I will be installing a NEMA 14-50 outlet/socket for my Level 2 EV charger.

On average, it'll be about one connect-disconnect cycle a day.

To avoid wear, I'd like to install a two-phase switch that will disconnect this NEMA 14-50 outlet. (also it'll be much more convenient to use a switch as pulling this plug might be hard, especially for my wife)

It has to be a two-phase switch, rated to at least 250V / 50 amps. Since it'll be inside of a garage, it doesn't have to be weather-proof.

Spent an hour in Internet, and closest match I found is this - related two-phase switch but this one is only 20amps.

Also on an Australian web site found interesting switch+socket combined: enter image description here - although it would be ideal, I don't expect to find one for NEMA 14-50 outlet.

So any ideas for just a two-phase switch rated for 50 amps would be greatly appreciated. Can be either for surface or flush mounting.

  • 1
    As I understand it, neutral is not typically switched, just like when you have an ordinary 120 V light, only the hot is switched, not the neutral. If I understand you correctly, then it sounds like you are referring to the "legs", not true "phases" (as there would be with a 2 phase or 3 phase industrial service). In which case there are a LOT of options. – manassehkatz-Moving 2 Codidact Nov 19 '18 at 3:49
  • 3
    One more question: Why do you need to disconnect the charger every day? – manassehkatz-Moving 2 Codidact Nov 19 '18 at 3:55
  • 1
    I think you're getting confused about "legs". I believe "egs" in this context refers to what you are calling "phases". Essentially "the hot wires". In my switch example, I was trying to indicate that a normal switch only switches the hot, not the neutral. – manassehkatz-Moving 2 Codidact Nov 19 '18 at 4:24
  • 4
    What you want is a two pole, non-fused switch rated for 50A, or more commonly 60A even. These are dime-a-dozen really, as 60A is a common rating for safety switches and disconnect boxes. – ThreePhaseEel Nov 19 '18 at 4:36
  • 2
    You're using the word "phase"... we prefer the word "pole" or more informally "leg" when referring to household 120/240V split-phase. There's a reason, but in the scope of this question, it matters not at all. – Harper - Reinstate Monica Nov 19 '18 at 7:24

I believe what you need is a safety switch. Based on this table, if you are switching once per day (as opposed to the I suspect common safety switch usage of "once a month or less for maintenance"), I would look for something rated "heavy duty".

A quick search at Home Depot (not recommending them, just an example of a place to search that has plenty of this stuff available) finds a Siemens 60 A Heavy Duty Indoor Safety Switch with Neutral. This is just one example - there are plenty of others from GE and other manufacturers. Look for >= 50 A, with neutral (but not switching the neutral, just passing it through), heavy duty. You can probably save a few $ if you got to an electrical supply house instead of a big box store.

| improve this answer | |
  • 2
    Note that many/most safety switches bond the neutral by default, and will need the bond pulled + a ground bar kit fitted for use on a branch circuit. Also, the safety switch linked is a fusible type, which is going to require a few dummies installed for use as a branch circuit switch -- something that's factory built as a non-fused switch would be less confusing in his applicaiton. – ThreePhaseEel Nov 19 '18 at 4:43
  • Thank you. Plus one-d the answer. Although I should have mentioned previously, safety switch, although does match my criteria above, but is not really an option for me personally as it's an overkill for this application. It would look IMO too big/ too clunky for what I was thinking about. Thanks again though. – Tagar Nov 19 '18 at 4:47
  • 2
    @Tagar I think you'll find that most switches > 20A are designed for commercial/industrial settings or for service entrance or other occasional usage in residential settings (which is how these safety switches are often used). 50A x 2 legs is a lot more than most ordinary homeowners need to switch on a daily basis. Personally, I think the idea of a "big ugly safety switch" in the garage is great! And as long as it is rated for heavy usage, it will do the job (switching daily) just fine. – manassehkatz-Moving 2 Codidact Nov 19 '18 at 4:51
  • 5
    Or use a 60 amp 2 pole contractor (relay) in the circuit and then you can use a standard light switch in the garage to turn it on and off. – Tyson Nov 19 '18 at 10:14
  • @Tyson, that's an interesting idea! Can you post this as a separate answer with some options for relays that can be fit for this task? – Tagar Nov 19 '18 at 17:16

The problem is, the pretty ones you saw there are Chinese junk. You can't safely fit a 50A switch in an Au/UK 1-gang space, it needs more airspace than that to arrest arcs.

This need for a shutoff switch is a common one, and you can use any variety of air conditioner or outbuilding shutoff switches or hot tub mini-panels. In some of them, they are simply a 2-space breaker panel, and the breaker is the shut off switch; a breaker is the cheapest 50A shut-off switch made.

You may use any device rated 50 amps or more; there is no need to match the size of the equipment to the size of the load. The 50A breaker in your main panel will protect your 50A equipment regardless of any higher-rated devices in the chain.

| improve this answer | |
  • great point on AC, hottub switches - as it's a very similar application in terms of current and voltage. I will research that. qq on "it needs more airspace than that to arrest arcs" - I thought that arcing is only dependent on voltage and not current. Voltage potential is what adds electricity to arc through longer air space, not amperage. Thanks. – Tagar Nov 19 '18 at 20:49
  • 1
    @Tagar the kick of an inductive load is a huge factor in sensitivity to arcing. The inductor is trying to be a constant-current power supply, and will push its voltage up toward infinity to continue flowing current. That is why relays, contactors and switches have a separate, much smaller amp rating for ballast/HID (inductive) loads. That signifies its ability to break against a strong inductor. I have a bunch of classic sodium lights with 50 pound ballasts, and finding appropriate relays has been an adventure. – Harper - Reinstate Monica Nov 19 '18 at 20:54

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.