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I am considering installing a circuit splitter product, such as NeoCharge for my EV. The outlets that can be shared are a 30A circuit (dryer), and 50A circuit (for induction cooktop). Both outlets are on the opposite side of the walls adjacent to an attached garage (no HVAC). Is there a code-compliant way (KY USA), to pass the EV charging plug through the wall from the laundry or the kitchen to the garage?

The only installation I found that's close to what I am trying to do is submitted on their website by a user and shown below. Is this an allowed use and what type of wall plate do I need? enter image description here

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  • Why not run cable from the panel to the garage for the EV?
    – jay613
    Oct 16, 2023 at 19:54
  • Expensive option and would need to be done from the exterior on the opposite end of the house.
    – David
    Oct 16, 2023 at 19:56
  • What is that cable portal product in the wall? I have not seen something like that being code-compliant. Maybe it is, do you have a link? The only way I know to do that is to frame out a large enough hole in the wall that the cable is not technically inside the wall. But you mustn't and wouldn't want to do that into a garage!
    – jay613
    Oct 16, 2023 at 19:59
  • @jay613 that's what I thought. Looks as a bit of a hack job. Link: getneocharge.com/products/… Need to scroll to bottom - one of the customer submitted photos
    – David
    Oct 16, 2023 at 20:00
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    That looks like a blank face-plate which someone modified with a hole-saw and then cut it in half vertically. I wonder if it would be 'code-legal' to frame out a pass-through in that wall, maybe 4" square (large enough for the plug to pass easily) ... ?
    – brhans
    Oct 17, 2023 at 2:24

1 Answer 1

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So we see a lot of very bad electrical work being done in connection with EV charging. Partly because this is often the novice's first encounter with anything electrical, other than plugging things into the wall. Naturally the novice gravitates toward plug-in solutions, and here we are busting holes in firewalls to run lumpy cords through. The linked picture is a hatchet job, violating a variety of codes; Neocharge really ought to remove that from their website. *

First, a few unmatters

The obsolete 3-wire dryer circuits are not allowed to be extended, because they don't have a ground wire. ** The good news is if the installer did their job, there may well be a 4-wire cable behind the 3-prong socket. In which case the dryer should be converted to 4-prong; this will be safer all-around and allow safely doing extensions. (that's the other issue with messing with 3-wire dryer splitters). Otherwise, a ground wire can be retrofit to any junction box (or the Grounding Electrode wire) with #10 or larger ground going back to the panel. See 250.130(C) for retrofit ground rules. I wouldn't even use a cheap splitter without a 4-prong dryer outlet.

There's also a Load Calculation issue. Even though you're sharing the dryer circuit, it's possible to exceed the NEC 220.82 Load Calculation because an EV factors at 100% in the Load Calc, whereas the dryer only factors for 40%. HVAC units factor for 100%, so if there's a whole-house A/C near the garage, that might be a better fit for a switcher application.

Now, you will need a "charger" (EVSE really) that knows it is on a 30A circuit and tells the car to take only 24A at the most. The typical "travel unit" provided with the car won't do that; it's for level 1 or charging at RV parks. so it will tell the car "take 32-40 amps". If you're not driving a Tesla, the most readily available solution for this is a wall-mount unit. Almost all of these are configurable to a variety of speeds. They also lend themselves to being hard-wired, which can help with cost of sockets (cheap sockets melt) and GFCI breakers (required on sockets).

EV charging is the hardest load a house will ever face. EVer experience shows if there is any flaw in the wiring, it will be found and made crispy. The #1 flaw is a recently-discovered one: failure to use a torque screwdriver to tighten screws to spec. Turns out electricians do not have calibrated arms, and it matters. This is another reason to open up the dryer circuit wires and check them.

Crossing the wall, option 1: outlet and inlet.

It is legal to install a junction box on or in a wall, run in-wall cable to another junction box only, and place an outlet on one junction box and an inlet on the other box. Then you can have a jumper wire from the inlet in the dryer room to the plug-connected Neocharge or Dryerbuddy. However this still "leaves you hanging" on obtaining a 24A EVSE/"charger". You could buy a wall unit and replace the 14-50 cord with 14-30, certainly.

If your permit issuer will allow this, you may be able to use a 14-30 cord instead of a more costly inlet.

However this installation is going to require the dryer breaker be changed to a GFCI breaker since it serves an outlet in the garage.

Option 2: Similar, but hard-wired.

In this case you'd use a Blackbox or SimpleSwitch instead of the Neocharge, and hardwire everything including a wall unit EVSE, but the dryer would still get a socket. The SimpleSwitch is more costly than a Neocharge, but it sidesteps outlet and inlet, the failure/burn-up points there, and saves the cost of the quality socket and GFCI breaker.

The advantage to any of these smart switchers is they automatically switch. When the dryer finishes, EV charging resumes.

Option 3: No switching, just subpanel.

In this case, you replace the dryer outlet with a subpanel. It has two 30A breakers. One feeds the dryer receptacle. The other feeds a { Receptacle | Hard-wired } EV charge station in the garage. The subpanel has entirely in-wall style wiring (Romex etc.) going in and out of it.

The subpanel can be on either side of the wall, depending on how the wires will reach.

This has the advantage of being the cheapest by far - $70 of subpanel kit instead of a $300++ auto-switch. However it requires manual coordination of dryer and EV charging. Don't dry while charging. That's fine by most people, as they want to run dryers during normal waking hours and charge in the dead of night for the cheap electric rates.

Option 4: Subpanel as a manual switch.

In this case you install the subpanel as above, but add a sliding-plate interlock between the two breakers, so only one works at a time. This is easy to do with Siemens, Square D "QO" or Eaton "CH" using their interlocks ECSBPK02, QO2DTI, or CHML respectively. Adds about $30 to the above.





* If someone does what that photo says, and kills someone, Neocharge is "betting the company" that they will be able to lean on CDA/DMCA Section 230, Safe Harbor provision, and claim that "as provider of an interactive computer service which accepts User Generated Content, we can't be treated as the speaker/source of that content". That seems like a stretch to me, like posting a review of a coat hanger that explains how to do an abortion with it.

** That's not ground, that's neutral. Dryers need neutral because dryers are entirely 120V machines except for the heat source. The same model is made both gas (120V) and electric (240V); with common parts except for a gas-fired heat stove vs. a big resistive electric heater. Obviously several models from that manufacturer will re-use the same heat stove or resistance heater.

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  • @harper-reinstate-monica Thank you so much for the detailed answer. I strongly suspected it was a hack job but wanted to check. I don't think the cables are long enough to reach a new subpanel. What if I were to run another line from 50A J-box to the hardwired wall charger? The induction cooktop is rarely used and the circuit is using Southwire 63950007 6AWG cable. I could install a wall charger with timer (charge say after midnight). Worst case scenario, I decide to cook at midnight and forget to cancel charge - the 50A breaker in the primary panel trips. Could do same with 30A. Am I wrong?
    – David
    Oct 17, 2023 at 23:48

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