3 phase 20A cabling for home charging

[boshk]

I live in an apartment, sharing underground parking.
I already requested installation of my Wall Connector, Gen 2 only in Hong Kong.
Car is 2016 MS 75D, according to EV-CPO, it has High Amperage charger upgrade.

The management of the estate has stated, only 3 phase 20A cabling from their power grid.
Does this mean the Circuit breaker is 20A?

What can I realistically expect to see when plugged in? 20/20A, 20/32A, 20/40A or something lower than 20A?

I read the Wall Connector manual, do I need to insure electrician sets the Rotary Switch position to 20A?

 

[David.85D]

Houston, we’ve got a problem.

the Wall Connector is single phase. You can’t just connect it to 3 phase wiring. Your electrician should know what to do - there are phase converter transformers available. Maybe $1000 plus installation. Depends on the load rating.

if it’s a 20A circuit, you should be setting the wall connector to 80% of that (max) so, 16A.
Pretty low charging rate.

maybe pay to have larger single phase wiring installed?

edit: I only know the specs for the US wall connector. The version sold in other countries _may_ support 3 phase. Don’t know...

 

[JRD1]

OP is in Hong Kong which uses a different version of the connector.

In this manual (from Second Generation Wall Connector Installation)
https://www.tesla.com/sites/default/files/pdfs/wall-connector-eu/20161208/tesla-32a-wall-connector-installation-manual-en-AU-v2.pdf
It includes instructions for 3 phase connections.

Don’t have 3 phase here so no clue on how it works but I seem to recall reading somewhere that 20A on 3 phase is not really that slow.

Might be good to look in the regional sections lower on the main page for more specific answers.

 

[boshk]

Thanks, I did look at the Hong Kong region stuff but its pretty 'inactive'

I did see a video made in 2014 about a HK Tesla Wall Connector and the guy actually showed the manual, it did say 20A circuit, max charging rate in car 16A but I cant find the actually reference anymore.
It was talking about Single phase and Split phase, 50A max.

If it is maxed at 16A 3-phase, is there anyway to get an estimate of charge rate? better than nothing I guess or driving to a supercharger and do the Pay-as-you-go

 

[boshk]

So they installed the Wall Connector Gen 2 (32A Three Phase)
Park lot Circuit Breaker is 3 Phase 20A

The Tesla HK Approved electrician company installed it and set the Rotary Switch to 6. #6 is 20A, (#5 is 16A).
Official manual says 'set Rotary to what is supported by Circuit Breaker' , Support page states otherwise.
Called Electric company, they said its 20A #6.
Waiting on Tesla Sale agent reply.

What problems (if any) will I encounter if the Wall Connector Rotary Switch is set to the same Amps as the Circuit breaker?

I've attached photos
i) actual Rotary switch
ii) manual reference
iii) Support reference

 

[David.85D]

It’s not great, but the worst case is that it trips the breaker. just weird that the power company is ok with that. The breaker (and wire, plug, etc) should be sized for slightly more current than expected. Not an exact match.

Reality is that the car manages the current and ramps it slowly so you won’t have the spike in current typical of starting motorized equipment. That breaker shouldn’t ever trip at 1x rated current or even 1.1x rated current. At 2x it should trip in around 10 seconds (varies) and by 3x rated current should be sub-second.

 

[David.85D]

How much juice does the car get? You should be able to tell from that if they’ve built the safety factor in or not.

 

[KalJoMoS]

I would set it to #5 as this line seems not to be solely for your connector. You would still get plenty of juice and would not needed to run to the junction box for setting the breaker on again. I have it set to #2 as my main is only 16A (3 phase) and it still is better than UMC. I think you will get something around 55km/h

edit: you can test it yourself, on the car menu select display and switch between energy or distance on battery section. Doing so gives you data how big is the power consumption and interpretation in km

 

[boshk]

It’s not great, but the worst case is that it trips the breaker. just weird that the power company is ok with that. The breaker (and wire, plug, etc) should be sized for slightly more current than expected. Not an exact match.

Reality is that the car manages the current and ramps it slowly so you won’t have the spike in current typical of starting motorized equipment. That breaker shouldn’t ever trip at 1x rated current or even 1.1x rated current. At 2x it should trip in around 10 seconds (varies) and by 3x rated current should be sub-second.

Thanks David
-I don't have my car yet, should be in the next few days
-I asked because power supply to Wall Connector isn't turned on yet, figured I would have time to change it myself
-Asked Tesla tech and same as you, they said it should not matter, I would never get the full 20A from the cable anyway due to my MS.
They said car limits to 16A and like you, it ramps up slowly.

 

[boshk]

I would set it to #5 as this line seems not to be solely for your connector. You would still get plenty of juice and would not needed to run to the junction box for setting the breaker on again. I have it set to #2 as my main is only 16A (3 phase) and it still is better than UMC. I think you will get something around 55km/h

edit: you can test it yourself, on the car menu select display and switch between energy or distance on battery section. Doing so gives you data how big is the power consumption and interpretation in km

thanks, will do when I get the car in a few days.
curious why yours is set to #2 8A right? I would have thought it would be #4 at 13A (80% of breaker line)

 

[KalJoMoS]

Just my personal choice as these 3 phases are shared by my house, it will draw app. 6kW on this setting so if you set it to 16A this would be double.

 

[ljwobker]

Some thoughts...

• Is that circuit shared, or dedicated for use of the charger?
• If it's dedicated, you set the current draw to whatever the rated (by local code) limit is for the circuit
• If it's shared, you have to figure out what the max you want the car to draw is (which may not be easy) and set either the car or the wall charger to that value. In most cases I've seen of you cannot run a circuit that big other than to something dedicated, but I certainly don't pretend to know all the cases.
• Just because a building has 3-phase power does NOT mean that a give circuit is run with all three. It's common to split these somewhere before providing the "end user" with a circuit.
• In the USA, residential 3-phase deployments are very rare, but they're reasonably common elsewhere. I would totally believe that the building drops you all three phases, but I'd also believe that they're only dropping you one.
• In North America, the code says you have to de-rate the circuit by 80% for continuous loads, which is where the "choose 16A even though it's a 20A circuit" comes from. In parts of the world where this de-rating is not required, you can safely set the current draw to the rating of the circuit. I don't know HKG codes, but I'd guess the draw can match the circuit.

If they've dropped you all three phases and the wall connector is configured for that, a 3-phase/20A circuit (400V nominal or 230V phase) is roughly 14KW of apparent power. The wire colors I see in your photo above (Brown/Black/Gray/Blue) match the standards for 3-ph power in that part of the world, so I'm *relatively* certain you're wired up for all three phases. What to set the current to depends on the local electrical codes: "are you allowed to set the current to the nominal rating of the circuit, or do you have to de-rate it?"

 

[boshk]

Well, finally got my car and wall connector was installed.
2016 75D
16A Three Phase 220-240V

Charge rate is around 45-50 km/hr.
90% gives 321km
That works out around 9.5-10.2kWh

Trying to find how it can display kWh instead of dist/hr