electrical code question

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

RustyShackleford

Minister of Fire
Hearth Supporter
Jan 6, 2009
1,352
NC
I'm installing an EVSE (charging station for an electric car) off an existing subpanel. It's a 20-amp EVSE, so I'll use 10awg THWN in PVC conduit and protect with a 25-amp breaker. (Yes, I know I could run a 30amp EVSE, but the subpanel doesn't have that much unused capacity - separate discussion). The EVSE requires no neutral, so I'm just running green/black/red.

There's a place along the way where I'll put a conduit body, to ease pulling the wire. It's not real far from the subpanel, and it turns out it's also a place where it'd be really nice to have a 120vac convenience outlet. So I'm tempted to run a neutral to there (along with the ground and 2 hots for the EVSE) and put an outlet there. Then continue on to the EVSE, without the neutral.

Is this legit or code-compliant ? I'm using 10awg THWN protected with 25-amp OCPD, so that's all good. But that 25-amp breaker is also protecting a 15- or 20-amp outlet (I guess I should use a 20-amp one). So I wonder if that's ok ?
 
I'm not an electrician and it's been a year since I read the code book. I'd be happy to be proven wrong.

The EVSE needs a dedicated circuit.

The options I can think of are:
To run an additional circuit and wire to the outlet if there is room at the sub panel, which it sounds like there isn't.
Set an additional sub panel at the outlet location and then separate the outlet and the EVSE with two separate circuits.
Set an additional sub panel at the EVSE location and then run a circuit and wire back to the outlet.

Electrically, there is no reason why you can't do what you are wanting. It has been done "a few times" in the past and still currently done.
 
The EVSE needs a dedicated circuit.
...
Electrically, there is no reason why you can't do what you are wanting. It has been done "a few times" in the past and still currently done.
Nice summary.

To run an additional circuit and wire to the outlet if there is room at the sub panel, which it sounds like there isn't.
Actually I believe this is the perfect solution ! There's already conduit (for the EVSE) running from the subpanel to the place where I want the outlet - and it's not very far. And there's another one-pole breaker available in the subpanel. I can use the EGC for the EVSE there; so just add a white and a black strand of 12awg !
 
  • Like
Reactions: EbS-P
Looking at the "Electrical Horror Show" post it sounds like you know what you are doing.
Well, I haven't burnt that house down yet, anyhow.
 
Just for completeness outdoor outlets need to be gfci. I’m not going to even mention how they wired a120V outlet at my 240V irrigation pump using 12-2.
Glad you are doing it right. That’s why you chose bigger conduit.
 
how many open slots left in your panel? I know in this area you have to have a few remaining open slots in your panel if not you have to upgrade the panel.

Probably not something you are looking at but have you looked at a plug panel that RV parks use? Basically what you are wanting to do but they have a breaker in them so you can shut down one feed while the other is in use.. I built a few when i worked at a park but i left out the breakers.
 
how many open slots left in your panel? I know in this area you have to have a few remaining open slots in your panel if not you have to upgrade the panel.

Probably not something you are looking at but have you looked at a plug panel that RV parks use? Basically what you are wanting to do but they have a breaker in them so you can shut down one feed while the other is in use.. I built a few when i worked at a park but i left out the breakers.
Depending on the panel you can get tandem 240v breakers. For example

Your friend has shared a link to a Home Depot product they think you would be interested in seeing.



 
Well, the subpanel is already installed and I'm not changing anything for this, it's just a convenience outlet. But since you asked, it's a Siemens panel with four spaces (1") and eight circuits (meaning you can fully-populate it with space-saver breakers. There's one two-space space-saver, which has a double-pole for the minisplit I put in, a single pole for a convenience outlet by the compressor, and an unused single-pole. So there's two empty spaces. I'll fill that with a 25-amp double-pole for the EVSE.

This new convenience outlet would be inside. I'm putting the conduit-body at a place where (in the future) I might want to come into the basement and run heavy wiring from the main panel. So there's be a stub from the conduit body (a 'T' type) coming into a metal box on the inside. There's where I might run heavier wiring and where I'd put the outlet. I can't do that till I open up room in the main panel (by disconnecting the baseboard heat in the MBR), and putting in another minisplit for it (which would come off the subpanel). Make sense ? The fabulous thing about this Emporia EVSE I'm installing is that you can set the charge current anywhere from 6 amps to 48 amps ! And at $399 it's cheaper than most.
 
  • Like
Reactions: EbS-P
Years ago when I renovated my basement, I consolidated a few low-use circuits and ran power to a new sub-panel. The main 100amp panel and the subpanel are both fully utilized. Next step someday is to bump up to the 1980s, and get a 200amp panel!
 
hey rusty how many amps is the sub panel? each new circuit should be arc fault and if so it will keep blowing the breaker. if the car charger is a plug type then you will have to gfi it. if it is straight wired to the charger and no plug then you don't need a gfi breaker. those breakers are about $110 to 120 dollars alone. if you plan on putting another mini split on that panel you wil be pushing it with all three running. also what size is the pipe that feeds the sub panel?
 
hey rusty how many amps is the sub panel? each new circuit should be arc fault and if so it will keep blowing the breaker. if the car charger is a plug type then you will have to gfi it. if it is straight wired to the charger and no plug then you don't need a gfi breaker. those breakers are about $110 to 120 dollars alone. if you plan on putting another mini split on that panel you wil be pushing it with all three running. also what size is the pipe that feeds the sub panel?
Subpanel is 40 amps: protected by 40amp breaker in main panel and wired with 8-3 NM-B.

I plan to hardwire the EVSE (with 10awg THWN).

The add'l minisplit is an either/or thing. If I decide to add it, I'll remove the EVSE connection to the subpanel to make room for it. And then disconnect the electric baseboard heater in the MBR and connect the EVSE directly to the main panel (30amp breaker). I'm running the conduit in such a way as to make this change easy. And the beauty of this Emporia EVSE that I bought (besides being cheaper than most at $399) is that you can set the charging current to almost anything from 6 to 48 amps; so I'd up it from 20 to 24 amps if I make that change. (I've been round and round with knowledgeable folks at stackexchange, concluding that 20 amps is the most continuous load that I can add to the subpanel (along with the original minisplit).