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?
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Building inspector won't approve transfer switch
- Thread starter cwoernle
- Start date
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)?
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?
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 So I guess the company's position is that it is safe, even if it is outdated practice.
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 appreciate everyone's feedback.
gjunky
Trifecta: Solar and both cars are EVs
Did you look at the dryer-buddy mentioned earlier? (Also not affiliated). There is no installation. Just plug in all the parts. This could save you a boat load (frunk load) of money.
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.
So the real answer to that second part of your question--it wouldn't really be "problematic" to just use it the way it is if you were just going to plug something into the existing outlet. It's just an electrical code thing. You can't install a new circuit of that type, so I doubt you could get inspection approval to install something "new" that is wired onto that existing type of circuit.
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.
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.
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 saw you mentioned earlier that the inspector had approved a transfer switch. Can you elaborate on what was approved? This is just a code question of what you are allowed to do, and really your inspector is the only authority you need to convince. If you and he can work out something he will sign off on, that's all you need. It's a dedicated run from your panel, so the issue is about the purpose and connection of that third wire as you switch. On the dryer outlet, it would need to officially be Neutral, but when you throw the toggle switch, it's supposed to officially be Ground for the car charging wall connector. Back in the electrical panel they are tied together, so I don't know what the code would say about this situation or if there is something that can be done that would make it acceptable.
Could a mobile charge cable just be plugged into the dryer plug, or a Dryer Buddy, and I would not need the wall charging unit at all? If so, what added function is provided by the wall charging unit?
All wire has resistance, current through a resistance produces a voltage potential. If you use neutral as chassis ground on an appliance, the appliance will have a voltage on it due to the current flowing through neutral. If you touch the appliance with one part of your body and a ground (water pipe/ other appliance/ the ground) you can get a shock. Worse yet, if the neutral connection fails, the appliance is now at 120 or 240.
Neutral and equipment ground are bonded together at one place and also tied to the earth ground and water pipes at that point. The ground wire normally carries no current so no voltage potential. That makes all your grounded appliances the same potential as the ground you are standing on. Same voltage means no shocks. If there is a fault in the appliance, the current goes through the ground wire, not you.
In the case of a purely 240V appliance (no 120V bulbs or timers) on its own circuit that runs to the main panel (not a sub panel, those have split neutral/ground busses), neutral is effectively the same as ground (and connect to the same bus bars).
Neutral and equipment ground are bonded together at one place and also tied to the earth ground and water pipes at that point. The ground wire normally carries no current so no voltage potential. That makes all your grounded appliances the same potential as the ground you are standing on. Same voltage means no shocks. If there is a fault in the appliance, the current goes through the ground wire, not you.
In the case of a purely 240V appliance (no 120V bulbs or timers) on its own circuit that runs to the main panel (not a sub panel, those have split neutral/ground busses), neutral is effectively the same as ground (and connect to the same bus bars).
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.
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.
I appreciate all the helpful comments.
Oh sure, I was just data collecting and wondering how things were in NJ.
(Do they let you plug in your own car?
)
Uncle Paul
Well-Known Member
People should keep their receipts when installing their charging stations.
At the end of 2017 the Fed extended the 30% Tax credit for installation. Savings up to $1,000 were made available.
There is a good chance it will again be extended for 2018 installations.
At the end of 2017 the Fed extended the 30% Tax credit for installation. Savings up to $1,000 were made available.
There is a good chance it will again be extended for 2018 installations.
Yes. Although it isn't recommended to frequently plug/unplug outlets. They will wear out. Hence the dryer-buddy suggestion.
davewill
Active Member
Sure, that's just fine. That's why the 10-30 adapter exists... All of the hassle is because you are trying to install a "new" 10-30 and that's not allowed under code anymore.
And there will be no need to dial the car down, in fact you won't be able to, since it will already be set to 24a as the highest when plugged in.
UberEV1
Member
Maybe it was already suggested, but what about switching your electric dryer for a gas dryer? Safely frees up the 240V circuit (and you get a new dryer out of the deal).
NeverFollow
Active Member
I you have a EV discount plan, you'd better charge during off peak using 240 V and at least 30 A.
Charging at 120 V and 12 A all the day will cost you twice as much for the same amount of power delivered.
PG&E Residential - Electric Vehicle (EV) rate plans: Making sense of the rates
https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_EV.pdf
Off peak. (11:00 pm - 6:00 am)
Part peak ( 6:00 am - 1:00 pm) (8:00 pm - 11:00 pm)
Full Peak ( 1:00 pm - 8:00 pm)
Rate A: Applies to all applicable customers unless they qualify for and choose Rate B.
Rate A
Total Energy Rates ($ per kWh) PEAK ...........PART-PEAK ..... OFF-PEAK
Summer Usage .......................... $0.45389 .... $0.24986 .......... $0.12225
Winter Usage ............................. $0.32018 .... $0.19794 .......... $0.12503
Rate B: Applies to all applicable customers with a separately metered BEV or PHEV recharging outlet.
Rate B
Total Energy Rates ($ per kWh) PEAK ...........PART-PEAK ..... OFF-PEAK
Summer Usage .......................... $0.44738 ..... $0.24660 ......... $0.12179
Winter Usage ............................. $0.31325 ..... $0.19447 ......... $0.12453
TERRITORY: This rate schedule applies everywhere PG&E provides electric service
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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.
NeverFollow
Active Member
Thank you for following up, but I apology, I should had mentioned the regular residential rate of $0.28 in California to compare with.
(Also to calculate the $2.52 and $1.47 for 12 h, you should calculate the amount of kWh produced per hour)
Pacific Gas & Electric - Tariffs
Residential (MAR 1, 2018 - Present)
https://www.pge.com/tariffs/ResElecCurrent.xls
$0.21169 - Baseline Usage
$0.27993 - 101% /400% of Baseline
$0.43343 - High Usage Over 400% of Baseline
1 H at 120 V x 12 A = 1,440 kWh
12 H (6 pm to 6 am) -> 12 h = 17,280 kWh
Cost: 17,280 kWh x $0.28/kWh = $4.838 and one year (~300 days) $1,451
When using the EV off peak rate of $0.12225 you get:
Cost: 17,280 kWh x $0.12225 = $2.11 and one year (~300 days) $633
Saving about $2.72 a day, after one year (~300 days) you save about $816 / year
So getting the PG&E EV rate seems to be worthwhile.
You mentioned 60 miles a day, so for a year (~300 days) you drive annually ~ 18,000 miles / year
With an ICE typical mileage of 30 miles/gallon and $3.50 a gallon (regular), it would cost $2,100
Also, 17,280 kWh for 60 miles, means about 290 kW/mile or 3.5 miles/kWh which is what was describe in various postings.
What watt hours per mile are you getting on your Model 3? | Tesla
Real world range - New Owners BE PREPARED. | Tesla
No need to get another NEMA 14-50 for $2,000 if you drive 60 a day and can recharge every night.
- Using an existing dryer plug (NEMA 10-30) [and a Dryer Buddy] would provide 240 V and 24 Amps, or 3 hours
- Or simply combining two phases using a 110-120 and 220-240 Voltage Converters & Accessories would provide 240 V and 12 Amps, or 6 hours
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FlatSix911
Porsche 918 Hybrid
The NEMA 10-30 adapter is available from Tesla and is a direct fit with the old style dryer outlets ... problem solved.
Model S/X/3 Gen 2 NEMA Adapters
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