208V charging?

[pepperoni]

Since there are 3 wires you should technically have a 6-50 outlet instead since that uses only 3 wires. There are 6-50 adapters available.

Not sure what this means in terms of code/compliance/insurance/etc but something to keep in mind.

The electrician originally wanted to install 6-50, but I insisted on 14-50 since it seems to be somewhat of a standard now for mobile connectors. In fact, the Ford mobile connector only supports 14-50 for a 220v outlet. (I was cross-shopping the Mach-E, which is how I learned this odd fact.) I know the neutral is unused, but standards don’t always make sense. Maybe the thought is that people are more likely to encounter RV outlets when traveling with their mobile connector.

The conduit is being used as a ground, which is why you only see three wires. Neutral and ground are definitely connected according to my ohm meter, and the green wire from the outlet is connected to the metal outlet box.

 

[pepperoni]

It's hooked up to ground, but likely the installer meant it to be a neutral (notice it's tagged white).

Or it could be like you're saying and the neutral pin at the plug isn't hooked up to anything - in which case, I agree, switching to a 6-50 would be the best option.

That is the neutral wire you’re looking at. It doesn’t really bother me, since I’ll never use the neutral. Not sure how much it matters anyway since they both go to the same place.

 

[STS-134]

Thanks everyone, I learned a few new things from this thread! First, it is not uncommon for densely packed residential units (like my townhouse) to each receive two out of three connections to a 3-phase power. In fact, in my learnings elsewhere on the internet, most of NYC’s residential units are powered this way. Apparently my neighborhood in Santa Clara, too. Second, @nwdiver points out that it is easier (cheaper?) this way for the electric company when installing transformers in a neighborhood with attached units.

I guess now I’m feeling a bit shortchanged, knowing that my oven could be heating faster and car charging 15% faster had I been on a 240v system. Ignorance was bliss.

Well if you really want to charge your car at 240V, you can use a buck & boost transformer to boost the voltage. This one should be able to charge any modern Tesla from 208V at 240V: Larson Electronics - 1 Phase Buck & Boost Transformer - 208V Primary - 240V Secondary - 62.5 Amps on Secondary - 50/60Hz

If you want your oven and dryer to heat faster too, you'll need a neutral (dryers often use the voltage between one phase and neutral to run the drum motor). So you'll need a center tap on the secondary, as well as a transformer with more capacity. Like this one: Larson Electronics - 50 kVA 3PH to 1PH DOE Efficiency Transformer, 208V Wye Primary, 120/240V Secondary, NEMA 3R, Ventilated, 60 Hz
You could then create your own 240V split phase subpanel and attach all of your 240V loads to it.

 

[GMVan]

Condominiums, townhouses and apartments require 3-phase 208v to power heavy equipment such as elevators. You will never get 240V single phase in these properties because you would then need starter motors for the equipment.

I'm not sure it would be a good idea to upconvert from 208v to 240v, what matters for charging is the kW. The 208v/32A (on a 40A circuit) is delivered to the vehicle which upconverts to the internal DC charging voltage anyway. Depending on the Tesla model you need 350V to 480V of DC power to charge the battery. Adding 240V voltage conversion equipment just increases the conversion losses and cost.

Some non-Tesla chargers only work at 240V. In that case it might be better to buy a replacement charger that works at 208v instead of upconverting. If you are supporting lots of people using your outlet and you want maximum compatibility then that could be a good reason to upconvert.

 

[Rocky_H]

Some non-Tesla chargers only work at 240V. In that case it might be better to buy a replacement charger that works at 208v instead of upconverting.

I don't think that is ever true. Since most commercial properties like malls and shopping centers and apartment complexes are on 208V, it is abundantly common and no equipment manufacturer would be that dumb to design their products they are trying to sell to be incapable of using that.

 

[Genie]

I don't think that is ever true. Since most commercial properties like malls and shopping centers and apartment complexes are on 208V, it is abundantly common and no equipment manufacturer would be that dumb to design their products they are trying to sell to be incapable of using that.

I think people forget the EVSE is a connector, not a charger. All it’s doing is connecting the power to the car’s charger and doesn’t care if it’s between 208-240Vac

 

[Rocky_H]

I think people forget the EVSE is a connector, not a charger. All it’s doing is connecting the power to the car’s charger and doesn’t care if it’s between 208-240Vac

And that's a pretty easy span to design for. Most equipment I see for these levels of things list their expected input voltage range as 200-250V.

 

[unk45]

Thanks everyone, I learned a few new things from this thread! First, it is not uncommon for densely packed residential units (like my townhouse) to each receive two out of three connections to a 3-phase power. In fact, in my learnings elsewhere on the internet, most of NYC’s residential units are powered this way. Apparently my neighborhood in Santa Clara, too. Second, @nwdiver points out that it is easier (cheaper?) this way for the electric company when installing transformers in a neighborhood with attached units.

I guess now I’m feeling a bit shortchanged, knowing that my oven could be heating faster and car charging 15% faster had I been on a 240v system. Ignorance was bliss.

Not just NYC. Everywhere in US multi-residence power systems tend to be three phase, supporting electrical systems serving multiple units, townhomes, condominiums, and many data centers also. So 208v is a common US norm.
Further since we all know that BEV charging is a continuous load:
"First is the definition ofampacityfound in Article 100. Ampacity is “The current in amperes that a conductor can carry continuously under the conditions of use without exceeding its temperature ratings.”

Next is the 125% requirement in 210.19(A)(1) and 215.2(A)(1): “The minimum feeder circuit conductor size,before the application of any adjustment or correction factor,shall have an allowable ampacity not less than the noncontinuous loads plus 125 percent of the continuous loads” (emphasis added). This requirement ensures that conductors and overcurrent devices are not operated continuously at over 80% of rating." source: IAEI

For that reason the maximum draw for a 208/30 outlet, the typical multi-unit-building average outlet, will be 22 amps. In common use typical actual draw is more likely to be about 200/21 or so.

BEV drivers tend to be upset about that. However, having had all my three Tesla's living happily with 208/30 rated, actual draw usually 200/21 or a little less, I have never had a problem. Why?

Simple, even when I drive >200 miles round trip, my cars always arrive with >20% SOC, and charge overnight easily to ~90% which I rarely exceed, or even 100% which I do when setting off on a very long trip. Faster charging really is not necessary for me.

Back in 2014 when I was taking delivery fo my new Model S P85D I was obsessed to find a way to get 240/60 at a minimum. Honestly, useless, because 208/30 nominal is always good enough and also generates less waste heat than would higher amperage, so is really more efficient. Of course were voltage to be higher, that would improve efficiency, but amperage not at all. For anybody who resides in any 208/30 normal outlet, using that without change saves money and simplifies the installation.
If you really want more amperage and if your breakers are factory made as parallel and ONLY if actually built as a pair then you can get 208/60. Your panel does have dualed breakers but the panel seems full so unless you are changing the panel anyway this would be an expensive option.