Extension of dryer outlet for EV charging

[IamAllThumbs]

My house has a 150A panel and is too full to accommodate a 30-50A dedicated circuit for an EV charger in my garage.
I'm not sure it's worth the investment in a new panel and routing an EV charger plug, so I'm looking for a legal/code-OK cheaper solution.

I have a 30A circuit for my dryer.

1) My EV is a Nissan Leaf Soul S, so its max charging current draw is 27A. I read that plenty of people use that charger in their dryer outlet, because 27A<30A. While 27A<30A, I understand should apply a 1.25 factor for continuous charging, so 27x1.25 would be 32A.
- is it still OK to charger from the 30A (and if not will the breaker just trip, rather that the house catching fire?)
- I could buy a charger that can be dialed down to a max of 24A, so it would be OK for the 30A circuit, at the expense of slightly slower charging
- I could check the wire gauge between the panel and the outlet, but it's likely sized for 30A, but I could pull new bigger wire and upgrade the breaker to 40A or 50A (with wire to match). The distance between the panel and the outlet is not huge, so both cost and effort should be OK. I'm not sure it if's OK to swap a 30A breaker with a 40A in a 150A panel (keep reading, not talking about operating the dryer and charger at the same time)

2) Now the 240V outlets are not designed for plugging and unplugging all the time (unless I replace it with an industrial outlet) and honestly it's not practical to always unplug the dryer to plug in the EVSE, so I would use a swapping device (something like https://getneocharge.com/products/nema-14-30) that would only current to the ESVE when the dryer is not in use.

3) The dryer outlet is not in the garage, but in the laundry room which shares a wall with the garage. I'm trying to find the right instructions on how to route an extension between the laundry room and the garage (you can't just poke a hole in the wall and pass an extension cord through it). I think the following would work:

outlet in the garage mounted in a metal box -> metal conduit along the garage wall *through* the wall to the laundry room -> metal conduit along the landry room -> metal junction box -> short(3ft?) male dryer plug that will then plug into the load splitter
Use THNN wire of the right gauge in the conduit.


That's a little bit convoluted, so I'd have to weigh that against the cost of a panel upgrade and routing a dedicate 30-40-50A to the garage (the Leaf will only draw 27A when charging, but if I invest in the works, I will likely size it for a 50a circuit in case I get a different EV later)

I feel comfortable with doing the work described above myself, I haven't looked at what it would take to replace the panel on my own, but probably something I wouldn't do (I've installed a 30A subpanel in the basement off the main panel but I've never dealt with the main supply to the house)

 

[PJB12]

Hi IAmAllThumbs,
Congratulations on your new car. I hope you enjoy it for many years!

One Big Glitch in Your Plans-
Unless the code has changed since my last update class, and assuming that your area is covered by NFPA 70; Article 210.17 requires that the EV charger be a dedicated circuit. No other receptacle outlets (or other loads) can be on that circuit. Part of the reasoning for the rule is that this is done to ensure that the circuit won't be overloaded. Circuit breakers do sometimes fail to open. (In your case, operating the clothes dryer while the car is charging.)

Work Around To The Full Load Center Problem-
Can you install Tandem (sometimes called "Piggy Back") circuit breakers to make spaces available for a new dedicated 40 amp circuit for your charger? This is commonly done and is less expensive than installing a sub panel.

Some load centers won't allow the use of tandem circuit breakers and some will. Some allow them in certain spaces.
From the NFPA 70: “A panelboard shall be provided with physical means to prevent the installation of more overcurrent devices than that number for which the panelboard was designed, rated, and listed.”

As an example, the main load center in my house has 24 spaces, but is designed, rated and listed for 42 overcurrent devices. Therefore I can use tandem in any space. A sub panel I have has 12 spaces and is designed, rated and listed for 12 overcurrent devices. i can not use tandem (without cheating and removing the rejection tab which I do not recommend). The garage panel has 8 spaces and tandems are allowed in 2 of the spaces.

You will have to research the model of your load center to find out if tandems are allowed.


How To Tandem-
Choose 4 single-pole circuit breakers. Replace them with two tandem circuit breakers. In the now empty two spaces, install your 40 amp circuit breaker for the EV charge. If the circuit breakers are not the same amperage, you can get mixed 15/20's (One half will be 15 and one half will be 20 amp) Each half of the tandem will provide full load current to its load. The bus bar is rated 150 amps, so there is no problem there. (You cannot do this with AFCI or GFCI circuit breakers as there are no tandems for those.)

One Word Of Advice-
I very much advise that you do this work under a permit& with inspection(s). Many jurisdictions allow homeowners to obtain very inexpensive permits for electrical work.

The primary reason is that should there ever be a fire or injury, if the job was not done under a permit and with inspection approval, the insurance company is under no obligation to pay any claims. Unfortunately, even if the fire or injury had nothing to do with your new work, the insurance company still has an escape. (I have often been used as an impartial witness in tort and arbitration cases. I have seen many examples of a claim being dismissed for a fire or injury because totally un-premitted work was discovered, thus rendering the insurance policy void.)

The second reason is to have a second person look at your work (the inspector). Something you missed or could have done better may be seen and advice for correction will be given.

I hope this post is helpful. Be sure to let us know how you proceed and how you like the new car!
Paul

 

[IamAllThumbs]

Thanks for the answer. The splitter device i reference will.only allow one device (dryer or EV).to operate at once. One side (the dryer) gets priority.

I have have several 15 amp tandem breakers (2 circuits in one breaker slot). I will take a better look at my panel and see if:
a) I could create more room for another 30A
b) I'll read up on how you decide your panel has reached capacity

And I would absolutely get a permit and inspection for all the reasons you mention. When I installed a sub-oanel.jn the basement years ago, the inspector complimented my wiring.

 

[IamAllThumbs]

Yikes! It's worse than I remember. Doesn't look like much room here.
I also need to trace and label the existing circuits because most of them are so faded you can't read and maybe they're not longer valid.