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Breaker for NEMA 14-30 socket

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Hi

Finally got my first EV. So satisfied except the charging speed at home..
We keep forgetting plugging in right after the ride and at night realize it was not charging. Then it is not charged when I need it in the morning..

So I am thinking to add 14-30 socket in my detached garage which is supplied by double pole 40A CB from the house circuit board.
I guess it will help even if I start charging before bed time.

First question is if NEMA 14-30 with 30A breaker would be good for my garage?
There is a double pole 40A CB in the house main panel to the garage sub-panel.
In the garage sub-panel there are already two 15A breakers for lights and the garage door and wall sockets..
I think 14-30 with 30A CB would be OK but just wanted to get some advice from others.

And the second is whether 14-30 requires GFCI CB.. 14-50 seems like need a GFCI but not sure about 14-30.. or GFCI requirement is for all EV charging regardless of CB size?

Thanks guys
 
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14-30 requires a 30 amp GFCI breaker(assuming the outlet will be used for charging EV's). Any more and the outlet itself becomes a fire hazard(in theory, anyway). There's really no reason to run a new circuit from the main panel. The 40 amp capacity you have at the garage subpanel should be able to handle a new 30(really 24) amp charging load. The garage doors take very little power and for a very short time. The only thing to look out for is if you plan to use a space heater on one of the garage door sockets for hours at a time. 24 of 40 leaves only 16 amps left, and that's not gonna fly if those 16 amps are continuous and therefore really count as 20.

Sure, if its easy and you have the space in the main panel, you could add a 30 amp GFCI breaker there and run the new line to the garage, if you'd like. Make sure your main breaker is sufficient for the extra load(it probably is, but check anyway). In case it isn't obvious, you need to check the main breaker/panel is sufficient even in the case where you are adding the 30 amp breaker to the subpanel.

If you don't NEED the 30(24) amp charging rate, a 6-20 outlet would get you 16 amp/240V charging, and could definitely be put in your subpanel without any concern for overloading even with a space heater running for a long time on another subpanel circuit.
 
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First question is if NEMA 14-30 with 30A breaker would be good for my garage?

Yes, that would work fine.

And the second is whether 14-30 requires GFCI CB.. 14-50 seems like need a GFCI but not sure about 14-30.. or GFCI requirement is for all EV charging regardless of CB size?

By code yes, but if I were doing it, I wouldn't bother with one. GFCIs have been known to trip with EVSEs, they age and need to be replaced every so often, etc. Your use case will have you plugging in a very safe device with zero exposed metal conductors (I am assuming you are using the Tesla portable connector with a 14-30 pigtail adapter from Tesla). So I would just buy a double pole 30A breaker and be done with it.
 
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Hi

Finally got my first EV. So satisfied except the charging speed at home..
We keep forgetting plugging in right after the ride and at night realize it was not charging. Then it is not charged when I need it in the morning..

So I am thinking to add 14-30 socket in my detached garage which is supplied by double pole 40A CB from the house circuit board.
I guess it will help even if I start charging before bed time.

First question is if NEMA 14-30 with 30A breaker would be good for my garage?
There is a double pole 40A CB in the house main panel to the garage sub-panel.
In the garage sub-panel there are already two 15A breakers for lights and the garage door and wall sockets..
I think 14-30 with 30A CB would be OK but just wanted to get some advice from others.

And the second is whether 14-30 requires GFCI CB.. 14-50 seems like need a GFCI but not sure about 14-30.. or GFCI requirement is for all EV charging regardless of CB size?

Thanks guys
My Garage subpanel is fed via a 240v 50A breaker from the house panel. I opted to install a 20amp 240v breaker in the garage subpanel and then added a NEMA 6-20 outlet connected to the 20A breaker. I also purchased a 16amp J1772 EVSC and J1772 to Tesla adapter:

(parts needed for my install)

Amazon USA:


and I keep my Tesla mobile charger in the car at all times, for use on the road.
 
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Yes, it's fine to add a 30A circuit to your 40A subpanel, you can even make it a 40A circuit if you want. And GFCI is generally required on all garage *outlets* regardless of type or usage.

But consider a wall charger instead. It eliminates the cost of an outlet, pigtail adapter, wall-wart & cord hooks, GFCI breaker, box, outlet, cover, and neutral wire. Plus it looks/works better and is easier to install. All you need is some 8/2 Romex, a standard $12 40A breaker, and the charger.
 
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Yes, it's fine to add a 30A circuit to your 40A subpanel, you can even make it a 40A circuit if you want. And GFCI is generally required on all garage *outlets* regardless of type or usage.

But consider a wall charger instead. It eliminates the cost of an outlet, pigtail adapter, wall-wart & cord hooks, GFCI breaker, box, outlet, cover, and neutral wire. Plus it looks/works better and is easier to install. All you need is some 8/2 Romex, a standard $12 40A breaker, and the charger.
I agree 100%.
 
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Hi

Finally got my first EV. So satisfied except the charging speed at home..
We keep forgetting plugging in right after the ride and at night realize it was not charging. Then it is not charged when I need it in the morning..

So you're currently on level 1 charging to a household outlet, but you're sometimes forgetting to plug it in after you get home? You'll need to plug it in whether you have a level 2 or level 1 charging solution.
 
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Yes, it's fine to add a 30A circuit to your 40A subpanel, you can even make it a 40A circuit if you want. And GFCI is generally required on all garage *outlets* regardless of type or usage.

But consider a wall charger instead. It eliminates the cost of an outlet, pigtail adapter, wall-wart & cord hooks, GFCI breaker, box, outlet, cover, and neutral wire. Plus it looks/works better and is easier to install. All you need is some 8/2 Romex, a standard $12 40A breaker, and the charger.
Hmm. I thought 40A would be too big becuase the circuit breaker feeding garage subpanel is 40A
 
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Hmm. I thought 40A would be too big becuase the circuit breaker feeding garage subpanel is 40A

AFAIK, you can still do this by code. Considering how lightly loaded the 40A panel is, it should work fine since the EVSE would only draw 32A anyways, leaving you 16A at 120V for lights, plugs and garage door opener. But yeah, the more conservative approach would be to install a 30A breaker. And I'll re-iterate that hardwiring it to an EVSE is the way to go. $425 for a Tesla EVSE.
 
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Hmm. I thought 40A would be too big becuase the circuit breaker feeding garage subpanel is 40A
40 would probably be fine unless you are using lots of power on the other outlets regularly. There's a decent amount of short-term-overload tolerance built into circuit breakers.

I'll also echo that the HPWC is the right solution.
 
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40 would probably be fine unless you are using lots of power on the other outlets regularly. There's a decent amount of short-term-overload tolerance built into circuit breakers.

I'll also echo that the HPWC is the right solution.
The big problem will occur when the panel main breaker trips and you go out to the car in the morning and it's not charged. Slower, but absolutely reliable charging is a better bet, IMHO.
 
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None of the solutions offered will help if you forget to plug the car in. :oops: I agree that increasing the charge rate is a good idea, but you should consider if you really need to upgrade or maybe just need a daily alarm on your iPhone? ⏰

And welcome to Tesla!
He's charging at 120V, which is inefficient and very slow. It's fine for a temporary solution, but I never recommend it for a permanent solution.
 
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None of the solutions offered will help if you forget to plug the car in. :oops: I agree that increasing the charge rate is a good idea, but you should consider if you really need to upgrade or maybe just need a daily alarm on your iPhone? ⏰

And welcome to Tesla!
However, faster charging will help when he suddenly remembers at 3 in the morning and runs to plug it in. :cool:

On a more serious note, having charging installed so that the plug is right where you need it will also help with remembering.
 
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Hmm. I thought 40A would be too big becuase the circuit breaker feeding garage subpanel is 40A
No, you could put a dozen 40A breakers in that subpanel, all being fed by a single 40A in the main. Look at your main panel for example and you'll see that all the breakers add up to far more than the 150A or 200A feed.

But there is a risk of inconvenience (or worse) as it's bad practice to setup the system such that breakers might chronically trip. So if you find that charging at 32A doesn't leave enough headroom to open the garage door while the lights are on then you'd be wise to dial back the charger current to the next lower level. You wouldn't need a smaller breaker as this can all be done at the Tesla end. That's another advantage to the wall charger in that you can semi-permanently set the current limit to whatever you want, but even with the mobile charger you can do this (somewhat less permanently) from the charging screen in the car.
 
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You have been given a lot of good advice, so let’s run some numbers.

First you will need an outlet. You will need a 14-30 or 14-50, or a 6-50 outlet depending on your choice. The outlet needs to be designed to handle a continuous load so forget about a $15 outlet, you will be looking at something like $80, plus the cost of the box.

You will need a GFCI breaker - $150

You will need a mobile connector, which is $230 and comes with the 14-50 adapter. If you go with the 14-30 or 6-50 outlet you will need to spend another $45 for an adapter.

Let’s add $35 for the Tesla Cable Organizer. Your total is $495-$540

The Wall Connector is $425 and you will need a standard 40-amp dual pole breaker, $15 for a total of $440.

With the Wall Connector you configure it for a 40-amp circuit and it will charge at 32-amps. If you find the breaker trips due to the garage door, etc. you can simply replace the 40-amp breaker with a 30-amp and reconfigure the wall connector to a 30-amp circuit, which will charge at 24-amps. Technically, you would not have to replace the breaker, but it would be a good idea never the less.
 
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With the Wall Connector you configure it for a 40-amp circuit and it will charge at 32-amps. If you find the breaker trips due to the garage door, etc. you can simply replace the 40-amp breaker with a 30-amp and reconfigure the wall connector to 30-amp circuit, which will charge at 24-amps. Technically, you would not have to replace the breaker, but it would be a good idea never the less.

Great analysis. But you wouldn't even need to replace the 40A breaker since the wiring would be sized for 40A. So all you'd do is reconfigure the Wall Connector to output 24A instead of 32A.
 
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