About 2 years ago my electrician installed an EV charging outlet in my garage. He installed a SquareD D QO 50-amp breaker and ran about 25 feet of 6-gauge cable which terminated in a 14-50 outlet.

After considering options for quick and easy heat in the garage I would now like to also use that outlet for an electric heater. It would not be used to provide regular heat to the garage but would be for sporadic card nights and other man-cave purposes- probably 20 times a year.

I plan to use the following heater, as I have one available for only $140.00:

Dr. Heater Dr. Infrared DR-910M 10000-Watt 240-Volt Heavy-Duty Hardwired Shop Garage Heater


I plan to attach this this cable/plug (or something substantially similar) to the heater instead of hardwiring:

15Ft 50 Amp Extension Cord 250V 6/3+8/1 Gauge Heavy Duty Power Cord, NEMA 14-50P with Portable Handle


I have tried calling and texting the electrician to get his opinion if this all pairs up properly, but I have not heard back from him. He was an older gentleman I have used a few times and I hope all is well with him. I am normally not hesitant to hire out for my electrical jobs but it appears the only DYI task I would have to do is attach the cable to the heater.

I have also heard concerns about the risks of causing outlet damage by plugging and unplugging a 14-50 plug. I don’t want to use a simple pigtail that would leave open the risk of carelessly using both heater and charger at the same time, so I am considering this splitter if plugging and unplugging is ill-advised:

Lectron NEMA 14-50 Socket Splitter


Can anyone give me feedback as to whether the heater, breaker and cable/plug are compatible for my purpose, and if you think it would be wise to invest in the splitter I referenced?

Last thing- the cable is 4-wire and the heater has a 3-wire connection set-up. Would I just cap off the neutral in the cable?

Thank you very much in advance.

  • 3
    Did you note that the Instructions cdn.shopify.com/s/files/1/0557/0356/8589/files/… which are part of the UL Listing specify a 60A breaker? A 60A is consistent with the NEC requiring 125% for most heating applications. A 50A breaker at 41.66A would probably not trip, but NEC 110.3 specifies complying with UL. Sep 22, 2023 at 2:58
  • I didn't notice that, I just saw a few Amazon reviews that their electrician installed a 50 amp breaker and things were good, and one review tested the draw at under 40 amps. Should I be concerned with it being borderline? Is tripping the breaker likely the worst case scenario? Also, I read somewhere in my research that the NEC 125% requirement is only for a hard wired application, not that there can't still be safety concerns. I appreciate you pointing this out, I'm wondering if I should find a 7500 watt heater.
    – Jimmy
    Sep 22, 2023 at 3:22
  • Actually NOT tripping the breaker is by far the worst case scenario. Because a non-tripping breaker on an over-provisioned circuit is what leads to wires catching on fire. You could run a nominal 41A (this unit) on a 40A breaker with 8 AWG NM cable. The breaker might never trip (41A being < 5% off nominal limit for a 40A breaker) but your cable will absolutely not be up to the task of running that much power continuously. Sep 22, 2023 at 14:31
  • Thanks, though since my cable is 6 gauge and the breaker is there to protect the wire from overheating, with a 50 amp breaker and the 6 gauge isn't the possibility of overheating the wire negligible?
    – Jimmy
    Sep 22, 2023 at 15:19
  • My point wasn't that you currently have 8 AWG cable. My point was that "not tripping a breaker" is not equal to "safe", and in fact can be quite the opposite. Sep 22, 2023 at 15:27

3 Answers 3


Another option, also considering the comment on the question by NoSparksPlease about the heater being too much for the derate required for the 50 amp circuit:

  1. Install a sub-panel instead of the 14-50 outlet. Get a 200-amp panel with plenty of spaces, because you'll be wanting another EV station or a set of woodworking tools that need 240V, etc down the road. You can also hard-wire your EV to the subpanel instead of using the 14-50 outlet. This should save the need for a GFCI breaker in your main panel feeding the outlet, if I have read the experts here correctly. Panels with current ratings higher than the breaker feeding the panel are OK, and all you'd have to do to increase the current to the panel is replace the feed cable and feed breaker, after the whole-house load calculation.

  2. Get a mini-split instead of that heater. Much less current usage, much more efficient, and AC for the summer card parties. Note that the mini-split will require either the subpanel or another run of cable to the main panel, since it will need a much smaller circuit breaker.

  • I appreciate the input but you just took my cheap, safe heat plan from $200-400 to thousands.... I just want to safely run a heater from the existing rig.
    – Jimmy
    Sep 22, 2023 at 13:00
  • 1
    Power for a 10000 watt or even 7500 watt heater will hardly be cheap. And you won't be able to charge the car while the heater is running. Per @NoSparksPlease's comment you can't run the 10000 watt heater safely with the circuit as is. And no AC in summer. Sep 22, 2023 at 13:57

Pick two: cheap, safe, or easy.

The cheap/easy path to go down is to find a 10kW electric heater that can go on a 50A circuit. Either buy one that already has a 14-50 cord and is meant for portable use (I found a couple for about $1k) or buy one and put on a nice long cord (looks like $300-400 for the unit and $100 for a quality long cord). The 14-50 outlet will eventually wear out and need replacement before it starts a fire. Given your ~20 uses a year, that's maybe every three or four years, though honestly that's more of a guess than a guideline. This path could be made a bit safer by spending the money to pick up a Neocharge or your proposed Lectron device so you could leave everything connected.

The safe/easy path: like other people suggested, install a mini split, or a new circuit for your heater. This won't be cheap but it will be safe and it's easy to get done.

And finally the cheap/safe path: learn how to do the electrical work, install either a subpanel or an additional circuit for whatever heater you want that fits in your load calculation. If there's room in your main panel, running a 30A circuit for a 5kW heater should be not much more complicated than running any other simple circuit.

  • Thanks, and in regard to the Neocharge/keeping everything connected I had linked the Lectron socket splitter that serves the same purpose. I am looking now at the option of a 7,500 watt heater for which the existing 50 amp breaker should work.
    – Jimmy
    Sep 22, 2023 at 15:17
  • I chose the Lectron because it seems that it does block out one load- from the product page: "PRIORITIZED POWER SUPPLY - The NEMA socket splitter only sends power to one terminal at a time, and switches once the EV plugged into the charger in the primary socket is fully charged." Did you see something that indicates it does not? I am going to email the company for clarification
    – Jimmy
    Sep 22, 2023 at 16:36
  • Further re: the Lectron splitter, these guys do a nice job explaining it on youtube here youtube.com/watch?v=pgeZZ3hmv1c
    – Jimmy
    Sep 22, 2023 at 16:57
  • Basically one outlet is primary, the other secondary, and the unit with not send any power to the secondary if whatever is plugged into the primary is drawing power. Essentially if you plug the heater into the primary it will shut off the power to the secondary even if the car was charging. Pretty nifty.
    – Jimmy
    Sep 22, 2023 at 17:02
  • Thanks again for your input
    – Jimmy
    Sep 22, 2023 at 18:34

It is correct that a high power plugs do not like been plug/unplug often.

The splitter would do exactly that - SPLIT.

Your 50 Amp circuit remains to be 50 Amp and that means you can not charge the EV and run the heater at same time, since the power consumption would be higher than 50 Amp and trip the breaker. Your 10kW heater would use 40 Amps, leaving nothing for the EV.

However there are devices that would actually (internally) SWITCH from one outlet to the other.

  • You’ve missed the biggest problem, which is that the heater requires a 60A circuit. It may not be used on a 50A circuit.
    – nobody
    Sep 22, 2023 at 14:38

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