Canadian mobile connector limited to 32A... connector or car?

[conman]

Does Canada have similar electricity supply as the US with 110/220? In our part of the world it's 240V 1 or 3 phase and we're limited to 24A but with 3 phase that gives us a heck of a lot. Apparently there was even more for a while but safety concerns with 32A in the home caused them to limit it to 24.

 

[Rocky_H]

Does Canada have similar electricity supply as the US with 110/220? In our part of the world it's 240V 1 or 3 phase and we're limited to 24A but with 3 phase that gives us a heck of a lot. Apparently there was even more for a while but safety concerns with 32A in the home caused them to limit it to 24.View attachment 253237

Yes, same supply voltages and same outlet types.

 

[smartypnz]

The only other comment is that if you're out visiting others, be sure which version you use for their situation. Maybe keep the 32 amp adapter in the car, and leave the 40 at home, just to be safe.

No reason to carry two adapters when visiting others. Just dial it down to 32A manually.

 

[tga]

There are two different 14-50 UMC adapters, one for Canada and one for the US, with different part numbers (I have both). The Canadian version is labelled "CAN14-50", part # 1059530-00-A. US is labeled "USN14-50", part # 1014324-00-E.

Before the web store redesign, when choosing the 14-50, there was a secondary drop down to select USA/Canada. I chose Canada (I'm in the US) and noted "I am explicitly ordering the 32A Canadian adapter, do not send the US 14-50" on the order. That choice no longer exists. If a US resident wants a Canadian adapter, it may be best to go through a service center to make sure they order the right part.

The web store says the 6-50 adapter is not available in Canada. I suspect they won't sell you a US 14-50 either.

Tesla uses values that are J1772 standard values.

See the "signaling" section of this SAE J1772 - Wikipedia

See "pilot function".

The UMC uses standard J1772 signalling on the car side of the UMC, but the plug side is entirely a Tesla custom design. There is a resistor connected between the ground pin and the 4th pin on the UMC side of the adapter. The resistor value signals the capacity of the plug, and what pilot signal to send to the car.

I believe @TonyWilliams was the first to document the 12/16/24/40A resistor values here: Melted Charging Adapter/Cord

I added the 32A/20k ohm value here (and everywhere else I found the other values listed on TMC): Melted Charging Adapter/Cord

 

[gregd]

No reason to carry two adapters when visiting others. Just dial it down to 32A manually.

Sure, just remember to to so (and/or check what the breaker value is). Keeping the 32A version in the car makes things a bit more "senior moment" proof. Given the bad things that can happen if you get this wrong, the lower rate is probably a better trade-off unless you really need the extra current or have done your homework ahead of time.

 

[TonyWilliams]

Even the UMC with a hardwired NEMA 14-50 plug uses the 9.1k ohm resistor to signal power (yes, we cut another one apart!)

 

[scottm]

Even the UMC with a hardwired NEMA 14-50 plug uses the 9.1k ohm resistor to signal power (yes, we cut another one apart!)

I've wondered about the replaceability of resistors to dial in what you want?

Or, ohms in parallel drop the value, so slapping a second resistor across the first ... I have to refer to the J1772 spec to see what values do what to the max amps.. here I'm theorizing that less R means more Amps

 

[tga]

I've wondered about the replaceability of resistors to dial in what you want?

Or, ohms in parallel drop the value, so slapping a second resistor across the first ... I have to refer to the J1772 spec to see what values do what to the max amps.. here I'm theorizing that less R means more Amps

The resistors in question aren't part of the J1772 protocol; you won't find them documented there. They are used to signal to the J1772 circuitry what adapter is connected, and therefore how much power is available at the outlet. That's all Tesla-proprietary.

 

[scottm]

Betcha the theory is similar. Even if R values are somewhat different.

 

[mknox]

Not doubting what you have, just saying that my understanding of the 32 amp limit is only because there are apparently so many 40 amp breaker/wire setups up there, not because there's a need to go lower than 80% of the breaker value. As others have noted, the trick is to get the "proper" adapter for your setup, which it sounds like you have located.

It's sort of complicated and a number of things happened.

1. Due to some sort of loophole in the law, the UMC was originally considered part of the car, and covered by automotive safety regulations and not electrical safety regulations.

2. There were some overheating and melting situations with the original 40 amp 14-50 adapter which Tesla had to recall and replace with a revised 40 amp adapter containing a thermal fuse.

3. A couple of fires and/or melted equipment came to the attention of the Ontario Electrical Safety Authority (see # 2 above) and I understand they required that the UMC be "listed" and certified under electrical safety standards like CSA or UL-C. Part of that testing and certification led to it being certified for use only up to 32 amps.

It really has nothing to do with 14-50 stove outlets being wired on 40 amp breakers which is legal and common in both the US and Canada. Continuous high loads common to EV charging presents a unique challenge to wiring systems that traditionally are used for intermittent loads that cycle on and off. Since there is no time for a heat-generating loose connection to cool down, overheating is a real and distinct possibility. I believe the Canadian 32 amp restriction is a recognition of that fact.

 

[Rocky_H]

It really has nothing to do with 14-50 stove outlets being wired on 40 amp breakers which is legal and common in both the US and Canada. Continuous high loads common to EV charging presents a unique challenge to wiring systems that traditionally are used for intermittent loads that cycle on and off. Since there is no time for a heat-generating loose connection to cool down, overheating is a real and distinct possibility. I believe the Canadian 32 amp restriction is a recognition of that fact.

This is the part that doesn't make sense though. The wiring systems are made for intermittent loads at the full circuit rating. Requiring a circuit that is oversized at 125% of the constant current level is recognition of that fact already, which is what is done in the U.S. Your explanation is why you would overbuild it some, which the U.S. already does. Why to overbuild it to such an extremely over the top level is what is still pretty confusing.
What seems probably more likely is that this isn't really related to the circuit wiring of the house, which would be OK with 40 out of 50. It seems the Tesla UMC itself is marginal operating at max rate. The cable seems thinner and more flexible than you would use for a 50A circuit in house wiring. I'm guessing it doesn't pass testing to Canadian standards at 40 out of 50A. So to be able to continue to offer it, they probably had to reduce the maximum so that it would operate within a tolerable heat range.

 

[mknox]

What seems probably more likely is that this isn't really related to the circuit wiring of the house, which would be OK with 40 out of 50. It seems the Tesla UMC itself is marginal operating at max rate.

Yes, that is correct. Sorry if I wasn't clear. When the UMC was tested and certified, that is when the 32 amp limitation was made. It had nothing to do with what the UMC was plugged in to.