FAQ: Home Tesla charging infrastructure Q&A

[FlatSix911]

Thanks for your reply. Yes, I plan to make the connection inside a receptacle box behind the dryer.

 

[Max*]

I'm back (original question: FAQ: Home Tesla charging infrastructure QA - Page 22)

So I've gotten a few quotes, and realized I'm likely doing this myself. One of the quotes had an interesting comment in it, and I wanted to run it by you:

The enclosure for the NEMA 14-50 is tricky. The TESLA mobile connector is about 6” long. Most electricians will just install a standard outdoor electrical outlet with a weather proof cover. Unfortunately this will not satisfy the “in-use” code. This code states that if an electrical appliance is plugged in outside the plug must be completely sealed when in use. The standard weather proof cover will not close all the way when the 6” TESLA cord is plugged in. When I install these outlets outside I modify a NEMA 3R cabinet to accepted a NEMA 14-50 outlet and be completely closed when in use. The cabinet is even lockable.

Is he correct about the "in use" code (NEC?). Does that mean if I do it myself I also need to modify the NEMA 3R enclosure?

He included this pic as an example:

 

[FlasherZ]

Is he correct about the "in use" code (NEC?). Does that mean if I do it myself I also need to modify the NEMA 3R enclosure?

This is going to be one of those "it depends on the inspector" cases.

406.9 (NEC 2014) describes the requirements for receptacles in damp or wet locations. 406.9(A) says that a receptacle is protected from the weather when under an overhang and is not subjected to a beating rain or water run-off. 406.9(B)(2)(b), for wet locations, says that when the load connected is attended, you only need weather proof when the receptacle is closed, and 406.9(B)(2)(a) says that when the load is unattended, an "in-use" cover must be applied.

The NEC's definition of "damp location" is "locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture. Examples of such locations include partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements, some barns, and some coldstorage warehouses."

You can probably make two arguments here: The overhang created by a temporary receptacle box is sufficient enough to call it a "damp location" versus a "wet location" because it protects the receptacle from beating rain, but I can see some - or perhaps many - inspectors arguing that it isn't sufficient. You can also argue that your car is "attended" while charging because you're present on-premise.

That box is a relatively good idea, if not a little overkill (with the unistrut). It also helps with the code requirement for EVSE's required to be "fastened in place" in the 2014 NEC, since the box supports the EVSE. If you plan to keep a UMC permanently plugged into this outlet and rarely unplug it, then this box is an even better idea because the UMC will remain plugged in when "unattended".

 

[Max*]

Thank you again for your knowledge and time!

 

[GreenT]

Why not just use

GE 50-Amp Temporary RV Power Outlet-U054P - The Home Depot

 

[Max*]

Why not just use

GE 50-Amp Temporary RV Power Outlet-U054P - The Home Depot

That was my original intent (i linked that exact thing when asking the question here).

But the electrician said that with the Tesla plug, it won't close or be watertight...

 

[FlasherZ]

For what it's worth, I've used the Eaton model I linked above for a few years now and never have I encountered water beating against the receptacle; the inside surface of the box has always been bone dry even in our crazy storms here.

 

[Max*]

One more question, this time it's not about the install, but ethics I guess.

I've had 3 range of quotes.
-Tesla approved $1200-$1600, including permit
-Licensed Electrician $700-$800, including permit
-Licensed Electrician $400-$600, as soon as I ask if the permit is included or I need to get it myself, these guys stop replying to emails/phone calls

For the last group of electricians, aren't they risking their license or some punishment if he does the work without a permit?

 

[FlasherZ]

For the last group of electricians, aren't they risking their license or some punishment if he does the work without a permit?

Yes, from what I see in the Virginia code, monetary fines of up to $10,000 if caught. If they do the work correctly, there is little chance they'll get caught. They'd have to really botch the install, forcing you to go to another contractor and make you angry enough to file a complaint, which turns into an investigation, referring it to the licensing board for discipline, etc. In addition, depending upon the state and municipality, there are different places these things are handled -- municipal courts, the state licensing board, etc.

I can't speak with much experience in the licensing area, because in Illinois and Missouri there is no state licensing of tradesmen, with one exception: roofers (needed for the ones who swoop in after nasty hail storms). Municipalities can set their own rules by ordinance and establish their own licensure programs. As you can imagine, it's slightly riskier, but jobs like yours are considerably less expensive here (note I don't speak for Chicagoland, where everyone involved lines up for their entitlement to your money).

Most of the time, you'll find that many electricians (at least the ones who have been around for a while) do good work even if they skip the permit / inspection step; this is because they know the threat of getting caught can turn their couple-hundred-dollars profit into a several-thousand-dollar loss. As long as you don't knowingly instruct the contractor to continue without a license, the failure to obtain permits is on the contractor, not you, unless it's your responsibility in the contract. Out here, I tell people to go with someone locally, who's been in business quite a while.

From an ethics standpoint, I take issue with permits needed for small, simple work. It adds at least a few hundred dollars to the smallest of jobs and expends even more taxpayer money on the back end. The NEC still dictates workmanship standards and is codified in law, so there is recourse available. With that said, I would never knowingly and willingly tell a contractor to skip a required permit and inspection - too much liability.

 

[Max*]

Thank you, yet again, for your reply!

 

[robby]

FlasherZ: In your FAQ you warn against a 6-20 to 14-50 adapter for folks with a 20A 240V air conditioner outlet. I agree 6-20 to 14-50 is dangerous because of overdraw if someone forgets to dial down amps, but what about building a 6-20 to 5-20 adapter? Though you should make it VERY CLEAR that the 5-20 receptacle is NOT to be used as a 120V receptacle, this seems like a good solution to me. The UMC will take the 240V even though the 5-20 adapter is intended for 120, and the wired resistor will indicate to it a breaker setting of 20A. Thus you get all of the benefit of the 240/20 wiring without risk of overdraw. What do you think of this?

 

[FlasherZ]

FlasherZ: In your FAQ you warn against a 6-20 to 14-50 adapter for folks with a 20A 240V air conditioner outlet. I agree 6-20 to 14-50 is dangerous because of overdraw if someone forgets to dial down amps, but what about building a 6-20 to 5-20 adapter? Though you should make it VERY CLEAR that the 5-20 receptacle is NOT to be used as a 120V receptacle, this seems like a good solution to me. The UMC will take the 240V even though the 5-20 adapter is intended for 120, and the wired resistor will indicate to it a breaker setting of 20A. Thus you get all of the benefit of the 240/20 wiring without risk of overdraw. What do you think of this?

Indeed this is the right way to handle this particular situation (until Tesla starts producing more adapters). Label it 6 ways to Sunday, because I do know from first-hand experience that a 120V Shop Vac works for about 3.21 seconds at 240V, and does an INCREDIBLE job at vacuuming for that short period of time.

(No, not my fault - the former owner of a property we purchased decided he wanted a receptacle in a basement room, and simply disconnected the baseboard heat and connected it to an outlet. I suspect he used switched-power-supply electronics there (where 240V works just fine), and didn't realize he had actually wired the outlet with 240V, along with never plugging in a 120V-only device. The white had not been remarked to black.)

 

[Max*]

Last question (I hope). I had the electricians come out and do the work. They installed the outlet about 2" off the ground in the carport (the carport is probably another 6" up from the driveway (another project for a different day), thus water intrusion is not a concern).

They offered to put it higher, but they also warned me that it would require more drywall repair than I would have liked on the main level (whereas this way most of the work stays in the basement).

Everything works fine, just for my own curiosity are there any code violations/risks associated with the plug being so low?

Thank you again for all your insight and help!

 

[TexasEV]

FlasherZ: In your FAQ you warn against a 6-20 to 14-50 adapter for folks with a 20A 240V air conditioner outlet. I agree 6-20 to 14-50 is dangerous because of overdraw if someone forgets to dial down amps, but what about building a 6-20 to 5-20 adapter? Though you should make it VERY CLEAR that the 5-20 receptacle is NOT to be used as a 120V receptacle, this seems like a good solution to me. The UMC will take the 240V even though the 5-20 adapter is intended for 120, and the wired resistor will indicate to it a breaker setting of 20A. Thus you get all of the benefit of the 240/20 wiring without risk of overdraw. What do you think of this?

You don't need to build it. EVSEadapters.com sells one.

 

[FlasherZ]

No requirement in a residential garage.

If commercial, ADA can apply and that would stretch the definition of "accessible".

De facto "standard" is 48" from floor for non-15/20A receptacles.

 

[FlatSix911]

Flasher, thank you for providing this great FAQ resource to the TMC members!

After reading the thread, I am ready to install a HPWC in my garage and have a few questions:

1. I only have a 240V/30 Amp circuit available, so the electrician has recommended 24 Amp charging?
2. He recommended running 10 Awg wire to the new HPWC which is a 50 foot run in the garage?
3. Would you recommend running the new wires in a conduit or go with cheaper NM cable?
4. Any other suggestions? I want to minimize the cost and can live with 17Mph charging.

Thanks

You don't have to use that 30 amp breaker. You can swap it out for a bigger breaker. Not sure why you wouldn't at least use a 50 amp breaker.

I should have mentioned that the existing 30A circuit to the Dryer uses 10 Awg wire.
I am planning to extend the unused Dryer circuit to the garage to service the HPWC.

My answers are based upon what you have written here, plus - based on your clarification - that you're going to extend the dryer circuit from your laundry room to the garage, instead of running new wire all the way from the panel. Based on that assumption:

1) yes, on a Wall Connector configured for 30A, the charge current will be 24A; this is because a circuit must be sized at 125% of the offered load. 24 * 125% = 30A.
2) yes, a 30A circuit requires a #10 copper conductor
3) this can vary by code... if running inside the walls, NM cable is just fine unless code prohibits it (Chicagoland and some NY localities). If running on the surface of walls, NM cable must be protected from "physical damage", a term interpreted by AHJ's. The most common interpretation requires the NM cable be encased in an EMT sleeve and fittings anywhere below a line drawn 7' above the floor surface. So if your plan is to have the cable run on the surface of walls, you'll likely use some form of conduit anyway to protect it from damage.

The plan you are envisioning is likely the lowest-cost approach. Your connection to the existing 30A circuit must be made inside a junction box or wall box with an appropriate cover -- will you be making it inside a receptacle box behind the dryer?

Here are a few photos of the final installation (both HPWC & MC plug). The bypass is required to switch between the Dryer and the EV charger.

 

[FlatSix911]

I forgot to include the most important part of the finished installation ... the cool new EV charger decals :wink:

http://www.ebay.com/itm/EV-EVSE-Ele...2-5-/321792396927?hash=item4aec524e7f&vxp=mtr

 

[comegetme]

Conduit elbows for #6, #2 conductors

What is the maximum bend radius of a PVC conduit for three #6 conductors and a ground wire (for a NEMA 14-50 outlet), and 3 #2 conductors and a ground wire (for HPWC), respectively, such that the conductors can be pulled? The conduit run is 50 feet.

 

[FlasherZ]

What is the maximum bend radius of a PVC conduit for three #6 conductors and a ground wire (for a NEMA 14-50 outlet), and 3 #2 conductors and a ground wire (for HPWC), respectively, such that the conductors can be pulled? The conduit run is 50 feet.

Assuming copper...

sch 40 or sch 80? Sch 40 requires 3/4" for 3x#6+1x#10, while sch 80 requires 1" for the same. NEC 352.22 says the internal diameter must not be compromised, and points you at table 2 in chapter 9. For a 3/4" conduit, maximum radius is 5"; for 1", it's 6" (from table 2).sch 80 is required where inspector would require protection from physical damage.

For HPWC, you only need 2 #3's and a #6 ground; that requires 1" conduit regardless of sch 40 or 80, so 6" bend radius; same if you go to 2x#2+1x#6. If you still want 3x#2's+#6 anyway, that would require 1 1/4", maximum bend radius 8" from table 2.

Sum of bend angles may not exceed 360 degrees without pullboxes.

Conduit fill calculator I use: Raceway Fill Calculator

 

[comegetme]

Assuming copper...

sch 40 or sch 80? Sch 40 requires 3/4" for 3x#6+1x#10, while sch 80 requires 1" for the same. NEC 352.22 says the internal diameter must not be compromised, and points you at table 2 in chapter 9. For a 3/4" conduit, maximum radius is 5"; for 1", it's 6" (from table 2).sch 80 is required where inspector would require protection from physical damage.

For HPWC, you only need 2 #3's and a #6 ground; that requires 1" conduit regardless of sch 40 or 80, so 6" bend radius; same if you go to 2x#2+1x#6. If you still want 3x#2's+#6 anyway, that would require 1 1/4", maximum bend radius 8" from table 2.

Sum of bend angles may not exceed 360 degrees without pullboxes.

Conduit fill calculator I use: Raceway Fill Calculator

Thank you, FlasherZ, for your reply! I think I misphrased my question a little bit. First off, I bought already 1" conduit for the lines to my prospective NEMA 14-50 outlets, and a combination of 1-1/4" and 1-1/2" conduit for my prospective HPWC (or similar) lines. That is, I installed 1-1/2" in a masonry wall that I just built, and I'm going to extend the conduit to the house with either 1-1/4" or 1-1/2" (yet to be decided). Why those conduit sizes? Because conduit is cheap, and another thread in this forum suggested that while #3 may be used for HPWC, #2 may result in less energy loss in the lines, and someone suggested using 1-1/4" conduit for HPWC. To be on the safe side, and to possibly make pulling easier, I put in 1-1/2" in the concrete masonry.
So far so good. Please correct me if I made a mistake or if this doesn't make sense.
I was able to locale plenty of fill calculators and tables on the internet, so I'm relatively sure I sizes the conduits correctly for the purpose. I'm also aware of the general rule that the sum of the bend angles should not exceed 360 degrees between pull points. (Surely I was referring to maximum total bend angle in a raceway, not minimum bend radius of an elbow.) However, I was informed that for thicker wires, the maximum bend angle is much less. I was told by an electrician at a big box store that the maximum for #2 wire is two 90 degree elbows, but I was not able to find authoritative confirmation for this on the internet. I was also not able to find conclusive information on the maximum bend angle (or maximum number of 90 degree elbows) is for three #6 conductors in a 1" conduit (in case the conduit size matters). If anybody has experience with this, or had a NEMA 14-50 or HPWC style installation done and knows the number of bends that the electrician used between pull points, I would greatly appreciate your help. I have trenches dug up around my house, and want to be sure to put in the conduits that can later be used to install the charging outlets without digging again