Will the Performance+ Model 3 need a higher amp circuit breaker?

[NickFie]

That's pretty much it. If you have a 200A main, then you (should) have 200A-capable wire feeding it and a 200A meter. The electrician is supposed to do a load calculation to determine your peak usage and confirm that is won't exceed the main breaker. Unless you have lots of A/C, pool pumps, double ovens, and other big power users, you're probably fine.

A load calc is not as simple as adding up all the breakers in the panel - they often total far more than the main. It's the total expected draw that matters.

Definitely have an electrician do the work.

The breakers at the top of the panel handle the feed. They should have Amp capacity marked. That's the amount you KNOW your box can handle. Probably 200 Amps. If it's lower, the electrician can work with the utility to see what would be required to upgrade to 200 Amps.

We used a Tesla-recommended electrician for the installation. He had worked in our house before, assured me the panel could handle 100 Amps for the HPWC. Still had to send a picture of the panel to Tesla to get their OK. He noted that we had converted to a natural gas dryer so the 100-Amp HPWC breakers would replace the 30-Amp dryer breakers.

 

[UltralightBeam]

I see. I think that one I linked just happened to be a 50? So I need at least 60 or higher to take advantage of the full capability of the HPWC.

How much on average for the electrician to run the wiring if everything else is good? (The panel and close proximity are all a check then in my place).. just a circuit breaker at 60-100Amp and running the connection about a foot away from the box.

 

[UltralightBeam]

Definitely have an electrician do the work.

The breakers at the top of the panel handle the feed. They should have Amp capacity marked. That's the amount you KNOW your box can handle. Probably 200 Amps. If it's lower, the electrician can work with the utility to see what would be required to upgrade to 200 Amps.

We used a Tesla-recommended electrician for the installation. He had worked in our house before, assured me the panel could handle 100 Amps for the HPWC. Still had to send a picture of the panel to Tesla to get their OK. He noted that we had converted to a natural gas dryer so the 100-Amp HPWC breakers would replace the 30-Amp dryer breakers.

We’re the ‘Tesla recommended ones’ reasonable in their quotes? Did you look around for others as well?

 

[NickFie]

We’re the ‘Tesla recommended ones’ reasonable in their quotes? Did you look around for others as well?

The Tesla-recommended electrician charged less than the estimate from the non-Tesla contractor we contacted first. His bill was LOWER than his estimate. We got a top-quality installation and smooth permit/inspection experience. Subsequently recommended the electrician to my very particular neighbor for generator installation. That went very smoothly, too.

Visible cut-off switch - flush-mounted breaker box - just visible through the door as a gray rectangle on the far wall. A long-time Tesla owner said it was the cleanest HPWC installation he had seen. We proceeded to charge his S85 at 80 Amps.

Not saying it happens all the time, that was our experience.

 

[brianman]

I’m not sure if this basically means that my home has 200A service total or something else... either way, I initially was thinking that this should be more than enough for my needs?

I think it means your panel is ready for 200A, but check the breaker at the top to see if it's a 200A breaker or not.

 

[eprosenx]

I see. I think that one I linked just happened to be a 50? So I need at least 60 or higher to take advantage of the full capability of the HPWC.

To "fully enable" the HPWC you would run 3 AWG copper in conduit and put it on a 100a breaker. This would let you charge at up to 80a if you had one of the old Model S units with dual 40a chargers. Newer S and X units top out at 72a if they have the bigger charger enabled. The Model S Long Range tops out at 48a, so you need a 60a circuit to charge a Model 3 LR at its fastest rate (this is what I installed).

Now your panel might not have enough capacity remaning to do a full 100a breaker... This depends on the load calcs. I would probably not install a HPWC with anything less than a 60a circuit even if I had to crank it down on the rotary dial to something lower due to the load calc's not allowing something higher. That way if you later convert the dryer to Gas or something you could crank up the HPWC with just a rotary dial change. If you run 6 AWG in conduit it will allow up to 60a (48a usable continuous which EVSE's are considered continuous).

 

[UltralightBeam]

So I guess to future proof this (even though we’re getting a model 3), it’s probably best to go and get the 100amp one right? Does this look right?
https://www.homedepot.com/p/Square-D-Homeline-100-Amp-2-Pole-Circuit-Breaker-HOM2100C/202824917

 

[tga]

So I guess to future proof this (even though we’re getting a model 3), it’s probably best to go and get the 100amp one right? Does this look right?
https://www.homedepot.com/p/Square-D-Homeline-100-Amp-2-Pole-Circuit-Breaker-HOM2100C/202824917

Unless you're doing the work yourself, or have already worked it out with your electrician, save your money. Many (most?) electricians don't like to use customer-supplied parts.

You still need to do a load calc to know that there's enough headroom in your service to support a 100A circuit.

Installing a HPWC on a 100A circuit is going to be way more expensive than a 60A circuit (the max the model 3 needs). Wire is more expensive, you need a disconnect switch in site of the HPWC, and labor will be higher (it's a PITA to work with that heavy wire). Unless you know you're getting another Tesla and want to share the circuit between two HPWC's, you're probably wasting your money.

 

[UltralightBeam]

Unless you're doing the work yourself, or have already worked it out with your electrician, save your money. Many (most?) electricians don't like to use customer-supplied parts.

Oh I just posted that link to see if I even know what the heck I'm talking about. And know / learn what's going into this. Definitely will be contracting an official electrician vs a hack like me!

You still need to do a load calc to know that there's enough headroom in your service to support a 100A circuit.

Installing a HPWC on a 100A circuit is going to be way more expensive than a 60A circuit (the max the model 3 needs). Wire is more expensive, you need a disconnect switch in site of the HPWC, and labor will be higher (it's a PITA to work with that heavy wire). Unless you know you're getting another Tesla and want to share the circuit between two HPWC's, you're probably wasting your money.

Would I be able to get the full 48A charge for the Model 3 on the 60A Circuit with the HPWC?

 

[tga]

Oh I just posted that link to see if I even know what the heck I'm talking about. And know / learn what's going into this. Definitely will be contracting an official electrician vs a hack like me!

Then yes, that's the right thing (assuming you have a Homeline panel, which is what you posted a link to up thread). Schneider Electric (makers of Square D) makes 2 different Square D panel/breaker lines that aren't compatible (Homeline and QO), so you have to make sure you're looking at the right one - Video: What are some of the differences between the QO and HOM load centers?

The Homeline product line is intended for residential only, while QO is residential or light commercial/industrial.

It'll probably say on the label on the door which it is. The easy way to tell is QO has the "visi-trip" indicator - it's a small clear window that shows a red flag if the breaker trips, making it easier to spot (the handle also sits in mid-position). Homeline doesn't have the visi-trip window.

Would I be able to get the full 48A charge for the Model 3 on the 60A Circuit with the HPWC?

Yes. In North America, circuits are rated as "intermittent loads." Continuous loads (more than 3 hours) need 25% more capacity, so continuous = intermittent * 1.25, or intermittent = continuous * 0.8 (that's why you see 125% and 80% tossed around). The NEC (National Electric Code) specifies that EV charging is always considered continuous, regardless of the length of your charging session. Few, if any, loads in your house are considered continuous - even heating appliances cycle on and off to maintain temperature. EV charging is probably the most intense thing your home's electrical system will ever see.

So to charge at 48A, you need a 60A circuit (48A * 125% = 60A).

 

[UltralightBeam]

Yes. In North America, circuits are rated as "intermittent loads." Continuous loads (more than 3 hours) need 25% more capacity, so continuous = intermittent * 1.25, or intermittent = continuous * 0.8 (that's why you see 125% and 80% tossed around). The NEC (National Electric Code) specifies that EV charging is always considered continuous, regardless of the length of your charging session. Few, if any, loads in your house are considered continuous - even heating appliances cycle on and off to maintain temperature. EV charging is probably the most intense thing your home's electrical system will ever see.

So to charge at 48A, you need a 60A circuit (48A * 125% = 60A).

Thank you for this detailed info! yes. it looks like this is the way I'd want to go for my circuit breaker plan as it's the min I need to get the max potential capable of the Model 3!!

 

[eprosenx]

Unless you're doing the work yourself, or have already worked it out with your electrician, save your money. Many (most?) electricians don't like to use customer-supplied parts.

You still need to do a load calc to know that there's enough headroom in your service to support a 100A circuit.

Installing a HPWC on a 100A circuit is going to be way more expensive than a 60A circuit (the max the model 3 needs). Wire is more expensive, you need a disconnect switch in site of the HPWC, and labor will be higher (it's a PITA to work with that heavy wire). Unless you know you're getting another Tesla and want to share the circuit between two HPWC's, you're probably wasting your money.

FWIW, now that I know a lot more I probably would have installed my HPWC differently. I used EMT with #6 AWG and a 60a breaker. It was only about 10' of wire. To do it over again, I would have probably pulled #4 wire (and a #8 ground) and put it on a 80a breaker. My Model 3 could not have made use of it, but visiting Model S/X or other future vehicles could have. Going all the way to a 100a breaker with #3 AWG wire would be the ultimate solution, but that would require going to 1" EMT (where I ran 3/4ths).

So even if paying an electrician, the only delta cost would be the 80a breaker vs. the 60a one, plus the higher ampacity wire. The conduit and the rest of the labor would have been the same (maybe dealing with the thicker wire might have been a bit of a pain).

In my case, I have only one 240v load (the AC). Everything else is gas, so no load calc issues.

FWIW, I see no problems with installing a higher ampacity wire and corresponding breaker but then setting the dial on the HPWC down lower if you need to fit under a load calc threshold. Obviously this is somewhat of a waste of money, but if you thought you might switch a water heater / furnace / range / dryer to gas later or otherwise upgrade your service it might make sense in some edge cases.

Also, I have not looked into this, but I know at least in commercial you can do a load study of *actual* historic load and use it to justify deviating from the standard load calculations. I have a Sense Monitor and I have a year of history that says I never remotely touch the capacity of my service.

P.S. I am not 100% sure on the disconnect switch thing. If it is *over* 60a ampacity then you need a locking disconnect in a "readily accessible" location, but I don't think many (most?) AHJ's consider that to need to be visible. Generally I think a metal clip in the breaker panel to allow it to be locked off is sufficient.

 

[mongo]

P.S. I am not 100% sure on the disconnect switch thing. If it is *over* 60a ampacity then you need a locking disconnect in a "readily accessible" location, but I don't think many (most?) AHJ's consider that to need to be visible. Generally I think a metal clip in the breaker panel to allow it to be locked off is sufficient.

The EVSE requirement:

625.23 Disconnecting Means. For electric vehicle supply equipment rated more than 60 amperes or more than 150 volts to ground, the disconnecting means shall be provided and installed in a readily accessible location. The disconnecting means shall be capable of being locked in the open position. The provision for locking or adding a lock to the disconnecting means shall be installed on or at the switch or circuit breaker used as the disconnecting means and shall remain in place with or without the lock installed. Portable means for adding a lock to the switch or circuit breaker shall not be permitted.

So it looks like a locking/ permanently attached to breaker device at the main panel is sufficient for EVSE. Thus no need for local disconnect.


EV Charging Systems

Following info is in case the circuit would be converted to other purposes in the future:

Spoiler: general disconnect info (non EVSE)

Per NEC 422.31(B), a non motor appliance of greater than 300W or 1/8 HP requires a disconnect in sight or a locking disconnect out of sight.

As of the prelininary 2014 version, the wording on lockouts was:

110.25 Lockable Disconnecting Means. Where a disconnecting means is required to be lockable open elsewhere in this Code, it shall be capable of being locked in the open position. The provisions for locking shall remain in place with or without the lock installed.

Exception: Cord-and-plug connection locking provisions shall not be required to remain in place without the lock installed.

This covers things like water heaters and such. .31 also has motor section for hardwired dishwashers.

 

[tga]

EDIT: Mongo beat me. "Nothing to see here, move along folks"

 

[mongo]

EDIT: Mongo beat me. "Nothing to see here, move along folks"

Actually, this was news to me. I had though a local disconnect was required (and unfortunately told others that ).

Also interesting that an electric water heater without visibility of the breaker panel requires a lock out also...

 

[tga]

Actually, this was news to me. I had though a local disconnect was required (and unfortunately told others that ).

Also interesting that an electric water heater without visibility of the breaker panel requires a lock out also...

Sorry, that wasn't clear. I had basically posted the same thing as you, quoting 625.23, and agreeing with the opinion that it doesn't really say anything requiring "in sight". I edited the post to remove my redundant post (I would have just deleted it if I could). The other disconnect info (water heaters) was news to me, but I suppose makes sense from a maintenance/safety standpoint.

Looking at my copy of the 2011 edition (my town is on 2011), 625.23 and 422.31(B) say the same thing as your 2014 copy. There is no 110.25 in 2011 (it goes from .24, "Available fault current," to .26, "Spaces About Electrical Equipment," skipping .25).

 

[Lasttoy]

I might have missed it?
My electrician explained this.
First, if you have 200 amp service to your house, then you can install a 100 amp breaker.
I only have 100, so he installed a 50 amp breaker.
We used 02 wire, omg, hard to bend.
Got 14.50 box at HD for $50.
Took about 2 hours. Drilling hole thru side of house was hard.
Tesla said cars looks was is supplied, and draws accordingly.
End of story
Oh, i plugged into destination charger at Hilton in Daytona last week and smoked it. It was wired wrong.
My car has 2 inverters. I can suck more amps. The pole wiring would not handle my car. It letterly smoke before i unplugged.
Management knows, they are having it fixed.

 

[mongo]

First, if you have 200 amp service to your house, then you can install a 100 amp breaker.
I only have 100, so he installed a 50 amp breaker.

Not the right way to do it (panel could be at max to begin with)

We used 02 wire, omg, hard to bend.

Why? That doesn't match with 50A breaker.

Tesla said cars looks was is supplied, and draws accordingly.

EVSE pilot signal tells car the max it can draw.

Oh, i plugged into destination charger at Hilton in Daytona last week and smoked it. It was wired wrong.
My car has 2 inverters. I can suck more amps. The pole wiring would not handle my car. It letterly smoke before i unplugged.

It was wired badly (loose connection), failed, or was set to the wrong current limit (with the wrong sized breaker). Car only draws up to the amount the EVSE equipment it says it can...

 

[Antares Nebula]

Unless you're doing the work yourself, or have already worked it out with your electrician, save your money. Many (most?) electricians don't like to use customer-supplied parts.

You still need to do a load calc to know that there's enough headroom in your service to support a 100A circuit.

Installing a HPWC on a 100A circuit is going to be way more expensive than a 60A circuit (the max the model 3 needs). Wire is more expensive, you need a disconnect switch in site of the HPWC, and labor will be higher (it's a PITA to work with that heavy wire). Unless you know you're getting another Tesla and want to share the circuit between two HPWC's, you're probably wasting your money.

Besides the added expense, is there any other drawback. For example, does the 100A circuit risk overloading the single wall charger?

(Or does it not matter? In the sense, that even in the future if you had two wall chargers, you may not be using them at the same time, so it is the same risk of having a 100A circuit for a single wall charger being used at times. ??)

 

[mongo]

Besides the added expense, is there any other drawback. For example, does the 100A circuit risk overloading the single wall charger?

(Or does it not matter? In the sense, that even in the future if you had two wall chargers, you may not be using them at the same time, so it is the same risk of having a 100A circuit for a single wall charger being used at times. ??)

Available power does not overload anything. The condition that a 100Amp circuit would impact is if there were a resistive failure in the wall connector or vehicle charger, in which case you could have a higher fault current.