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Can I install a 50 amp breaker for both the car charger and the dryer? When I use the dryer I am not use the car's plug. It was 30 amps.

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NO WAY! You probably have 10ga wire to the dryer which is generally good for 30 amps. And now you want to pull 50 amps on the wire/cable? ....with the possibility of someone after you sell the house, runs the dryer and EV charger at the same time, potentially pulling as much as 80 amps on a 30 amp cable!!!!! Run dedicated circuits with appropriately sized wire/cable gauges and appropriately sized breakers.

What you are proposing is a total hack job, not safe, not code legal. If your house burned down and they knew of your setup, you'd probably be denied a settlement.

DO IT RIGHT!

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    Crap, when I re-read my answers sometimes I come across too strongly, I don't mean to be an AH. Still, having to manually, consciously manage an electrical circuit these days is really bad. People expect just to plug things in, have them work, and are safe. Otherwise we're getting back to the electrical system of that old TV show "Green Acres" , ....darn showing my age by the reference! BTW, thanks people for the up votes! Dec 8 '21 at 18:19
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    Stopping someone from burning down their house is not the time to be tentative.
    – ScottyD0nt
    Dec 8 '21 at 19:52
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    @GeorgeAnderson you only said "no way" once, and barely mentioned how likely a burned down house is with this "hack", one could make the case your answer wasn't worded strongly enough.
    – nexus_2006
    Dec 8 '21 at 20:01
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    Not too strong, George. We've had a number of posts recently where an OP stated they knew it was wrong and not to code but would do it anyway. Bottom line you called it like it is, a hack job. It could have been worse, you could have used the same word three times in a sentence... lol stay safe
    – JACK
    Dec 8 '21 at 20:12
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    WOW! Thank all of you for the support of my answer! Didn't expect that. I always try to be a "nice guy" but sometimes I can get pretty emphatic. + to all of you! THANKS! Dec 8 '21 at 20:41
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Option 1: Commission the EVSE at 30A breaker (not 50A)

The amperage on your EVSE is just a setting, because EVSEs work like this.

The dryer receptacles are not made for frequent interchange. However, if your dryer has a 4-pin socket (not 3-pin), and you're willing to swap plugs every single time, then you have one option: When you are commissioning the EVSE, set the circuit breaker size to 30A. This will cause it to charge at a lower rate, but it will be safe and legal to share a 4-prong dryer outlet.

You will need to change the EVSE's plug to a 14-30 type, but cords of that type are readily available cheap.

Option 2: For certain panels, use a "Quadplex" breaker.

This has a 30A breaker and a 50A breaker both, in the space of a normal 240V breaker. The 30A circuit goes to the dryer. The 50A circuit goes to the EVSE.

That means you run a new 50A circuit to the EVSE with new wires to the correct socket (NEMA 14-50 or 6-50). You would need #6 NM or UF cable. If you don't want to pay for that, look for a socket which is labeled "CU-AL" and "75C" and run #6 aluminum cable. Aluminum is fine if you use the goop and set the screw torques correctly.

You must get a quadplex breaker that is compatible with your panel, usually, the same brand. That is not possible on all panels. If you ask a question about your panel compatibility, take photos of it and a clear photo of the panel labeling, we can advise you here.

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  • With option 2, He's have to run new wire for the EVSE so he could just use a regular 50A breaker... right?
    – JACK
    Dec 8 '21 at 13:49
  • @JACK good point, I should explain that... Dec 8 '21 at 18:32
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No, you can't put multiple outlets on circuits for these appliances:

NEC 625.40 requires an individual branch circuit for EVSE.

NEC 110.3 says equipment UL/CSA/ETL Listed Equipment must be installed per the installation instructions which for your dryer likely says it needs to have a separate 30A circuit (like shown here on Whirlpool page 4 and 6).

A 50 circuit would not provide adequate protection for a 30A appliance, an overload of 150% wouldn't trip a 50A breaker.

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  • I agree with most of your posts here, but isn't over current protection for the installed wiring and not the device? The device should have it's own, built in, over-current protection, right? Or am I missing something? Dec 8 '21 at 13:22
  • I think, @GeorgeAnderson, the assumption is that the 30A appliance is installed with #10 wiring on a 30A breaker. Upping the breaker size leaves both the appliance and wiring unprotected. Unless, of course, one can be certain that the wiring is big enough to handle 50A.
    – FreeMan
    Dec 8 '21 at 16:45
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    @GeorgeAnderson: Many devices that are designed to be used with dedicated circuits don't have any internal overcurrent protection, but rely upon the existence of upstream protection. A stove might be designed to be suitable for use on a 30A breaker, but have internal wiring that would survive any fault that wouldn't trip a 40A breaker, in which case it could be used with either size breaker as convenient, but if one had a stove on a 200A circuit, no matter how beefy the wire between the breaker and the stove, bad things could happen if the stove developed an internal short.
    – supercat
    Dec 8 '21 at 19:04
  • @supercat :Agreed, it's hard to know how much internal over-current protection is in a device vs. the circuit supplying it. But think about it, suppose a calrod burner on a range shorted out, but not drawing enough power to trip a 50 amp breaker, melted wires and potential fire would be the result. I just DK enough to comment intelligently, but I would hope that the range would have sufficient internal fusing to protect itself. Maybe I'm just being naive...I just don't know enough about this stuff to comment intelligently. Thanks for your comment. Dec 9 '21 at 2:18
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    @GeorgeAnderson You are mistaken. In-device overcurrent protection is not standard for high-power devices that are required to be installed on dedicated circuits. UL listing requires hooking things up in accordance with manufacturer instructions - if a range says "30A circuit max", you may not put it on a 50A circuit. It has been designed (and tested) to fail safely on a 30A circuit, not a 50A circuit.
    – nobody
    Dec 9 '21 at 3:31

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