Charging Outlet

Charging Outlet

I planed to install Nema-14-50 240v outlet in my garage. What is average cost from Sun city or local electrician for installation ? And could I just relocate and use my 240v outlet from old dryer outlet t?

sandman | 16 januari 2013

There are numerous threads on this but what I found is that going to a local trusted electrician is your best bet for pricing. Just my 2 cents...

Regarding re-using the existing wiring from a 240v dryer outlet. You need to know the present circuit's current limits, the gauge of wires used, and what else(if anything) is also using that circuit to know if you can reuse the wiring.

You should look at this type of site to see what you've already got there. I think 30A is standard for dryers and that will get you about ~25mi/hr. Might be enough.

ghillair | 16 januari 2013
jat | 16 januari 2013

The wiring for your dryer outlet is almost certainly sized for 30A intermittent, which means you could only charge at 24A. It is fine according to code (but I am not an electrician, and your local code may differ) to put a 14-50 outlet on it since the breaker will protect the wire (don't swap out the breaker without replacing the wire though!). You will trip the breaker unless you tell the car to charge at only 24A (which is easy to do and it remembers based on the location).

jbunn | 16 januari 2013

Good advice in the last couple comments. Another point is you won't actualy have a fully rated 14-50 outlet. If that suits your charging needs for your expected mileage, that's sufficient.

The question though about "how much for an outlet" is completley meaningless. It's like asking "how much is a car?" or "how far is it to Portland?" The answer is "it depends". Depends on the location from the panel, if it needs to be in conduit, if it has to pass through walls, ceilings, concrete, if the panel can accept another 50 amp breaker, if your house service can support an additional 50 amp load, if you need permits, if it's an exterior mount, where you live, etc, etc.

DJay | 16 januari 2013

Mine was installed just today. It was a 60 foot run, number 6 wire, with no conduit, and cost $589 from a local electrician. The wire run required remove of some sheet rock to gain access. Sun City quoted $1000 over the phone. Unless you are really short of cash, I would suggest you consider a new run with a 50 amp breaker as recommended. He also was able to place it on the ceiling in the middle of my two car garage, so it will be usable on either side front or rear. I plan to put a bracket on the ceiling next to the outlet so I can coil the excess cord. Now all I need is the car.

Pungoteague_Dave | 16 januari 2013

jayhicks - I am no expert, but my electrician showed me a wire sizing chart indicating that the minimum size wire for these chargers is 4, and 3 is best. Your #6 wire will overheat according to him.

jat | 16 januari 2013

@Pungoteague_Dave - he is either showing you an aluminum wire chart or trying to get you to buy more than you need. #6 copper is good for 55A (you can get more if you use insulation rated for a higher temperature).


Note that you have to derate it by 25% for running a continuous load (more than 3 hours, which is why the car will only draw 40A on a 50A receptacle/breaker), and for the ambient temperature. Note that 60 degC insulation on #6 is only good for 50A at up to 35 degC ambient temperature (95 degF), so if you expect hotter temperatures where this is installed you will need to either use 75 degC-rated insulation or go to #4 copper.

ChasF | 16 januari 2013

There are numerous charts out there that show differing wire sizes for 50 amp runs. I've seen some that say #6 wire is acceptable for runs of about 25ft and Home Depot seems to agree. Another rule of thumb to follow is that less than 2% drop in voltage is acceptable. Knowing that #6 wire has resisitance spec'd at 250 milliohms per 1000 ft, and some simple math: (Voltage Drop = I x R = 50 x 250 x(N ft/1000 ft), where N is the length of your run. As long as this calculates out to less than 2% of 240V, he should be fine.

jat | 16 januari 2013

@ChasF - E=IR has resistance in ohms, not milliohms, so shouldn't that be .25 in your formula?

But generally, you have to choose a wire size that satisfies all the constraints. One is how hot it will get for a given current, and how hot the insulation on it can withstand before it will melt. The voltage drop is a separate criteria -- you might have wire/insulation that can handle the current, but it is too long for the voltage drop required so you have to get heavier wire. Likewise for the reverse.

There are a lot of factors, and if you don't know what you are doing you should hire an electrician (though it doesn't hurt to be informed so you don't get taken).

ChasF | 16 januari 2013


Good catch. You're right, it should have read .25 ohms in the context of that formula.

All good, valid points. | 16 januari 2013

My Solar City install cost $450.00. This was within 5 feet of the electrical panel & did not require a subpanel. They did an energy audit of the entire house as part of the install. All work was permit & inspected. I am in Colorado.

warthog97 | 16 januari 2013

I had a NEMA 14-50 installed in my garage. The run was only a couple of feet from my panel, and the electricians were already at the house installing a 3kW solar array at my house. Total price was around $100 for the outlet.

shop | 16 januari 2013

I wouldn't use a dryer outlet, it isn't going to have the current you want. Just spend the money and do it right. All you need is panel space, as the electrical load will be at night when few other big loads (like almost none) are going to running. Even if you have to add a subpanel, it would be worth it.

jat | 16 januari 2013

@shop - personally, if you aren't going with the HPWC you are planning on charging it overnight anyway. In that case, 24A is plenty to recharge it from 0-85kWh in about 14 hours, and practically anything like a typical day's usage will easily fit in the time you have overnight. So, if the 10-30/14-30 adapters were available, you weren't getting the HPWC, and you didn't need the dryer outlet or were happy sharing it, then there would be no reason not to just use that rather than run a new 14-50 outlet. However, you can't get the dryer outlet adapters yet (I have tried, as I will need it when I travel to friends/family out of town).