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Circuit Breaker capacity

Like many new people in the forum, I’ve been researching the Model 3 for feasibility. Based on what I’ve read and my requirements I think I’d fall into the NEMA 14-50 category. My house is 12 years old, two car garage, circuit breaker placed on the right wall.(standard stuff) I took a picture of my box and it would appear there isn’t a single open slot. When things progress further I’ll certainly reach out to an electrician but for now I’d appreciate feedback and options. What would take to add connection?

Thanks in advance.


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Well-Known Member
Supporting Member
Jan 12, 2011
San Luis Obispo, CA
You can make a spot by getting twin 15's and twin 20's and remove the two single 15 amp breakers and the two 20 amp breakers. An electrician will tell you if you have the load capacity. Take care to maintain the GFI capability of the 15 amp bathroom breaker.


Active Member
Mar 4, 2013
Redmond, WA
It looks like your circuit break support tandem-circuit breakers on every slot. (You already have 7 of them scattered all over the place).

So if you :
a) tandem up #2, #4 with a 15amp to become the new #2,
b) move your current #6 (tandem) to #4
c) tandem up #8 and #10 with a 20amp and move it to #6

You'll have a double slot open over #8 and #10 in which you can install a NEMA 14-50 breaker.


Knows where his towel is
Apr 23, 2015
You most likely need a new box with a higher amp. You may need to check your city electric code, but I highly doubt you can merge some of the lines into one switch. You have seems to have a 100 amps breaker so you probably need to upgrade to a 150 amps
The breaker on the very bottom you mean? It's not a 200? Or am I looking at the wrong spot? Just trying to learn something new.


Active Member
Mar 4, 2013
Redmond, WA
200 amp should be plenty for that panel, even after adding the Tesla. Check with an electrician of course.

However, I just noticed - bornnacadillac has both a 'range' and a 'gas range'.

Did you (or a previous owner) by any chance take out an Electrical Range and replace it with a Gas Range? If so, then you already have #7 and #9 free, and you can just replace that breaker with the breaker for the EVSE.


Active Member
Mar 4, 2013
Redmond, WA
If all else fails, theoretically could the OP have a bigger breaker box (or whatever you call it) put in?

Absolutely, but that's a $1000 line item rather than a $100 one.

He shouldn't need to though - he has tandem spaces available in that breaker box.

Now if the issue is that he needs a > 200A feed, then it becomes an entirely different story that doesn't end well.
Another option, and the one my electrician chose for me, is a second breaker box like this one. What you would do is pull that 30 amp dryer pair down in the lower right of your panel, replace it with a 90 amp breaker, and that 90 would feed the secondary panel. It's a 100 amp secondary panel, so the 90 would be fine. Then you put the pair of 30's for your dryer back in the 90 amp add-in panel. Two of six new slots down. And of course, you extend the wiring for your dryer to the breaker's new location. Then you take the next two of the six slots and you put a 50 amp breaker pair in there, which you will use to power your NEMA 14-50. You even have room to power your second Model 3. :rolleyes:

But then, if you don't have room for a secondary panel, you need to get creative per some of the suggestions above.
Maybe put all LED bulbs in all bedroom lighting and then combine the circuits feeding 4 bedroom lighting breakers into one breaker. A single 15 amp 125v breaker is rated at 1875w, so to stay at/below 80% would be 1500w of lighting. Shouldn't be too hard using LED's or even CFL's. That would leave the room you need. BTW, I'm not an electrician, so I don't know that this is actually a realistic proposal.

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