14-50r NEMA in series install question

[Vaggeto]

Hi all,

I have a sub-panel circuit breaker running outside with a 50amp breaker from the main and in the sub-panel . From there there are is a 30amp out and 20 amp out.

This is mostly for some outdoor lighting and outlets that rarely get used. The sub-panel is in a really convenient place to charge a 2nd electric vehicle occasionally. I am wondering if just prior to the sub-panel I can install an outdoor 14-50r NEMA outlet and then continue on to the sub-panel? Essentially installing the 14-50r outlet in series with the sub-panel?

I realize if I were to charge a car and also utilize a lot of power from the sub-panel circuits, the main 50amp breaker would trip but I'd be okay with that.

I don't see any outlets which have an input and output like typical 15-20amp 110/120v outlets do so I'm guessing not but I figured I would ask.

Thanks!

 

[Rocky_H]

Your plan is a no-go.

Texas is now on the 2017 version of NEC. The 2017 version added (or expanded) a big section 625 about charging electric vehicles, and one of the specific changes that is iron clad says that ANY outlet that is being installed for the purpose of charging an EV MUST be on a dedicated circuit--nothing else attached. It also requires a GFCI breaker for those too.

Unrelated, but yeah, any kind of 240V outlet is built to be kind of "end of the line" for wiring and doesn't have a pass-through like the dinky 120V outlets.

 

[Sophias_dad]

Ya... can't do it.. but if there's breaker-space, you could put a new breaker in the subpanel and feed a new 'dedicated' circuit for the EV.

 

[user212_nr]

Can you take a picture of the sub-panel breakers?

If you have a 30A breaker, maybe you already have a 30A outlet which you can use to charge the car. 30A is way too much for outdoor lighting, unless you have a sports arena or something.

30A is a lot at 240v and people only do the 14-50 because they can, not because they really need to.

 

[Vaggeto]

Thanks for the replies!

Here is a picture of the sub-panel:

There is a 50 in, 30 out, 20 out, and 20 out.

The 30amp out is going to some very power hungry lighting for a "field" out behind our home. It's been a few years since I tested the exact wattage those lights use, but I think it was in the range of 5,000 watts. I'll likely replace these with high power LEDs at some point if they will be used more often. They only turn on from a manual switch that's near the lights and are extremely rarely used.

I like the 30amp idea with a 14-30 outlet. Since this would only really be a backup charging location, so I would be fine with a 30 amp outlet being installed instead of 50amp if it's the only practical option. It also looks like the 30amp breaker allows for a "double tapped" circuit, which would allow that run. I also see this might not technically be to code if it's being installed for the purpose of charging an EV. There are lots of other uses for this type of outlet though

 

[user212_nr]

Thanks for the replies!

Here is a picture of the sub-panel:

There is a 50 in, 30 out, 20 out, and 20 out.

The 30amp out is going to some very power hungry lighting for a "field" out behind our home. It's been a few years since I tested the exact wattage those lights use, but I think it was in the range of 5,000 watts. I'll likely replace these with high power LEDs at some point if they will be used more often. They only turn on from a manual switch that's near the lights and are extremely rarely used.

I like the 30amp idea with a 14-30 outlet. Since this would only really be a backup charging location, so I would be fine with a 30 amp outlet being installed instead of 50amp if it's the only practical option. It also looks like the 30amp breaker allows for a "double tapped" circuit, which would allow that run. I also see this might not technically be to code if it's being installed for the purpose of charging an EV. There are lots of other uses for this type of outlet though

There are lots of options you have to work with there, no sense in speculating all the different possibilities. You don't want to rely on the breakers to trip, but you can turn them off or install toggle switches.

Also, there is probably no need for the 50A breaker backfeeding the panel, as you would have 50A at the main panel already. Move those wires to the regular lug nuts and you can install another 30A breaker. Not to code obviously as it is too much power, but you can leave the other 30A off and still use the 2 120v circuits.

 

[Sophias_dad]

I don't know the code requirements for a subpanel like that. I don't really think that it would be inappropriate to move the input wires to the power lugs and install a 30 amp breaker for the EV. It would definitely be a bad idea to use the same 50 amp breaker as an output, because then the EV could use the entire capacity of the panel on its own.

I also haven't looked up the specs on the panel, but I bet its rated well above 50 amps.

You might also be able to install tandem breakers to get more spaces, but that panel might not allow for it.

 

[Vaggeto]

I don't know the code requirements for a subpanel like that. I don't really think that it would be inappropriate to move the input wires to the power lugs and install a 30 amp breaker for the EV. It would definitely be a bad idea to use the same 50 amp breaker as an output, because then the EV could use the entire capacity of the panel on its own.

I also haven't looked up the specs on the panel, but I bet its rated well above 50 amps.

You might also be able to install tandem breakers to get more spaces, but that panel might not allow for it.

That's a really interesting idea. I'm not sure I've got the cable length to reach those power lugs but that would be the most convenient solution.
I'm not clear on the code requirements either, but I've read some areas require a local "disconnect" for the sub-panel and the easiest way to achieve this is to use a breaker instead of a disconnect outside of the unit. I think a double tap on that 30amp would achieve the same and I would just know that if I turned the lights on and charged an EV, it would trip the breaker. (Much that same that you know if you run a blow-dryer and a space-heater on plugs within the same circuit in your home it will trip the breaker)

 

[Sophias_dad]

I'm pretty sure that double tapping on that 30 amp is against the rules since one of those is an EV. It'd be different if it was a couple of plain old outlets...

On the other hand, there's one of these...for $22...

Square D Homeline 2-20 Amp Single-Pole 1-30 Amp 2-Pole Quad Tandem Circuit Breaker-HOMT2020230CP - The Home Depot

I'm not sure if that is compatible with your panel, but it could replace both of your 20 amp single breakers and give you a duplex 30 amp breaker in the same space.