Tesla wall connector question.

[eprosenx]

I have a disconnect and mine is 50a. He said it wasn’t required, but it’s one of those AC disconnects that you pull out the blade part. They are about $10, so why not.

I don’t see 624.43 would apply. It’s 60a and 120v to ground for each phase.

Oh wow, I totally missed the "to ground" part of that code requirement. You are completely right and I am wrong! The paragraph right below that one (which I read first) was talking about "125 volts" and "250 volts" and so my brain was thinking in total potential voltage across the hots. Since 624.43 is "to ground" voltage you are right. So it is not a requirement... It would be for a Wall Connector running at 277v (which is allowed!).

My reason to not want to do it is for "prettyness" since I mounted this on a visible part of the outside of my house. ;-)

 

[Carrera]

I had mine installed today on a 60 amp circuit using setting 9 which is 48 amps. There is no switch as it’s not needed by code. The first charge I saw 44 mph. Is that typical for this setup? I was seeing 4-5 on 110v and 22 using a ChargePoint charger at work so it is a huge improvement.

 

[eprosenx]

I had mine installed today on a 60 amp circuit using setting 9 which is 48 amps. There is no switch as it’s not needed by code. The first charge I saw 44 mph. Is that typical for this setup? I was seeing 4-5 on 110v and 22 using a ChargePoint charger at work so it is a huge improvement.

That sounds totally right! My buddy who tested my HPWC using his model 3 (which is also on a 60 amp circuit) got 41 miles per hour, but we were also messing with the car (AC and all) so yeah, awesome that you are getting slightly better than that! I think that is exactly what it is supposed to get!

 

[davewill]

I had mine installed today on a 60 amp circuit using setting 9 which is 48 amps. There is no switch as it’s not needed by code. The first charge I saw 44 mph. Is that typical for this setup? I was seeing 4-5 on 110v and 22 using a ChargePoint charger at work so it is a huge improvement.

It's certainly a good thing to have, though. That's why I've always been glad my EVSE has a plug. The few times I've had it open, it's a comfort to look down and instantly know it's not live. There have also been times when weirdness has caused me to want to power cycle it, and it would be a drag to have to go to the main panel to do it.

 

[Dana1]

So I did some more research into this and I found a new section of the NEC I was not aware of. Section 625.

Among other interesting tidbits, it has this:

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."

I read that as you can put one of those wire cage covers on the breaker so it can be locked "off" (they cost a few bucks at Home Depot or Platt Electric), but I think this could very much be open to debate as to what type of disconnect they are asking for. I guess it all comes down to your AHJ (authority having jurisdiction). I suppose if your breaker panel is a long way away or not easily accessible I could see the local inspectors wanting a disconnect right next to the unit.

Really though I think it is pretty silly. There are no serviceable parts inside like there are with AC units. If it breaks, you have to replace the whole thing anyway... (and that should nearly never happen) So the value prop of a disconnect switch is dubious in my opinion for most residential installs.

Safety. If you’re replacing/servicing a 60a (plenty to kill you) unit having two barriers is a safety margin for one of them failing (circuit breakers can fail over, admittedly, a long period of time).

 

[Carrera]

When breakers fail they shut off or catch on fire. If you switch it off it's off. I'm willing to bet my electrician's life on it. If it was necessary to have a backup breaker it would be mandatory code here in CA.

 

[eprosenx]

When breakers fail they shut off or catch on fire. If you switch it off it's off. I'm willing to bet my electrician's life on it. If it was necessary to have a backup breaker it would be mandatory code here in CA.

Yeah, that is my experience as well. You can buy "lock off" cages to go over the breakers so that you can literally lock them in the off position with a locking device. That way nobody inadvertently turns something back on for you when you were not expecting it.

 

[jamnmon66]

Just had mine installed today. Get the car Thursday. Is the green light on the wall connector always supposed to be on? Also, can I dial down the amps it draws as it’s supposed to be adjustable or is it once installed it’s set to what it’s set to?

I’m asking because I’m not sure how the electrical aspect works. If it’s a 48 amp circuit on a 60 amp breaker, and I set to charge at say 32, is it pulling 48 but only using 32 or does it only pull what I’m actually using. I’m more wondering about overall load.

Just to clarify, you're only allowed to use 80% of the rating of the circuit for continuous operation. It sounds like you have a 60 amp circuit since that's the size of the breaker. 80% of that is 48 amps. This is the maximum that the M3 can handle (outside of DC charging like a Supercharger). There's no need to make any adjustments in the car. Just plug it in at night and enjoy driving it.

Mine is on a 100 amp circuit which can provide 80 amps continuous. But, as I mentioned, the car can only charge at 48 amps so I have no advantage (until we add a second M3 and a second charger). It charges at 12 kw which is about 48 miles of range per hour. Theoretically, this will charge the battery from 0%-100% in a little over 6 hours. But I set my charge limit to 70-80% for daily driving and I rarely get below 30% so it's usually done in 2-3 hours.

 

[cwerdna]

The HPWC is basically just a smart switch. It passes line power on to the car, along with a signal telling the car how much it is permitted to pull (the signal for how much the car is allowed to pull is set by a rotary switch inside the HPWC, which the installer should have set to match the wiring it's connected to.) The HPWC isn't consuming or transforming any of the power (beyond a trivial amount for its processor and to cycle the relays.)

The car puts a load on the system based on the settings in the car, respecting the limit the HPWC passed it. If the car sees a higher voltage drop when it loads the circuit up, it'll reduce the current it is drawing to hopefully prevent heat buildup elsewhere from becoming dangerous.

And, as more of an FYI for others, the wall connector is an EVSE. The signal telling the car how much it can pull at max is the pilot signal. See Basics of SAE J1772 : Support.

It's J1772 behind the scenes, despite the Tesla proprietary connector. This is why folks have been able to replace that connector w/a J1772 handle to use for charging other J1772-inlet equipped vehicles (all non-Tesla mass-market highway legal consumer EVs and PHEVs in the US sold since late 2010).