NEMA 14-50 Plug at Home

Welcome to the forum Robert. You might want to start by reading the FAQ on home charging. Lots of good information in there.
FAQ: Home Tesla charging infrastructure QA

Good question.

Screw the permit. Just do it. There are plenty of good electricians that could do it for you. Not sure why you need a transfer switch. How about adding a small sub panel and moving some circuits to that? Should not be too expensive. Even though you are only 10 min from a SC, having the convenience of plugging in at home is priceless. You don't have to stand around waiting for the car to charge up. I have a subpanel in my garage and installing the circuit (I had room) was only $300. So yours would be more. Worth every penny IMO.

Many panels support half sized breakers I used them when I added solar. I added my own NEMA 14-50 for about $70 and a morning of work.

I have a place 10 minutes away from the Petaluma supercharger and i just installed a 14-50 outlet. 2 hours of labor and parts which cost me $300. Any good electrician can do the work.

Robert's issue might be what I had to work around also, my toe home only has a 100 Amp breaker on the main. Adding the 14-50 would have put a 105 Amp peak draw, thus popping the breaker, and just as importantly not allowing any margin.

i had a transfer box installed in the garage that will only allow either the air conditioner or the NEMA 14-50 to be active at any point in time.

bahusky said:

I haven't looked into the subpanel solution. Thanks for the suggestion. Is there any photo of such installation? If the total power coming into the home is about 100A and there is no more room on the current panel, how will a subpanel help solve the problem?

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You move one 240V circuit (or use half-height breakers) to make room for a breaker that will then feed another breaker panel.

There are 2 capacities you have to worry about - the first is room in the panels for the breakers -- if your panel is full, you will need a subpanel added (on some panel types you can substitute half-size breakers for full-size and gain some spaces back as well). The second capacity is your load calculation, which is why your electrician is telling you that you would need to have an "either-or" transfer switch to prevent overloading your service. There is a specific calculation that is used (NEC article 220), and there are plenty of online resources to help you there.

Most places in the US will require an electrical permit to add or extend a new circuit. Some will require an inspection. In the SF bay area, permits and inspections are required by law nearly everywhere. Adding a 14-50 is relatively simple and straightforward, and it's your choice as to whether to follow the law or not (typical building code law generally states that it's considered a separate violation for each day that a modification goes unpermitted & uninspected). It's unlikely you would get caught, unless your addition caused an accident/fire/loss and the fire and/or insurance inspectors started to dig into whether permits were issued for it - I've seen that happen, but extremely rare.

Electrical wiring is not hard to do, but takes some knowledge of how to do it properly. If you're comfortable with learning a new trade, you should read a few of the basic wiring books that are available - and use my FAQ (see my signature). If you're still concerned that things are a bit over your head, call an electrician -- the Tesla is the largest appliance (in terms of kWh drawn) that most homeowners will ever see, and you want its supply to be safe.

My service is only 100 amps at my location and the electrician was able to add a breaker on that panel so I didn't need a sub panel. I had the plug installed in the garage on the other side of the service panel wall. If you aren't an electrician hire one. It isn't worth getting hurt.

bahusky said:

Thanks for the info. I think that's exactly what I need. One electrician told me that's the option to go for it. The quotes I am getting from electricians are all over the place. Some as high as $2500 to install this thing with permit. That's simply insane amount just to put in a plug. Did you install this yourself or did you hire some electrician to do this? Did they charge a lot for this if you don't mind me asking.

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I agree with you to avoid the wait at the super charger. I noticed it is always packed each time I am there and I was usually the last lucky one to get a spot before some other Telsa owner showed up 5 mins after me.

It would definitely nice to be able to install it since my panel is right in the garage and the plug I want would be maybe 5 to 10 feet away from the panel. Do you have instruction on how you installed it? I am pretty handy but I also don't want to get electrocuted. Is there a good guide you followed to do the work yourself? Thanks for your help.

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I haven't looked into the subpanel solution. Thanks for the suggestion. Is there any photo of such installation? If the total power coming into the home is about 100A and there is no more room on the current panel, how will a subpanel help solve the problem?

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I also installed the power transfer switch between the 50A circuit to the house HVAC and the HPWC.
It works well and I have never had any overlap with my evening charging scheduled to start at 9 PM.

FlatSix911 said:

I also did the power transfer switch between the 50A circuit to the house HVAC and the HPWC.
It works well and I have never had any overlap with evening charging scheduled to start at 9 PM.

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Don't you just love California?

FlasherZ said:

Don't you just love California?

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Ha, I know what you mean regarding the tiered utility rates ... $0.13 - $0.45/ kWh!
Fortunately,I also have Solar panels so the Time of Use rates save me after peak hours.

FlatSix911 said:

Ha, I know what you mean regarding the tiered utility rates ... $0.13 - $0.45/ kWh!
Fortunately,I also have Solar panels so the Time of Use rates save me after peak hours.

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Well, I was more referring to never having A/C overlap with charging. When I lived in the bay area, I was happy just to open the front and rear doors and let that cool air rush through the house. Here, it doesn't quite work that way - A/C needs to run 24 hours a day when the overnight low doesn't even drop below 80 degrees during humid summers.

The good news? From a power perspective, we get volume discounts - my rate is lower when I go over 2,000 kWh/month.

That panel is pretty full. You can't turn the A/C breaker into a half-breaker because 240V breakers must consume two spots, but there may be one option. Your electrician will have to look up the specific panel and its ratings to determine whether that is possible. There is a way to squeak out a few more breakers

Provided the panel allows for it, you could replace that 40A double-pole in spots 10-12 with a Square D HOMT2020240, which is a 40A 240V breaker with two 20A 120V circuits on the outside. You would then move the circuits from spot 8 to those outside circuits. Then, you'd install a HOMT2020250 in spots 6-8; the 120V circuits currently in spot 6 would go to the outside, and your NEMA 14-50 would then connect to the 240V/50A breaker in the middle.

(EDIT: I modified the above because I found that SqD makes a 2020240, when I looked last night I didn't see it. Pairing up with the double-pole in 10-12 is easier than 18-20 because of wire length when moving circuits in the box.)

That would be the only way you could do this - if your panel allows it - without putting in a new subpanel.

My panel is full as well. When I had an outside electrical issue I asked the electrician about putting in a larger panel, but unfortunately since I have an old house, my outside service would actually have to be upgraded when my panel is upgraded to let more power in. Might want to be sure your service can handle more load or if you need other work done to add that.

All of that work is priority #1 before I get my first Tesla.

McHoffa said:

My panel is full as well. When I had an outside electrical issue I asked the electrician about putting in a larger panel, but unfortunately since I have an old house, my outside service would actually have to be upgraded when my panel is upgraded to let more power in. Might want to be sure your service can handle more load or if you need other work done to add that.

All of that work is priority #1 before I get my first Tesla.

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My installation included addition of sub-panel (now have extra capacity for future needs), relocation of circuits, and about 25' of conduit over and around a garage door to the NEMA 14-50 on the wall between two doors. $800 by Nick Athan of Apex, the Tesla recommended electrician. About a 4-5 hour job. Recommended.

bahusky said:

Hi,

Sorry if this question already been asked before. I just got a Tesla and want to install a NEMA 14-50 plug in my garage. The electric panel is there already and it is full. I have an AC unit thats using 40A and we don't use it at all. One electrician told me I need to install a transfer switch for this and the Tesla charging port.

I am in the SF Bay Area Redwood City area. My questions are:

1. Can I just hire an electrician and install this plug?
2. Do I have to get a city permit? Obviously, cost to get a permit would be very expensive.
3. Anyone that live in the Bay Area care to share their story?

Please note nearest Super charger to my house is about 10 mins drive. I am not sure it is worth it to spend up to $2K just to install a port in my garage.

Thank you in advance for your help.

Robert

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While the process of adding one isn't too difficult, I would recommend hire a license electrician and get permit to install. Permit from the city itself it fairly inexpensive. If you have our electrician pull the permit for you, that is where the cost it is. You can save that cost by going out and pull the permit yourself. Just ask your electrician for the info you need to fill out the form.

Why? If there were to be a fire to your house and your insurance company comes out to inspect. Turned out it is your NEMA 10-50 didn't have a permit, you could potentially not have your house covered. That is a high risk for what if....I would rather not deal with that.

It add, the electrician first look at your panel to see if you have the room If it has room, they add a 50AMP breaker...pull the line through the garage and connect it to the 14-50.