hacer
Active Member
If the transfer switch is at the breaker panel, couldn't it switch the hot/neutral for the dryer 6/30, and switch just the hot with direct wired ground to the car charging outlet? What's wrong with that approach?
You can install our site as a web app on your iOS device by utilizing the Add to Home Screen feature in Safari. Please see this thread for more details on this.
Note: This feature may not be available in some browsers.
I understand neutral and ground are bonded at my box. For over 25 years that arrangement has led to no problems with different dryers plugged into the 3-pronged dryer plug. Why would it be problematic to use that wire to connect to the charger (via a transfer switch)?Yes, of course they are. That is the requirement of the electric code. The code specifies that they MUST be tied together there and ONLY there. They are to be separate and not interchangeable throughout the rest of the building's wiring. And that is for good safety reasons. They are both supposed to nominally be 0V potential, but they serve different purposes, and one carries current while the other does not (isn't supposed to).
Well, that goes back into some electrical history of why NEC decided to outlaw those 10-30 type outlets. Dryers have metal bodies, and the old style was kind of dual purposing in "grounding" the body of it with the Neutral wire. That's OK when it's first set up, but if some kind of short or broken wire or something happened behind the scenes somewhere, you could have the body of the clothes dryer still tied to a current-carrying Neutral, but not grounded elsewhere, and when you touch the body of the dryer, you are now the shortest path and get shocked. Separate Neutral and ground wiring through the house prevents that. So that's the why. 10-30 outlets still exist, but they haven't been allowed in new construction for about 20 years.I understand neutral and ground are bonded at my box. For over 25 years that arrangement has led to no problems with different dryers plugged into the 3-pronged dryer plug. Why would it be problematic to use that wire to connect to the charger (via a transfer switch)?
Yes, there are a lot of outlets in a lot of places, and the mobile charge cable has monitoring and safety circuitry to protect you and the car from any issues if the outlet does have a problem. So yeah, that's fine to use existing 10-30 or other types of outlets that are already out there. It's just an electric code thing of what you may or may not be allowed to install new.BTW, I spoke with a charging specialist at Tesla, who felt using 3-wire was fine, and that Tesla made adapters for that purpose. So I guess the company's position is that it is safe, even if it is outdated practice.
Well, there are two basic ways: Get some hard wired device mounted or have an outlet that your mobile charge cable plugs into. There are a few minor pros and cons that are mostly about your preferences, but they accomplish the same thing in about the same way.Also, what is the difference between using an HPWC versus an outlet (several posts above)? Is there more than one way to set up home charging?
The Dryer Buddy is a decent idea that has been suggested a couple of times, because it's all stuff you plug in externally, so there is no wiring and electric code issues. But it would be the question of is your laundry room "in" the house, where you would have to run a cable down the hall and out the door into the garage?I keep pushing the 3-wire arrangement because of the expense (estimate ~$2300) and difficulties to get a new line from one side of the house to the opposite side. It would require external conduit going up the street-view, 2-story brick facade, through the attic, cutting holes in a room's floor, etc. And of course the dryer plug is about 12 inches from the interior wall of the garage.
I'll throw out an even simpler solution. If your daily driving is under about 60 miles, a 110 outlet is perfectly sufficient. That's what we're doing for my wife's Model 3. It adds about 5 mph of range, so 60 in 12 hours. I do have a NEMA 14-50 for my Model S, so I could switch her 3 to that if needed, but so far in three months it hasn't been necessary.
No, it's not heated - it get's cold enough there in the winter that we use it to chill soft drinks/beer etc. Since the OP is in Alabama, I doubt he'd have any problem.Do you have a heated/ insulated garage? Reportedly, 120V has trouble keeping up with heat loss on the S in cold places. Wondering if the 3 does better.
No, it's not heated - it get's cold enough there in the winter that we use it to chill soft drinks/beer etc. Since the OP is in Alabama, I doubt he'd have any problem.
So could I use the Tesla NEMA 10-30 adapter with the mobile charging cable and just plug it into the 3-hole dryer plug? I understand the adapter is supposed to cap the amperage at 24, and for redundancy I could set the limit via the car's software.
I appreciate all the helpful comments.
Sure, that's just fine. That's why the 10-30 adapter exists... All of the hassle is because you are trying to install a "new" 10-30 and that's not allowed under code anymore.So could I use the Tesla NEMA 10-30 adapter with the mobile charging cable and just plug it into the 3-hole dryer plug? I understand the adapter is supposed to cap the amperage at 24, and for redundancy I could set the limit via the car's software.
I appreciate all the helpful comments.
I'll throw out an even simpler solution.
If your daily driving is under about 60 miles, a 110 outlet is perfectly sufficient.
That's what we're doing for my wife's Model 3.
It adds about 5 mph of range, so 60 in 12 hours.
I do have a NEMA 14-50 for my Model S, so I could switch her 3 to that if needed,
but so far in three months it hasn't been necessary.
Just to put it into perspective, if you charged for 12 hours, from 6pm to 6am on 120 V, using your Rate A, summer schedule rates, it would cost $2.52 to charge, compared to $1.47 if you could charge the same amount at the off-peak rates, or $1.05 more. If it costs $2,000 to install 240V/30amp service (per the OP), it would take 5.2 years of charging to justify the cost compared to just using an existing 110 V outlet.I you have a EV discount plan, you'd better charge during off peak using 240 V and at least 30 A.
Charging at 120 V and 12 A all the day will cost you twice as much for the same amount of power delivered.
Thank you for following up, but I apology, I should had mentioned the regular residential rate of $0.28 in California to compare with.Just to put it into perspective, if you charged for 12 hours, from 6pm to 6am on 120 V, using your Rate A, summer schedule rates,
it would cost $2.52 to charge, compared to $1.47 if you could charge the same amount at the off-peak rates, or $1.05 more.
If it costs $2,000 to install 240V/30amp service (per the OP), it would take 5.2 years of charging
to justify the cost compared to just using an existing 110 V outlet.
For me, in New Jersey, we have flat rate all day 14.5 cents to 15 cents /kWh, so time of day doesn't come into effect.
The NEMA 10-30 adapter is available from Tesla and is a direct fit with the old style dryer outlets ... problem solved.So could I use the Tesla NEMA 10-30 adapter with the mobile charging cable and just plug it into the 3-hole dryer plug? I understand the adapter is supposed to cap the amperage at 24, and for redundancy I could set the limit via the car's software.
I appreciate all the helpful comments.