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I have purchased a new Tesla model Y and figuring out options to install a home charger in my garage.

Issue: I live in MA and I do not have a basement or crawl space. My circuit panel is on the ground level in a room adjacent to garage but at least 30ft away from the garage wall. Question: Is there a way to run a wire from panel through the wall and to the garage?

If the above is not possible, I did some research and came up with the below solution. Please advice if I should consider this or what would be most cost effective solution.

Potential solution (need you opinion here) I have my dryer inside the home but adjacent to the garage wall. The dryer is on a 30A circuit with a 10-30 outlet. I am thinking to use a voltage splitter (https://splitvolt.com/products/splitvolt-safety-certified-splitter-switch-nema-14-30-14-50) and use the existing 30A circuit to charge both my EV and also run the dryer. This splitter has the ability to switch full power and also has a safety breaker if my EV tries to draw more than 24A. I think all I have to do is make a hole into the garage wall and pass the 23ft EV charger wire through it. this setup will force me to charge my EV at 24A to protect my circuit and wiring which will give me about 18 to 20 MPH. I am fine with this because I plan to move soon.

Please advice if there are any flaws in this setup Or if you think I should consider any other cost effective option.

This question is probably asked and answered but I can not find it.

Thank you.

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  • Are you planning to use the travel unit EVSE which was provided free with the car? How will you get from the provided 14-50 plug to a 14-30? Or do you intend to use a Wall Connector? Mar 11, 2023 at 0:42

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If you really need 200 miles in a 10-hour charging evening, 300 miles in 13 hours... then I suppose that's one way to do it. Most people don't need such a high rate of charge, so other options are worth considering.

If that seems a little excessive, then you could consider a 20A circuit run fresh from the panel. However you would need to do a Load Calculation on the panel to make sure it can spare the power without overloading the service. This would allow either a plug-in travel unit EVSE (via a NEMA 5-20 plug) or a hard-wired Tesla Wall Connector.

Hard-wiring would avoid the necessity of a GFCI breaker for those people subject to NEC 2020 rules. A GFCI breaker for EV charging is stupid, because that little box you call a charger? Isn't, but what it is is a much better GFCI. (and a little signal generator telling the car the available amps at this connection). And a relay that goes CLACK!


Cutting a pass-through between garage and laundry room is certainly a violation of the building code, because that wall is required to be fire-rated. There are several ways around this problem.

Assuming your dryer circuit is 4-wire grounded, the simplest is to exploit a rule in NEC that says there is no limit to the number of sockets on a 30A general-purpose circuit. See NEC 210.21 and 210.23 (notably the part where it restricts 50A circuits but does not restrict 30A circuits). With a box extension (for the mandatory space), the circuit can simply be spliced and continued to a second socket in the garage, using normal in-wall wiring methods. If all this is completely new to you, a pro can do it quickly, though it's not terribly hard to learn. Note that if you are under NEC 2020, this would require the breaker be upgraded to GFCI, since sockets in laundry and garage require GFCI protection (unless the state has deleted this requirement, which some have).

This requires that you pinky-promise not to run the dryer while you charge the EV. The breaker will enforce this (assuming it is not a Zinsco, FPE or Challenger, types known to be defective). I don't know a lot of people that run dryers after 11 pm, and you can program your car to charge any hours you want.

The second option is that you can place a junction box on both sides of the wall, connected by appropriate in-wall wiring (10/3+ground Romex). In the garage, you install a NEMA 14-30 outlet. In the laundry, you install a NEMA 14-30 or L14-30 inlet then have a jumper cable going to a splitter or the SplitVolt if you want that.

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Using Dryer outlet is perfectly fine for EV charging on NEMA 10-30 plug.

It is already there, fully wired, so you have noting to do just plug in.

You do need Tesla 10-30 adapter for the mobile charger, all set.

It shall give you about 20 miles per hour, or 200-240 miles per charge (dusk till dawn)

However the safety certified splitter you are proposing is garbage.

It has to be UL certified to be legal.

ul

Here is one that is UL listed

smart splitter

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Another solution is to acquire a smarter charger than what Telsa sees fit to provide which has current probes that go around the feed wires of a panel and let it throttle total power draw for that panel.

Using that you can limit the total draw of the dryer+car to 24A continuous because the EVSE will tell the car to throttle down its charge rate when the other load starts drawing current.

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  • There are also boxes that can do such with an existing EVSE although they're more "on/off" than being able to throttle the charger Mar 11, 2023 at 17:37

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