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Wall Charger what amp for breaker
- Thread starter bgrynn1873
- Start date
everydaychris
Active Member
You mean 60C, not 60A breaker/circuit, right? Just to confirm I didn't confuse anyone. If the right wire is used according to the code, 60A is fine. For 60C, right, if you use gauge 6 wire. I guess if you go to lower gauge, 60C might be okay.
Pluturi
Member
I was just going to ignore the comments made above about what the Tesla manual says, but I can't leave it as someone has already taken the wrong conclusion from this discussion.
As pointed out by Rocky, you can't use 6/2 NM cable (Romex) for the Wall Connector application and use it at its maximum capability of 60A, but there are other types of 6/2 cable (e.g., THHN in conduit or MC) that CAN be used perfectly safely in this application. Romex is the cable that is limited to 60C; the other types go to 75C or 90C. This is completely consistent with the Tesla manual which says you should use conductors rated for 90C. In other words, Tesla is saying DON'T USE 6 AWG ROMEX, which is also what Rocky said. Neither is saying you can't make a 60A circuit with the Tesla Wall Connector.
All of this is based on the capability of the wire/sheathing and how it is pulled through the house. It is defined by the wire's ampacity and is clearly spelled out in this chart:
Ampacity Charts - Cerrowire
As you'll see, for 6AWG conductor, NM cable is limited to 60C. THHN can go to 75A at 90C. Please stop suggesting that 60A on 6AWG is wrong because it isn't. It is more that just the wire gauge that defines the safe application. Tesla says so and the electrical code says so.
As pointed out by Rocky, you can't use 6/2 NM cable (Romex) for the Wall Connector application and use it at its maximum capability of 60A, but there are other types of 6/2 cable (e.g., THHN in conduit or MC) that CAN be used perfectly safely in this application. Romex is the cable that is limited to 60C; the other types go to 75C or 90C. This is completely consistent with the Tesla manual which says you should use conductors rated for 90C. In other words, Tesla is saying DON'T USE 6 AWG ROMEX, which is also what Rocky said. Neither is saying you can't make a 60A circuit with the Tesla Wall Connector.
All of this is based on the capability of the wire/sheathing and how it is pulled through the house. It is defined by the wire's ampacity and is clearly spelled out in this chart:
Ampacity Charts - Cerrowire
As you'll see, for 6AWG conductor, NM cable is limited to 60C. THHN can go to 75A at 90C. Please stop suggesting that 60A on 6AWG is wrong because it isn't. It is more that just the wire gauge that defines the safe application. Tesla says so and the electrical code says so.
everydaychris
Active Member
Son of a. Ok, thanks for the help. I think JC and confused each other but thanks for clarifying Pluruti
I forgot to respond to this particular point yesterday. The wording they are using in the manual on this point is being confusing and can lead to some misunderstanding. It says to use 90 degree C rated wire. Sure. The thing is, most wire is rated for that by itself. Even the wires that are inside Romex cable are 90 C wires individually. BUT, you don't get to use it at a 90 C rating when it is bundled in that format.
The extra information that is missing here is that there are other temperature and rating considerations that lower the rating capacity, so you do not get to use the current value that is shown in the 90 C column of those ampacity tables for the circuit as a whole. You have to go by the lowest common denominator situation from all the limitations. The main obvious limitations on both ends are that the terminal lugs where wires are screwed in on both the circuit breaker and inside the wall connectors or outlets are only 75 C rated, so that already sets your upper limit, even if you are using wires that are listed for 90 C.
Wanted to update the thread since I picked up my Y and now I able to charge it via the Gen 3 wall charger.
I noticed at 40 amp the charging cable you can feel a warm cable. Based on what I am seeing I would be concerned about the car cable getting too hot at 48 amps. I would be concerned about the charging unit overheating.
It seems to work really well and fast at the 40 amp setting and doesn't overheat.
I noticed at 40 amp the charging cable you can feel a warm cable. Based on what I am seeing I would be concerned about the car cable getting too hot at 48 amps. I would be concerned about the charging unit overheating.
It seems to work really well and fast at the 40 amp setting and doesn't overheat.
everydaychris
Active Member
VaxAce
Member
the Tesla documentation is pretty clear as to cable type etc. I have 3 wall chargers - 2 gen 2 - 1 gen 3 -- all 60 amp - copper.
to OP - I wouldn't pay someone to go to 60 amp - 'just because' - come sown to YOUR requirements and how fast you NEED to have a battery to where you NEED. That all. If you come home from work and plug it in and don't need the car till the next morning - your setup is more than fine. I ran 60 because it was a new implementation in a gutted garage.
to OP - I wouldn't pay someone to go to 60 amp - 'just because' - come sown to YOUR requirements and how fast you NEED to have a battery to where you NEED. That all. If you come home from work and plug it in and don't need the car till the next morning - your setup is more than fine. I ran 60 because it was a new implementation in a gutted garage.
VaxAce
Member
Might be OT but given the knowledgeable posters here I thought it’s worth a shot: if designing a circuit from scratch, is it worth using two (2) 100A dedicated circuits for 2 home charging stations (i.e. 100A for each charger, at 80% = 80A continuous)? Does Tesla even have a device that could charge a Tesla vehicle faster than 48A at home? Thanks in advance!
empiredown
Member
It's not the device, it's the car itself... You're wasting money for anything above 48 amps. Safer? Sure, but that's only 80% as is on the circuit its built for. The Wall Connector only supplies the juice and Tesla is not authorizing anything higher outside of its proprietary SC network. Going forward, I'm pretty certain that will not change and probably doesn't need to in order to implement wider charging solutions for more people with as little impact as necessary.
IMO, some of the drama we're seeing with Wall Connectors is linked to that (stressed systems, infrastructure not up to the load, etc) and the software ratcheting things down or freaking out, accordingly.
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IMO, some of the drama we're seeing with Wall Connectors is linked to that (stressed systems, infrastructure not up to the load, etc) and the software ratcheting things down or freaking out, accordingly.
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What makes you certain that Tesla will not change? Wasn’t the older High Power Wall charger that was compatible with Model S at up to ~70+Amps made by Tesla?
Good gosh, man! It blows my mind people with mansions proposing stuff like this. The main for my entire house is 125A.
No, definitely not worth it. Tesla is not going upward in power levels if you have been paying attention. @empiredown is quite right on this.
Oh, they possibly will, but you seem to be assuming that is upward to higher power. But they have demonstrated from several data points now that they are moving downward in power. Tesla is reducing the power of home AC charging now that the Supercharger network is more built out and faster and more available. They consider that the main substitute for needing really fast home charging.
Wall connectors: Used to be 80A supplied. Now they have gotten rid of those and the new one only does 48A.
Fastest onboard chargers inside the cars: Used to be 80A. Then it was lowered to 72A. Then it was lowered to 48A.
Do you see anything going to higher power? I see the opposite.
Thanks for the response. Dumb question: how is it that the supercharger allows for faster and faster charging on the newest models (i.e. model 3 vs older model S) yet posters keep stating that the onboard chargers inside the cars are getting lowered?
Oh, those are two different scenarios. What we are referring to as a "charger" is the device that converts AC (alternating current) to DC (direct current).
At your house, you have AC circuits, so the wall connectors or mobile charge cables are just passing that AC connection inside the car, and there is an onboard unit that converts the 240 volts AC into the 400 volts DC to directly charge the battery.
In the Supercharger situation, it's not using the AC to DC converter inside the car--that's bypassed. Because there is a really big cabinet outside that has a large stack of several of those chargers. They are doing that AC to DC conversion on a big scale outside the car and then passing the high power DC energy directly into the battery.
