at all surprised that the Licensed Electricians went hmm... haa.. and told you cost numbers you didn't want to hear. And I'm further Not Surprised that a non-licensed electrician said, "Sure, Joe, have it done in a jiffy. Make sure you pay up in cash." You'll be lucky to get his right address and name. And it would be interesting, and probably futile, to track down any previous customers of this gonzo to see if anybody had trouble.
If a licensed electrician says Not To Do Something, Then Don't Do It.
You got kids? Got a spouse? You might be willing to take risks, but what if you get out of a burning building alive with your kid, but Mommy's dead? Or vice versa. Or you don't get out alive, but others in your family do, with a burned-out house behind them. Think they'll think of you with rosy thoughts?
I had the unfortunate experience of watching the house across the street burn very nearly to the ground shortly after Christmas one year. Most likely cause was a freezer, kept in the garage, developing a fire. And said freezer was right on top of the gas meter, also in the garage. The three people (and dog) in the house at the time were lucky to get out alive. Yeah, it would have been nice if the breaker had popped early on.. but it was an old house.