Home Electrical for Dummies

[Frank99]

An outlet for charging an EV requires (most of the time) a GFCI protected outlet - generally this is done with a GFCI circuit breaker. That'll cost you $100-$150 at Home Depot.
A cheap Levition 14-50 outlet is about $10 ($20 with cover plate/box) at Home Depot. The Tesla recommended industrial-quality Hubbell 9450A or Cooper 5754N is $150 (with cover plate and box). The Bryant 9450R has been recommended as being equivalent to the Hubbell, at half the price. Question your electrician about which outlet they're planning on installing.
AWG 6 wire is about $4 / foot for the 4 wires you'll need. AWG 4 (which is good for 70 amps) will be about $8 / foot, and isn't a bad idea for future-proofing especially for such a short run. You'll also need conduit and fittings.

That's a long-winded way of saying that installing a 14-50 outlet is going to cost:
$150 - GFCI Breaker
$ 80 - High-quality outlet (Bryant), box, and cover
$ 60 - Wire to go 10 feet with usable service loops ($120 if you use AWG 4)
$ 15 - conduit and fittings
----
$300 for the hardware.

The electrician SHOULD pull a permit and get an inspection. I have no idea how much that'll cost. Let's guess $100.

It'll probably take a couple of hours to do the installation. Call it $150-$250 for labor.

So, something on the order of $600 seems like a minimum cost for a high-quality, permitted installation. Perhaps $100-$200 cheaper if the electrician was planning on using a cheap outlet and works fast.

How can you reduce costs?
- You could tell the electrician that you want the 14-50 outlet for a welder. That means you may not need a GFCI breaker; a normal breaker is $15. Some towns may not require the GFCI outlet for EV charging, if you live in one of those this is a no-brainer.
- You could use a cheap outlet, like the $10 Leviton at Home Depot. If you use a cheap outlet, make sure the electrician uses a torque wrench to tighten the screws holding the wires to the outlet; if he just uses a screwdriver, you run the risk of overheating and melting the outlet (or starting a fire).
- You could find an electrician who will do the job without a permit/inspection. ummm...yeah...not a good idea. Someone who's willing to do this is likely willing to cut other corners that you really don't want cut.

 

[Rocky_H]

Some towns may not require the GFCI outlet for EV charging, if you live in one of those this is a no-brainer.

That doesn't have to do with the town. NEC versions are adopted on a state level. OP's location says Kentucky, and Kentucky has adopted the 2017 NEC version, so the GFCI breaker is required for an outlet for car charging.

 

[Gauss Guzzler]

That's a long-winded way of saying that installing a 14-50 outlet is going to cost:

14-50 or 6-50 receptacles can accept AWG 4 wiring but it's not easy (especially with copper) and is gross overkill for 32A. In fact, you don't even need AWG 6, you can use AWG 8 with a 40A breaker and 40A label on the outlet which may considerably reduce the cost and generally provides the exact same charge performance. Bigger wire isn't necessarily better - it requires a bit more skill to safely bend and smash those wires into a box and most installation issues can be traced back to a lack of skill.

There can be a pretty significant cost difference between a 2-conductor (6-50R) run of AWG 8 vs. 3-conductors (14-50R) of AWG 6 (or AWG 4!) and either extreme provides exactly the same charge performance with the UMC. I'd even argue that "future-proofing" efforts would be better spent running two pairs of AWG 8 for multi-car charging rather than 1 trio of AWG 4 for upgradeable charging - for the same price.

 

[Jeremy3292]

14-50 or 6-50 receptacles can accept AWG 4 wiring but it's not easy (especially with copper) and is gross overkill for 32A. In fact, you don't even need AWG 6, you can use AWG 8 with a 40A breaker and 40A label on the outlet which may considerably reduce the cost and generally provides the exact same charge performance.

I'm pretty certain this is not up to code no matter what state you live in. If you install a 14-50 or 6-50 outlet it MUST be on a 50 amp breaker and then AWG 6 wire is required.

 

[Gauss Guzzler]

No, there's actually an exception that lets you put a 50A outlet on a 40A circuit as long as you write "40A" on the outlet. This may be part of the reason Tesla downgraded the UMC capacity from 40A to 32A.

You'll see that the receptacles are always rated for #8 to #4 wire as well. Generally intended to support 40A with #8 or aluminum with #4.

 

[Jeremy3292]

No, there's actually an exception that lets you put a 50A outlet on a 40A circuit as long as you write "40A" on the outlet. This may be part of the reason Tesla downgraded the UMC capacity from 40A to 32A.

You'll see that the receptacles are always rated for #8 to #4 wire as well. Generally intended to support 40A with #8 or aluminum with #4.

Ok I see what you're saying as there are no 40 amp NEMA outlets. However, Tesla says to put a 6-50 and 14-50 on a 50 amp breaker and use 6 gauge wire. Installation guides below:

Mobile Connector | Tesla Support

Mobile Connector is useful when you’re away from home and on extended trips. View the charging speed based on your model and adapter.

www.tesla.com

 

[dmurphy]

14-50 or 6-50 receptacles can accept AWG 4 wiring but it's not easy (especially with copper) and is gross overkill for 32A.

My disagreement with this is on exceptionally long runs (I mean, over 200 foot long runs.)

Likely not common in residential settings, but in MDUs? Probably more common than they should be.

 

[Gauss Guzzler]

Yes of course, #6 on a 50A breaker is ideal. But #8 on 40A or #4 on 50A are also legal, safe, and functionally identical for Gen2 UMC purposes.

I ran #6 myself, in part because the previous owner left a pile of it in the attic, but also because I'm a nerd. There's really no immediate benefit to it other than the knowledge that my electrons are a little more comfortable in there.
It's important to know that #8 is legal and adequate so that you can save some money if desired, or so that you can be sure to verify that an electrician quoted/installed the circuit size you were expecting.

 

[Rocky_H]

No, there's actually an exception that lets you put a 50A outlet on a 40A circuit

Yes.

as long as you write "40A" on the outlet.

No, that condition isn't required. You just see that recommended often here, so that people in the future will have a better idea of what is behind that outlet--it's a good idea.

This may be part of the reason Tesla downgraded the UMC capacity from 40A to 32A.

The very fact that they didn't have to be labeled contributed some to that issue I think. There are a lot of these on 40A circuits without indication, and people were plugging into them not knowing that they were overdrawing things, so yes, I think Tesla was toning it down to 32A to kind of protect/prevent from this situation of people accidentally causing this problem by plugging into things that weren't set up how they were expecting.

 

[Frank99]

My suggestion for AWG 4 was because:
1. It’s a very short run - 10 feet. The cost of wire, no matter what size, Is insignificant in this installation.
2. Today’s EVs top out at 48A home charging. That doesn’t mean tomorrow’s EV (or yesterday’s 80A Model S) won’t be capable of something greater, and putting in AWG 4 allows an easy upgrade in the future to a higher amperage charger for a future EV. It’s certainly NOT a required upgrade.

 

[Rocky_H]

Today’s EVs top out at 48A home charging. That doesn’t mean tomorrow’s EV (or yesterday’s 80A Model S) won’t be capable of something greater, and putting in AWG 4 allows an easy upgrade in the future to a higher amperage charger for a future EV. It’s certainly NOT a required upgrade.

I will caution about the fallacy nature of this regarding both charging speed and range of the "future EV".

People say stuff like this about how future EVs could charge faster, so your home charging circuits need to get bigger and bigger and BIGGER AND BIIIIIGGGGERRRRR!
Why?
As future EVs come along, the distance you drive to work doesn't also grow exponentially to 2X, 4X, 8X, etc. as much distance. You drive how far you drive. You need to refill overnight however many miles you drive--not 5 or 10 times that because future cars have more capability.

 

[Frank99]

I agree with you from a practical point of view - my home charge rate only needs to be able to charge my car in 12 hours (equivalent to "overnight). Even for a 100 kwh Model S, the 32A Gen-2 Mobile Connector will do that. I don't really see CARS going much above 100 kwh batteries, because of volume, weight, and cost limitations (well, except perhaps for some niche performance luxury cars). Even a 150 kwh battery can be charged in 12 hours with an HPWC on a 60A circuit.

But, EVs are going to be more than just cars. CyberTruck, Rivian, F-150 Lightning are just the beginning shots in the EV pickup wars. Every year, pickups get larger because the "appearance" pickup customer base (as opposed to the "working" pickup customer base) couldn't possibly be seen in a pickup smaller than the guy next to him at the light. And just like physical size and engine power have steadily increased, battery capacity will also. How big of a battery does an F-250 equivalent need to tow a horse trailer, a large boat, or a humongous 5-th wheeler 500 miles in the winter? That's how big EV batteries are going to get, because pickups don't have nearly the limitations on space, weight, and cost as most cars. And those batteries are going to need to get charged, and people are going to want to use the worst-case scenario - "Let's say I get back late with the battery at 0%, plug in at midnight, and need to hook up the trailer and drive 500 miles starting at 6:00 AM".

 

[Rocky_H]

And just like physical size and engine power have steadily increased, battery capacity will also.

I forgot to even mention that factor, but this very thing NEGATES the need for faster and faster home charging speeds. As vehicles get 500 and 600 and 800 mile range, you have much MORE leftover when you return home and plug in. That's even LESS miles that you need to refill overnight, requiring LOWER power!

 

[Gauss Guzzler]

The charge rate that you need has nothing to do with the battery size - it has to do with the vehicle's efficiency and usage.

A typical commute in a sleek sedan may only require a 32A overnight charge once every 4-8 days. But a job-site pickup truck towing a trailer all day is going to need 60A or more every night.

I'd still caution against spending too much money on "future-proof" AWG 4 copper though - There's no guarantee that chargers over 48A will ever come back. Tesla discontinued their 80A products for a reason and it may be that they are expecting future building code restrictions.

 

[Frank99]

I forgot to even mention that factor, but this very thing NEGATES the need for faster and faster home charging speeds. As vehicles get 500 and 600 and 800 mile range, you have much MORE leftover when you return home and plug in. That's even LESS miles that you need to refill overnight, requiring LOWER power!

As a practical matter, you're absolutely right.

But most people put "practical" and "rational" in a locked drawer when it comes time to purchase a car or truck. How many people have we heard argue that 300 miles isn't enough range, because on the spur of the moment some time in the future they might need to drive to Disneyland without stopping to charge?

 

[widget_pilot]

Ended up talking to 5 or 6 electricians over the last few days. Some came out for an estimate and some took the information over the phone. Most quotes ranged from $225 to $600, with one guy wanting over $1000.

I ended up picking the established company with good reviews and includes the inspection. $375 and will be using an industrial outlet.

 

[Dmagyar]

An outlet for charging an EV requires (most of the time) a GFCI protected outlet - generally this is done with a GFCI circuit breaker. That'll cost you $100-$150 at Home Depot.
A cheap Levition 14-50 outlet is about $10 ($20 with cover plate/box) at Home Depot. The Tesla recommended industrial-quality Hubbell 9450A or Cooper 5754N is $150 (with cover plate and box). The Bryant 9450R has been recommended as being equivalent to the Hubbell, at half the price. Question your electrician about which outlet they're planning on installing.
AWG 6 wire is about $4 / foot for the 4 wires you'll need. AWG 4 (which is good for 70 amps) will be about $8 / foot, and isn't a bad idea for future-proofing especially for such a short run. You'll also need conduit and fittings.

That's a long-winded way of saying that installing a 14-50 outlet is going to cost:
$150 - GFCI Breaker
$ 80 - High-quality outlet (Bryant), box, and cover
$ 60 - Wire to go 10 feet with usable service loops ($120 if you use AWG 4)
$ 15 - conduit and fittings
----
$300 for the hardware.

The electrician SHOULD pull a permit and get an inspection. I have no idea how much that'll cost. Let's guess $100.

It'll probably take a couple of hours to do the installation. Call it $150-$250 for labor.

So, something on the order of $600 seems like a minimum cost for a high-quality, permitted installation. Perhaps $100-$200 cheaper if the electrician was planning on using a cheap outlet and works fast.

How can you reduce costs?
- You could tell the electrician that you want the 14-50 outlet for a welder. That means you may not need a GFCI breaker; a normal breaker is $15. Some towns may not require the GFCI outlet for EV charging, if you live in one of those this is a no-brainer.
- You could use a cheap outlet, like the $10 Leviton at Home Depot. If you use a cheap outlet, make sure the electrician uses a torque wrench to tighten the screws holding the wires to the outlet; if he just uses a screwdriver, you run the risk of overheating and melting the outlet (or starting a fire).
- You could find an electrician who will do the job without a permit/inspection. ummm...yeah...not a good idea. Someone who's willing to do this is likely willing to cut other corners that you really don't want cut.

Also if reducing fully the overall costs, note the neutral and ground wire certainly don’t have to be #4, ask your electrician, he’ll be able to tell you what size he’ll be installing…just sayin.

 

[Gauss Guzzler]

The neutral wire carries full current (when it's used) so it always has to be the same size as the hot conductors. Ground is #10 for 30A-60A circuits but the electrician will know that.

 

[Andy7]

I decided to use the Tesla charger for two reasons. The main one was that if something goes wrong between the charger and the car, I only have to deal with Tesla. They can't cay it's not the car go talk to whomever. The other is that several of the non-Tesla chargers were more expensive than Tesla's. If I were contemplating adding a second non-Tesla EV, I might have considered another brand charger.

 

[Dmagyar]

The neutral wire carries full current (when it's used) so it always has to be the same size as the hot conductors. Ground is #10 for 30A-60A circuits but the electrician will know that.

Please explain how that neutral carries any current when the charging circuit uses 240 volts? I’m eagar to learn this exciting new Electrical concept. Include the NEC code section to save us verifying your claim.