Any benefit of Tesla home charger vs 220 outlet?

[Ali’sMax]

Ali’sMax: Another thing I meant to mention: for anything over 60A (which you have now and will have with the new breaker installed) there must be a disconnect which can be locked open. I assume you have that but thought I'd better mention it in case it got overlooked. The guy that pulled my wire knew about this because he'd installed several HPWC's on his previous job but his boss didn't.

Thank you so much for detailed explanation.
My electrician said he’ll bring a pair of 100amp breaker and No 3 wire to do the swap.
I have solar and time of use bill so we charge cars at night, > 99.9% time nothing is on except charging cars, my panel intake 225amp so not really worry about blowing up breaker panel
What is a disconnect? Is it the main breaker switch?
Another question, if max amp output is 72amp why list 100amp breaker with 80amp output if the car can’t charge above 72amp?
I got my X100D near Xmas 2017, from previous posts they said now cars max at 48amp is that why my husband’s 2018 75S won’t get the same mph charge by the wall charger?

 

[MorrisonHiker]

Another question, if max amp output is 72amp why list 100amp breaker with 80amp output if the car can’t charge above 72amp?
I got my X100D near Xmas 2017, from previous posts they said now cars max at 48amp is that why my husband’s 2018 75S won’t get the same mph charge by the wall charger?

If you connect the two wall connectors for load sharing, combined they could use 80 amps. If both are charging, it would be split 40 amps/40 amps. Once one car stops charging, the other car would ramp back up to 48 amps or 72 amps, depending on the charger it has installed.

Also, if you had a pre-refresh Model S with dual chargers, it would be able to charge at 80 amps.

 

[Rocky_H]

What is a disconnect? Is it the main breaker switch?

You may have seen on TV shows those boxes with a big handle on the right side that you can grab and flip up or down to connect or disconnect power. That's what people are usually talking about as "a disconnect". But it does generally fulfill the electrical code requirement to use the breaker if you get a locking clip for it. Those are a metal bracket kind of thing that can snap onto your circuit breaker, so you can keep it locked off if needed. That can generally serve as a disconnect, because the code says "lockable", so the cliip thing can cover that.

Another question, if max amp output is 72amp why list 100amp breaker with 80amp output if the car can’t charge above 72amp?

That's generally because of what you can easily get. A 90A breaker can cover a 72A continuous feed, but most electricians don't keep 90A breakers with them, and a lot of local stores might not keep them in stock. They generally have the common even numbered sizes in the large breakers, like 60, 80, 100. So if you can't find a 90, you could just do a 100A circuit to still supply the 72A.

I got my X100D near Xmas 2017, from previous posts they said now cars max at 48amp is that why my husband’s 2018 75S won’t get the same mph charge by the wall charger?

That doesn't really have to do with the recent change now. For the past couple of years, they had different chargers included based on the two battery sizes. The 100's got the 72A onboard charger, and the 75's got the 48A onboard charger.

 

[StealthP3D]

Ali’sMax: Another thing I meant to mention: for anything over 60A (which you have now and will have with the new breaker installed) there must be a disconnect which can be locked open. I assume you have that but thought I'd better mention it in case it got overlooked. The guy that pulled my wire knew about this because he'd installed several HPWC's on his previous job but his boss didn't.

To clarify that, a disconnect is not required except for an outlet. If you hardwire a HPWC, even with a 100A breaker, a disconnect is not required. In my opinion, that's the way to go. Don't wimp out now, you only want to run the power once. If you get another Tesla you might want to charge them both at the same time or have quick charge capability.

 

[davewill]

To clarify that, a disconnect is not required except for an outlet. If you hardwire a HPWC, even with a 100A breaker, a disconnect is not required. In my opinion, that's the way to go. Don't wimp out now, you only want to run the power once. If you get another Tesla you might want to charge them both at the same time or have quick charge capability.

I don't believe this to be correct. You would need the disconnect even if hardwired. In fact, the disconnect is generally only required if the circuit is greater than 60a, and almost nobody uses an outlet for residential circuits that big.

 

[ajdelange]

intake 225amp so not really worry about blowing up breaker panel

We're not worried about that so much as we are about getting you past inspection. Insurance companies aren't in business to pay out claims. They are in business to collect premiums. Were you to have a fire from whatever cause and they found electrical work they will try to deny the claim.

What is a disconnect? Is it the main breaker switch?

A disconnect is, as the name suggests, a means of disconnecting the charging equipment from the supply. A breaker is a disconnect and the main breaker in your panel is the service disconnect (usually). But for charging an electric vehicle a second disconnect is required to be located near the charging equipment and must be able to be locked open. The gray box below the HPWC in the photo is a suitable disconnect switch.

Another question, if max amp output is 72amp why list 100amp breaker with 80amp output if the car can’t charge above 72amp?

Again, it is a question of code compliance. The HPWC can handle a maximum load of 80A. Your car may only be able to handle 72 amps but you can connect a second HPWC to the circuit. These two will share loads between the connected vehicles such that the total is 80 Amps. Because it is possible that charging may take more than 2 hours these loads are considered "continuous loads" and breakers must be sized at 125% of the load. Hence for 80A you need a 100 A breaker.

I got my X100D near Xmas 2017, from previous posts they said now cars max at 48amp is that why my husband’s 2018 75S won’t get the same mph charge by the wall charger?

I can't speak to the S but X's made after some time in December 2018 are limited to 48 A. Prior to that an X could draw 72 A. If you currently have an 80 amp breaker the most the HPWC can supply is 64 A if the car can take that much. The S may have the same limitation (48 A) as the X. I'm sure someone here will have the answer on that. But also keep in mind that the S is a lighter vehicle than the X so that a watt hour of charge will carry it further. Thus charging an S at 48A should yield higher mph than charging an S at 48A.[/QUOTE]

 

[ajdelange]

To clarify that, a disconnect is not required except for an outlet. If you hardwire a HPWC, even with a 100A breaker, a disconnect is not required.

Article 625.43 Disconnecting Means. For 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 lockable open in accordance with 110.25.

The HPWC is rated at 80 A so that technically the disconnect would be required even if wired to a 50 Amp breaker but the amount of current it will provide is set by the little rotary switch. I don't believe any inspector would ding you for not having the disconnect if configured for 50A but you never know.

 

[StealthP3D]

I don't believe this to be correct. You would need the disconnect even if hardwired. In fact, the disconnect is generally only required if the circuit is greater than 60a, and almost nobody uses an outlet for residential circuits that big.

Maybe that's correct. I know the inspector who just inspected the install my electrician did in July seemed to be a real stickler but he didn't seem to notice there was no disconnect. It's on a 100 amp circuit.

 

[MorrisonHiker]

Maybe that's correct. I know the inspector who just inspected the install my electrician did in July seemed to be a real stickler but he didn't seem to notice there was no disconnect. It's on a 100 amp circuit.

The disconnect doesn't always have to be as shown in the pictures above. In my install, Tesla added a separate subpanel with breakers for each wall connector.

 

[ajdelange]

Maybe that's correct. I know the inspector who just inspected the install my electrician did in July seemed to be a real stickler but he didn't seem to notice there was no disconnect. It's on a 100 amp circuit.

He is plainly unaware of Article 625. In any event you have an installation which does not meet code and the question becomes how your insurance company would treat this should there be a claim. I have absolutely no knowledge of what might happen nor any thoughts as to what I think you should do.

 

[Rocky_H]

He is plainly unaware of Article 625. In any event you have an installation which does not meet code and the question becomes how your insurance company would treat this should there be a claim. I have absolutely no knowledge of what might happen nor any thoughts as to what I think you should do.

The homeowner's obligation as far as insurance CYA is to get an inspection. That's it. The insurance company can't do squat about that if it was approved by the inspector. People make fun of having to pay for permits and inspections because of feeling like they don't do a good job or they are a waste of money, but that's what you're paying for--transfer of liability. It's not on the homeowner if the inspector approved it.

 

[ajdelange]

The disconnect doesn't always have to be as shown in the pictures above. In my install, Tesla added a separate subpanel with breakers for each wall connector.

That's so. It can be in any form as long as it is readily accessible and can be locked open per Article 110.25. Kind of curious as to how they implemented the lock open feature on a breaker.

 

[ajdelange]

The homeowner's obligation as far as insurance CYA is to get an inspection. That's it. The insurance company can't do squat about that if it was approved by the inspector.

They can refuse to pay. You can then sue. Will you prevail?

 

[Rocky_H]

They can refuse to pay.

Sure they can. Any insurance company can deny anything for any reason or no reason and some of them do. Let me tell you a story. My wife worked at a law office when we were in college. It was one of those personal injury, ambulance chaser places. We got to chat with one of the lawyers there when they were having a going away party for her. He was kind of worked up as he was talking with us about different insurance places, and one in particular who was horrible: Allstate. When he was at his university getting his law degree, one of the entire classes he took was entitled "How to get money out of Allstate". I'm not joking. They were absolutely notorious in the legal profession for being gigantic A-holes, because they had decided that it was most profitable to just fight their customers and always deny 100% of their claims. So that's what they did; it was their standard procedure. Customers would have to fight them and sue their own insurance company to force them to comply with the law and their own coverage contracts to make them pay out on claims. But a lot of people were discouraged by being denied and felt that going through a whole law suit would be too much expense and hassle and not worth it, and so they would feel hurt but just come up with the money out of pocket. That was obviously pure profit for Allstate for however many people they could emotionally beat down like that to avoid paying out.

The guy had a great line about how pissed off he got whenever he saw those nice looking Allstate commercials, where they pretend to be so helpful:
"The Good Hands people?!?! NO!!! It's not like THIS:"
[cupped hands held together, like in the commercials]
"It's like THIS!"
[double flipping the bird]

You can then sue. Will you prevail?

Yes--definitely. It's very rare, though, for most insurance companies other than Allstate to just deny claims in violation of the law and their policies and make their own customers sue them. That's a quick way to destroy your ratings and customer reputation, so most companies won't do that.

 

[davewill]

They can refuse to pay. You can then sue. Will you prevail?

Honestly, yes. It's very settled law. In fact, generally they can't refuse to pay even if it wasn't inspected.

 

[ajdelange]

I wrote what I did because of two events. In one I was in a bar in San Francisco waiting for some people. A guy came along and asked if he could sit down in the booth as the place was crowded. I said he was certainly welcome until our friends came. We started talking and in the course of the chat in response to the usual "what do you do?" he responded that he worked for a law firm that sued insurance companies when they refused to pay claims. I never forgot that.

The second experience was while trying to get insurance for our summer place. Many policies have an "occupany risk" clause. If the house is unoccupied for more than 30 days and it burns down they won't pay anything. At least in this case you are warned in the contract. I just don't trust insurance companies. I have never had any life insurance other than the minimal amount that came as a job perk.

Two of you seem to be certain that I would prevail in court and I assume you have some legal knowledge to back that up. I just heard a line from a TV program my wife was watching as I passed by "Anyone who tells you a court case is predictable has never been involved in more than one".

Another thing that should be considered in this case is that every article in the NEC is in there for a reason. When something nasty happens with electricity industry participants are asked to forward reports to NFPA which considers them and if it seems likely they will ever happen again an article is added to the code to try to prevent repeat occurrences. Again this is insurance companies trying to maximize profit and so the code is pretty conservative. So why does the code call for a disconnect? 60*240 = 14.4 kW is a lot of juice. When I am charging my car at 72 A (17 kW) the temperature of the charging cable rises 30 ° above ambient. I'm guessing that requirement is in there for cases where, for example, someone trips over he charging cord pulling it part way out setting off an arc. With the conveniently located disconnect one can interrupt the current without having to run to the breaker panel in another room which may be some distance. There has been one report here of a case where a lug in the HPWC was not properly torqued. Fortunately this did not lead to a dramatic failure but I imagine it is that sort of thing against which Article 625.43 is trying to protect.

 

[StealthP3D]

So why does the code call for a disconnect? 60*240 = 14.4 kW is a lot of juice. When I am charging my car at 72 A (17 kW) the temperature of the charging cable rises 30 ° above ambient. I'm guessing that requirement is in there for cases where, for example, someone trips over he charging cord pulling it part way out setting off an arc.

I'm pretty sure the reason Tesla EVSE and the Tesla battery management system are both sensitive to the quality of electricity supplied is so they can disconnect electrical connections in a few milliseconds if something is not right (as would be the case if the charge plug was forcibly ripped from the charge port). This could stop an arcing charge port about a million times quicker than any manual disconnect, regardless of how conveniently it was placed.

With the conveniently located disconnect one can interrupt the current without having to run to the breaker panel in another room which may be some distance. There has been one report here of a case where a lug in the HPWC was not properly torqued. Fortunately this did not lead to a dramatic failure but I imagine it is that sort of thing against which Article 625.43 is trying to protect.

Or assisting an industry preference to sell more electrical equipment.

 

[ajdelange]

I'm pretty sure the reason Tesla EVSE and the Tesla battery management system are both sensitive to the quality of electricity supplied is so they can disconnect electrical connections in a few milliseconds if something is not right (as would be the case if the charge plug was forcibly ripped from the charge port). This could stop an arcing charge port about a million times quicker than any manual disconnect, regardless of how conveniently it was placed.

Yep, they are designed to do that. And those protective features always work as they are supposed to just as the touchscreen, autopilot, batteries, cruise control, inverters, contactors, motors, windshield wipers, sound system, heat pump, doors and windows, charging port ... always work as they are supposed to. And since all BEV's for which charging equipment are installed in the US are TesIas I guess we really don't need those disconnects after all.

Or assisting an industry preference to sell more electrical equipment.

The goal of the National Fire Protection Association is to prevent fires. If you want to be cynical about, and I think you are at least somewhat justified in being so, the reason they want to prevent fires is because they are largely composed of insurers who don't want to be paying out claims.

The system isn't perfect and inspectors, as in this example,often don't know what they are talking about. I had one make me disconnect a grounding rod at the far end of my house, even though it meant I had a better grounding system, because fault current from a lightening strike at that end would pass through the grounding conductor inside the house to get to the other grounding rod. Of course I disconnected it while he was there. What he didn't catch was that the conductor between the two grounding rods was in buried conduit totally outside the house.

 

[MorrisonHiker]

That's so. It can be in any form as long as it is readily accessible and can be locked open per Article 110.25. Kind of curious as to how they implemented the lock open feature on a breaker.

The subpanel they installed doesn't have a door so the breakers are always visible. It passed inspection so I guess it met the requirements.

 

[ajdelange]

It met the inspectors requirements even though it technically doesn't meet the code. You can buy auxilary devices to attach to circuit breakers to lock them open if you want to but I don't see the need. The reasons for the lockout requirement are obvious in an industrial setting but I can't see myself padlocking my disconnect open if I need to work on the HPWC in my residential garage. The switch will be a convenient way to deenergize for any such work but I am not fearful that my wife will come along and start fiddling in the innards thinking that it is deenergized when it's live.