Sharing a 40 amp circuit with Oven?

[Kuro Houou]

So when I had my house built I told them I wanted a 240v outlet in my garage, this was 9 years ago, before I even knew of Tesla's really let alone that much about EV's. All I knew was EV's would probably come one day, maybe I should have a larger outlet available just in case. So Turns out my builder put the outlet in the garage like I asked, but it looks like it was just run as a split between my oven and this outlet in the garage (It's actually just capped, not outlet yet). So in my circuit breaker panel, its labeled as Wall Oven and is a single 40amp breaker. I have a dual oven as well just a fyi.. So my question is, is this even usable... I feel like the builder just took the short cut and of course didn't run a separate wire/breaker for the garage 240v outlet. Is there anything I can do in this case? Maybe use a smaller outlet like a NEMA 14-30 or 10-30 (not sure exactly what the difference is there). My breaker panel only has two 1/2 (single) slots left, so very little room for expansion

 

[Cipe]

You can still use that circuit to charge. Just set your car to charge in the middle of the night or any other time when you won’t be using the oven.

Edit: or just use the app to stop your car from charging anytime you fire up the oven. It doesn’t seem like it would be a big inconvenience.

 

[Big Earl]

Have you opened the circuit breaker panel? It’s possible (expected, actually) that your electrician ran the wires to the panel but never added the circuit breakers.

 

[pdp1]

So when I had my house built I told them I wanted a 240v outlet in my garage, this was 9 years ago, before I even knew of Tesla's really let alone that much about EV's. All I knew was EV's would probably come one day, maybe I should have a larger outlet available just in case. So Turns out my builder put the outlet in the garage like I asked, but it looks like it was just run as a split between my oven and this outlet in the garage (It's actually just capped, not outlet yet). So in my circuit breaker panel, its labeled as Wall Oven and is a single 40amp breaker. I have a dual oven as well just a fyi.. So my question is, is this even usable... I feel like the builder just took the short cut and of course didn't run a separate wire/breaker for the garage 240v outlet. Is there anything I can do in this case? Maybe use a smaller outlet like a NEMA 14-30 or 10-30 (not sure exactly what the difference is there). My breaker panel only has two 1/2 (single) slots left, so very little room for expansion

Code requires large electric appliances to be on a dedicated circuit, meaning you cannot share multiple outlets in it. So it will be violating code if you add another outlet.

That said, physics is physics, and if the total draw on the circuit at any given time is less than 40amps, it will work... just know you could be risking fire and insurance won’t cover it.

 

[jjrandorin]

To answer your original question, OP, no, you can not "share" the connection with your wall oven. EV charging must be a dedicated circuit, and so do wall ovens.

you might want to check to see if its actually shared, or as mentioned, the wiring is there for an individual run but no breaker. It might be something as simple as you (or having someone) add the breaker. If its actually a shared circuit, I dont think the wall oven would be to code (but there are people who are much more knowledgable than me, which isnt hard at all, on this topic who hopefully will confirm).

 

[Kuro Houou]

Have you opened the circuit breaker panel? It’s possible (expected, actually) that your electrician ran the wires to the panel but never added the circuit breakers.

I have not opened it up to look behind it.. just seems to convenient that the builder put the outlet in the garage on the same wall as the oven, opposite sides obviously... But that is curious about the code comments.. I am sure the builder knows the codes and wouldn't put a major appliance like a oven on the same circuit as an outlet in a garage then.. looks like I have to do some more digging on my end.

 

[Big Earl]

I have not opened it up to look behind it.. just seems to convenient that the builder put the outlet in the garage on the same wall as the oven, opposite sides obviously... But that is curious about the code comments.. I am sure the builder knows the codes and wouldn't put a major appliance like a oven on the same circuit as an outlet in a garage then.. looks like I have to do some more digging on my end.

Sure. It’s convenient to pull two sets of wires to the same location at the same time. Why wouldn’t they do it like that? Not really a good indication that they’re shared.

 

[Kuro Houou]

I totally forgot I took pictures of my house pre-dryall inspection, so all wiring had to be done Big Earl you were right, two separate runs.. just no breaker installed in the breaker panel. So looks like depending on the wiring, I could install probably at least a 40amp breaker, maybe a 50amp.. have to check the guage of the wire.. while not the perfect situation (would have been nice if they already had put the breaker in) at least this way I don't have to do extra wiring which really would have been the most expensive/hardest part.

 

[mswlogo]

If the outlet was capped off, it might be unconnected in the breaker box as well with no breaker for it. Open up the panel and I bet there is a line there capped off. All they did was run a wire and assuming it has something to do with the oven circuit. If you just said 240V and no amps it could be as small as a 20amp 12-2. Be nice if it was 30 amp 10-2 or larger.

 

[Kuro Houou]

Darn, looks like they only installed 12 gauge wire Well looks like I am running a whole new wire.. not a huge deal, probably better anyways as I wanted the charger on the front of the garage not the back since Tesla's charge ports are in the rear of the car.

 

[Xenoilphobe]

If you have to run a new wire, you drop in 100 to 200 amp sub panel, so you know for the next Tesla, or Zero or whatever... that's what I did and we are about to get our third Tesla.

 

[Kuro Houou]

If you have to run a new wire, you drop in 100 to 200 amp sub panel, so you know for the next Tesla, or Zero or whatever... that's what I did and we are about to get our third Tesla.

Yeah! Now that I know the amount of power I need that makes sense! I have a 200 amp panel for the house now, so almost makes sense to install a second. It does bring up an interesting question about electric cars.. Growing up my family had 4 cars at one point (there were 4 kids including me and my parents) as we all started driving, obviously we all started getting our own cars. I don't even know how we would have handled that if they were all electric! Would have had to have some kind of chargers in the front driveway lol.

 

[Xenoilphobe]

Believe me, my son has it already figured out, he's in charge of the rotation schedule - keeps begging for my old Model S, which should have about 160K miles by the time the CyberTrucks show up.

 

[Kuro Houou]

Believe me, my son has it already figured out, he's in charge of the rotation schedule - keeps begging for my old Model S, which should have about 160K miles by the time the CyberTrucks show up.

Lol, good point, put them in charge of rotating the cars through the chargers

 

[mswlogo]

Darn, looks like they only installed 12 gauge wire Well looks like I am running a whole new wire.. not a huge deal, probably better anyways as I wanted the charger on the front of the garage not the back since Tesla's charge ports are in the rear of the car.

For the record 20A 240V is 15mph (~150 miles overnight). My X is on a 30A (because that’s what I also so happen to have in my garage ahead of EV). Which charges at the same rate. And it’s absolutely fine. Even in cold climate. Sure, if I were doing a new install I’d do 60amp for ever so slight improvement in convenience. But not worth the trouble. And my walls in the garage were still open and I didn’t bother to upgrade the line.

EV cars should use LESS electricity over time, not more. I also charge a Volt on 20A 120V in the same garage.

 

[Xenoilphobe]

Lol, good point, put them in charge of rotating the cars through the chargers

Hopefully by then, they can automate the summon system just to move the cars once charging completes.

 

[Xenoilphobe]

For the record 20A 240V is 15mph (~150 miles overnight). My X is on a 30A (because that’s what I also so happen to have in my garage ahead of EV). Which charges at the same rate. And it’s absolutely fine. Even in cold climate. Sure, if I were doing a new install I’d do 60amp for ever so slight improvement in convenience. But not worth the trouble. And my walls in the garage were still open and I didn’t bother to upgrade the line.

EV cars should use LESS electricity over time, not more.

Model 3 ~ 220 watts per mile
Model Y ~ 250 watts per mile
Model S ~ 280 watts per mile
Model X ~ 300 watts per mile
Roadster ~ ????
CyberTruck ~ ???? ~ 400 watts per mile
Semi ~ 1000 watts per mile
Future RV Camper ..

I'm not sure that's actually true as they add diversity of platforms to the Tesla Fleet, but your point is valid.

 

[Kuro Houou]

For the record 20A 240V is 15mph (~150 miles overnight). My X is on a 30A (because that’s what I also so happen to have in my garage ahead of EV). Which charges at the same rate. And it’s absolutely fine. Even in cold climate. Sure, if I were doing a new install I’d do 60amp for ever so slight improvement in convenience. But not worth the trouble. And my walls in the garage were still open and I didn’t bother to upgrade the line.

EV cars should use LESS electricity over time, not more.

Out of curiosity, what would be the type of outlet to install for 20A 240V? Is it the NEMA 6-20? I could easily install a 20A breaker and attach it to the wire in my existing box temporarily, and if needed in the future do a sub pannel.

While I do think cars should use less in the future, I am not anticipating it anytime in the near future unfortunately Seems like they are only going up in battery pack size not down.

 

[Big Earl]

Model 3 ~ 220 watts per mile
Model Y ~ 250 watts per mile
Model S ~ 280 watts per mile
Model X ~ 300 watts per mile
Roadster ~ ????
CyberTruck ~ ???? ~ 400 watts per mile
Semi ~ 1kW per mile
Future RV Camper ..

I'm not sure that's actually true as they add diversity of platforms to the Tesla Fleet, but your point is valid.

Watthours and kiloWatthours.

 

[Xenoilphobe]

Watthours and kiloWatthours.

fixed it.