240 volt 30 amp circuit installation question

[Prosdog]

Just joined this forum, got my M3 last week, black 2020 performance stealth extended range. LOVE the car.

120 volt charging was a joke, 3-5 miles per hour wasn't going to work. Had an electrician put in a 240 volt 30 amp circuit that gets me 24 miles per hour. Things are good. But, I'm a little concerned about the installation. I read up on it and I understand that electricity coming into the house is at 240. The main box provides 240 to the AC, water heater, range, and the box in the garage. The box in the garage splits that 240 into two 120 phases with half the circuits being on one phase and the other half on another. All the stuff I've seen says you put in a 30 amp breaker that fits into and pulls from 2 adjacent slots to achieve 240 from the 2 phases.

My guy tells me that my box doesn't work that way. So he put a 30 amp breaker in one slot and put another 30 amp breaker in the slot 2 below that one, not the adjacent one. Those joined together to power the 240 outlet. Well, it works so I'm guessing he's right, but does that make sense? When I sell the house am I going to be told it's not up to code? Thanks in advance.



Originally: Slot 20-20 Amp-Garage door opener

Slot 22-Empty

Slot 24-Empty

Now: Slot 20-30 Amp-Tesla Charger

Slot 22-20 Amp-Garage door opener

Slot 24-30 Amp-Tesla Charger

 

[Prosdog]

This might make it easier to visualize. Couldn't figure out how to edit my original post.



Originally:

Slot 20 20 Amp Garage door opener

Slot 22 Empty

Slot 24. Empty




Now:

Slot 20 30 Amp Tesla Charger

Slot 22. 20 Amp Garage door opener

Slot 24. 30 Amp. Tesla Charger

 

[iluvmacs]

I haven't seen this before myself, but it's plausible. In any case, if he hooked up the two poles of the 240V breaker to the same phase, you wouldn't get any power. The very fact that it works basically proves that it's correct. Can you post a picture?

 

[haggis444]

Can you send a picture of your panel? One thing that seems off to me is that when you do a 240V circuit you want the breaker switches to physical be tied together in the box. So you can shut off the entire circuit vs. just one phase of it. It's a safety thing. Something does seem off here.

 

[Prosdog]

I haven't seen this before myself, but it's plausible. In any case, if he hooked up the two poles of the 240V breaker to the same phase, you wouldn't get any power. The very fact that it works basically proves that it's correct. Can you post a picture?

Can you send a picture of your panel? One thing that seems off to me is that when you do a 240V circuit you want the breaker switches to physical be tied together in the box. So you can shut off the entire circuit vs. just one phase of it. It's a safety thing. Something does seem off here.

My thoughts exactly. If the circuits aren't adjacent and have that piece of plastic bridging them, they won't necessarily trip together. That's what worries me. That and selling the house in a few months if it isn't up to code. I'll try to post a picture later when I have access to the box. Thanks.

 

[dmurphy]

My thoughts exactly. If the circuits aren't adjacent and have that piece of plastic bridging them, they won't necessarily trip together. That's what worries me. That and selling the house in a few months if it isn't up to code. I'll try to post a picture later when I have access to the box. Thanks.

As long as the handles are tied - I’ve seen it done with a piece of ground wire - it should be OK. Odd that they’re not adjacent; not saying it’s wrong (as mentioned above, if the car is charging then it’s right) but unusual. Curious what panel it is. If you can take a photo of both the breakers as well as the sticker inside the door (with the manufacturer, model etc) that’d be super helpful. Thanks!

edit: this sounds like a split-bus panel, now that I think about it. Curious to see the layout in a photo.

 

[Raro]

Each breaker must be on a different phase, otherwise you wouldn't be getting 240V to the car (does it read 240v on the screen while charging?

like others said above, the breakers need to be tied together, with the garage opener breaker in between two charger breakers im assuming he tied all 3 together... that would be pretty shitty to be honest, if you trip the charger your garage opener wont work and vice versa...

Did he get a permit for the work? He should have, other than minor repairs or wiring that is carrying less than 50v requires it in San Antonio...

 

[Prosdog]

 

[Prosdog]

Second picture got cut-off a little. Here's a better look.

 

[zannman]

Looks like a normal 2 pole breaker would work fine if in slots 20-22 based on wiring diagram. Move whatever is currently in 22 down to 24.

I wouldn't ever advise using single pole breakers on 240V legs. Very easy for you to have one trip and still have power on part of the circuit that "doesn't work" when you're troubleshooting.

 

[Raro]

Second picture got cut-off a little. Here's a better look.View attachment 614143

20 and 22 could have been used for the charger and the bottom one could have taken the garage opener...

Was this guy the lowest bidder?

 

[dmurphy]

Looks like a normal 2 pole breaker would work fine if in slots 20-22 based on wiring diagram. Move whatever is currently in 22 down to 24.

I wouldn't ever advise using single pole breakers on 240V legs. Very easy for you to have one trip and still have power on part of the circuit that "doesn't work" when you're troubleshooting.

Ahh - except these are all half-width ("cheater") breakers it appears.

Appears I was wrong and these are actually full size breakers. They're narrow. But doesn't change the below - per the diagram, 20 & 22 would be perfect for a 2-pole breaker. (Like you said ...)

The right thing to do is swap - like you said - 22 & 24 - and then handle-tie 20 & 22 (the two poles of the 240V circuit.). Here's a handle tie for THQP breakers: GE THQP 1/2 in. Single-Pole Handle Tie-THT1 - The Home Depot

That's one full panel right there.

 

[Xambler]

Looks like the electrician had a brain freeze when he noticed that the 240 wouldn’t work in spots 22 and 24 so only moved breaker in spot 20 down one spot (or got lazy if the wiring was too tight to move it further down). What seems strange though is that all the other breakers are just 20 amp...usually expect a few 15 and definitely some 30 amp at least with a few other 240v circuits.

 

[Prosdog]

Looks like the electrician had a brain freeze when he noticed that the 240 wouldn’t work in spots 22 and 24 so only moved breaker in spot 20 down one spot (or got lazy if the wiring was too tight to move it further down). What seems strange though is that all the other breakers are just 20 amp...usually expect a few 15 and definitely some 30 amp at least with a few other 240v circuits.

Then other 240v come off the main panel at the side of the house. This I guess is considered a sub-panel.

 

[zannman]

Ahh - except these are all half-width ("cheater") breakers it appears.

Appears I was wrong and these are actually full size breakers. They're narrow. But doesn't change the below - per the diagram, 20 & 22 would be perfect for a 2-pole breaker. (Like you said ...)

The right thing to do is swap - like you said - 22 & 24 - and then handle-tie 20 & 22 (the two poles of the 240V circuit.). Here's a handle tie for THQP breakers: GE THQP 1/2 in. Single-Pole Handle Tie-THT1 - The Home Depot

That's one full panel right there.

Agreed - but the cost of a THQP230 2 pole breaker is comparable and won't raise eyebrows later. Curious why OP didn't just put in 40 or 50A capable wiring if the run is contained in the garage. You'll probably want to derate your charging pull to 27A in the car based on this setup and assuming 10AWG wiring.

Edit to say I did this with another EV for years.

 

[beachsideev]

yeah, I'm surprised you didn't run a 50a circuit. seems like a waste.

you'll have to derate it 20% not 10% so the max current you can charge at is 24a.

 

[Prosdog]

According to the electrician (friend of wife's family) he didn't want to go over 30 amps on a sub panel, would only do it from the main panel which would have required running a pretty good length of wire. We are selling the house soon so it didn't seem worth the effort. If it isn't code, I'll just yank it out before we sell.

 

[TheRFMan]

yeah, I'm surprised you didn't run a 50a circuit. seems like a waste.

Electrical service coming into the house may not have been able to accommodate 50A with A/C, dryer, range and water heater.

 

[medphys3]

That's interesting. Going from top to bottom (on either side) the breakers pull power from one leg, then the other leg. That's why 240V breakers come together as a pair. When you snap it in place, once breaker pulls from the left leg and the other from the right so you end up with two legs out of phase with each other with 120V on each leg. If you look at a picture of the inside of a panel with no breakers installed, you can see it.
Did you actually watch him connect everything? It could be (probably) just mislabeled. When you trip the one labeled "garage door opener," does it actually shut off the garage door opener?

Edit: I just re-read your original post. Maybe the box in the garage is an odd-ball. But still, killing the garage door opener should confirm.

 

[SageBrush]

I read up on it and I understand that electricity coming into the house is at 240

No one confuses me with an electrician, so take the following understanding with a grain of salt:

3 wires exit the transformer and enter the main panel: 2 hot wires and one neutral. Each hot wire is 120 volts, 180 degrees out of phase with the other wire. So if you want to power a 240 volt appliance at home you are always wiring the two 120 Volt wires that came from the transformer together.