Preparing for your Model S: Selecting outlet, Solar City, etc.

[mitch672]

No. I don't have the HPWC final specs, but I'm assuming based on published information it requires a 100A circuit and wire for an 80A continuous load. Assuming 75 or 90 deg C ratings (and that you don't need de-rating), you're normally looking at #2 wire (115A/130A rating), although #3 would be good enough. It's much harder to find #3. Keep in mind this is for copper wire, usually THHN.

(#1 is hard to find too, you'd probably have to go up to 1/0 if you needed it.)

I found a source of #3 THHN, availble in different colors as well... .75 per foot, of course they only ship via FedEx, if you have a commercial address to send it to, FedEx ground isn't too pricey: 600 Volt THHN


BTW, I ordered 25' of #3 red, #3 black and #6 green from them, arrived no problem and is a major brand of wire (think it was Southwire)

 

[spatterso911]

Given what you have described, including parts it should be considerably less than that, perhaps a 1/3 of that.

PS: If you're going below the panel with the HPWC, leave yourself some room if you need additional exit from the box in the future - if you can go 18 or even 24 inches you'll be thankful later.

The HPWC would be just to the right of the panel, about a foot over, and about 5.5' high.

 

[FlasherZ]

I found a source of #3 THHN, availble in different colors as well... .75 per foot, of course they only ship via FedEx, if you have a commercial address to send it to, FedEx ground isn't too pricey: 600 Volt THHN

Also, one thing that's worth noting - if you're using these wires in wet locations (for example, outdoors -- even the inside of conduits outdoors are considered wet), you'll need THWN wire (water-resistant jacketing).

 

[atsunset]

Temporary and future rough in completed

In case you are interested, here is what I have done.
I installed a new NEMA 14-50 wall outlet for use until our HPWC shows up.

And, installed a new 100 amp circuit breaker and junction box for the new HPWC.
(The small switch panel in the middle is a generator transfer switch)

We have a 400 amp service entrance with (2) 200 amp sub panels so this was an easy addition.

One of the TESLA Ownership Experience Advocates sent me information on the HPWC.
It is 20” tall and 5 ¾” wide
It was difficult finding a wall box to fit neatly behind the HPWC with enough volume to house the wiring.
I found a 1 ¼” “LB” pull box that measures 13 ½” by 5”.
I blanked off the opening on the back and will either not use the cover or drill a hole in the cover when the HPWC shows up for final connection.

 

[FlasherZ]

In case you are interested, here is what I have done.
I installed a new NEMA 14-50 wall outlet for use until our HPWC shows up.

Looks like a good rough-in -- a couple of questions for you:

1. Do you have a ground bonding your panel's ground bus to the future HPWC box? If you have any wires that run between the two, even if they aren't hooked up, you really need a #6 ground connecting the two for safety reasons.
2. I see white tape, is this temporary? The HPWC won't need neutral, and white tape on anything but a neutral is dangerous.
3. A comment: Some inspectors will fail your 14-50 installation because the NM-B cable isn't attached to the stud. It seems silly, but the code generally requires you secure cable to a framing member. (At least I'm assuming it's NM-B, it's not allowed to be cord-type.)
4. And, just checking -- you didn't connect the 14-50 to the 100A breaker, even temporarily? I hope it's connected to a 50A breaker.

 

[atsunset]

Looks like a good rough-in -- a couple of questions for you:

1. Do you have a ground bonding your panel's ground bus to the future HPWC box? If you have any wires that run between the two, even if they aren't hooked up, you really need a #6 ground connecting the two for safety reasons.
Yes, (3) #2 wires, one is grounded on the lower ground bus in the panel.
2. I see white tape, is this temporary? The HPWC won't need neutral, and white tape on anything but a neutral is dangerous.
Yes it is temporary, I did not have green tape in my tool box, so I used it to mark the ground for later.
3. A comment: Some inspectors will fail your 14-50 installation because the NM-B cable isn't attached to the stud. It seems silly, but the code generally requires you secure cable to a framing member. (At least I'm assuming it's NM-B, it's not allowed to be cord-type.)
Yes it is NM-B cable. And I understand the code to have been attaching to framing within 4" of the box unless a clamp was used at the box. I used clamps at both locations and the distance is right at 8".
4. And, just checking -- you didn't connect the 14-50 to the 100A breaker, even temporarily? I hope it's connected to a 50A breaker.[/QUOTE]
The 14-50 is connected to a 50 amp breaker and the future HPWC is connected to a new 100 amp breaker.

Thanks for the input, I'll make sure to properly mark the ground wire with green tape.

Mike

 

[wycolo]

[atsunset] rough in completed . . .

Aarrgh, where are those pesky huge images when we really need them!?
--

 

[AMPd]

Would 400 amp (2) 200 amp sub panels be enough for 2 HPWC? Charging 2 Model S vehicles at once, both at full 80amps?

Most of the time, they'll charge at 40amps but there may be times where one of us or even both of us will need a quicker charge.

 

[FlasherZ]

Yes it is NM-B cable. And I understand the code to have been attaching to framing within 4" of the box unless a clamp was used at the box. I used clamps at both locations and the distance is right at 8".

Most reasonable AHJ's will find no fault with your installation, but if they get picky, according to code it must be supported. NEC 334.30 requires that type NM cable must be supported and secured by staples, straps, hangers, etc., within 12 in of every outlet box, junction box, cabinet, or fitting. 334.30(B) allows for unsupported cables only where it is fished between access points in concealed spaces ("old work") or some ceiling work. There is no exception for "short runs" and clamps are not considered as "supports" for that purpose.

- - - Updated - - -

Would 400 amp (2) 200 amp sub panels be enough for 2 HPWC? Charging 2 Model S vehicles at once, both at full 80amps?

Most of the time, they'll charge at 40amps but there may be times where one of us or even both of us will need a quicker charge.

I don't understand what you mean by "400 amp (2) 200 amp sub panels" - can you explain a bit more? I'm going to take my best guess in that you're saying you have a 400A service from the PoCo with 2 service panels, each connected to separate lugs on the meter base with a 200A main breaker. Most larger houses are now served this way.

In that case, it will depend upon other loads in the panels. If the circuits have been evenly distributed, you'll want 1 100A circuit for HPWC1 coming from panel 1, and another 100A circuit for HPWC2 coming from panel 2. If they haven't been distributed evenly, your electrician will likely take them from the same panel - but keep in mind you have a potential to draw 160A. Your third option is for your electrician or PoCo (depending upon who does this in your area) to upgrade your wiring and meter base, add a third set of lugs to your meter base and install a 3rd service panel in your garage, with a 200A main and 2 100A circuits for the HPWC. This is likely not the best option though because of its cost. Chances are you have room in your panels and you don't draw that much.

 

[AMPd]

Thank you Flasher, that's what I means and thank you for the answer!

 

[mnx]

So I've decided I don't need the HPWC at this time but would like to have an easy upgrade path if I change my mind in the future.

The main panel is ~20ft away from the wall of the garage where I will likely put a 14-50. Would it make sense to run heavier gauge wire now (enough to support a HPWC) and connect it to my 14-50?

The other option is that I have an unused dryer circuit in my laundry room which is adjacent to the garage. It has never been used since the house is new and I had a gas line/gas dryer installed. Would it make sense to extended this circuit and charge the car from a 14-30?

FWIW My father in law is going to be doing the work.

Thoughts?

 

[FlasherZ]

So I've decided I don't need the HPWC at this time but would like to have an easy upgrade path if I change my mind in the future.

The main panel is ~20ft away from the wall of the garage where I will likely put a 14-50. Would it make sense to run heavier gauge wire now (enough to support a HPWC) and connect it to my 14-50?

The other option is that I have an unused dryer circuit in my laundry room which is adjacent to the garage. It has never been used since the house is new and I had a gas line/gas dryer installed. Would it make sense to extended this circuit and charge the car from a 14-30?

FWIW My father in law is going to be doing the work.

Thoughts?

It depends on what your confidence level will be that you'll need >40A charging.

First, I'd forego the idea of using a 14-30 unless you're only going to do overnight charging and you don't anticipate starting your charges with anything less than 50% SOC.

For any needs > 50A (HPWC or 70A J1772 EVSE), you'll need to run conduit and use because you can't get NM-B cable in gauges greater than #6 AWG. C&W2G sells 160' of #3 for $185.60 (assuming 4 wires @ 40 ft each), plus the conduit (1 1/2") and fittings. You're probably looking at roughly $250-300.

Compare this to a 14-50 install... at Home Depot, a 50' roll of NM-B 6/3 runs $118.

Hope this helps make a decision.

Both wire sizes can be used in most 50 amp breakers, so if you install the #3 you can upgrade the breaker and receptacle later.

 

[derekt75]

SolarCity is quoting me $650 for an outlet within 40 feet of the main breaker. I live in San Jose, CA. Can I do better? I tried to ask details from SolarCity, but they told me I'd get details from them after I signed. I asked if they were using conduit or bare Romex inside the garage. What's better? I think bare Romex along a garage wall probably looks better than conduit?
I also asked if they were going to run a wire from the main panel outside into the subpanel in the garage using existing conduit, or if they were going to run new conduit from the main panel outside directly to the outlet. Again, no answer.
Lastly, I asked about getting a 2nd outlet in the garage in case I wind up with two electric vehicles at some point. They didn't seem that interested, and said the price would be double for two outlets. How much more do you think it should cost to add a 2nd outlet?

How long does the install take? If parts are less than $200, I'm wondering how the price gets up to $650. I was thinking the work could be done in less than 3 hours.

Lastly, should I put the outlet on the door side of the garage or the house side of the garage? I think it's common to put it on the house side, but if the charge port is at the back of the car, wouldn't it be better to put the outlet next to the garage door?

thoughts?
Derek

 

[FlasherZ]

SolarCity is quoting me $650 for an outlet within 40 feet of the main breaker. I live in San Jose, CA. Can I do better? I tried to ask details from SolarCity, but they told me I'd get details from them after I signed. I asked if they were using conduit or bare Romex inside the garage. What's better? I think bare Romex along a garage wall probably looks better than conduit?
I also asked if they were going to run a wire from the main panel outside into the subpanel in the garage using existing conduit, or if they were going to run new conduit from the main panel outside directly to the outlet. Again, no answer.
Lastly, I asked about getting a 2nd outlet in the garage in case I wind up with two electric vehicles at some point. They didn't seem that interested, and said the price would be double for two outlets. How much more do you think it should cost to add a 2nd outlet?

How long does the install take? If parts are less than $200, I'm wondering how the price gets up to $650. I was thinking the work could be done in less than 3 hours.

Lastly, should I put the outlet on the door side of the garage or the house side of the garage? I think it's common to put it on the house side, but if the charge port is at the back of the car, wouldn't it be better to put the outlet next to the garage door?

thoughts?
Derek

Here are my thoughts, in the order that they came to me:

I'm assuming you're talking about a NEMA 14-50R.

NM-B cable ("Romex") may be used where it is suitably protected from damage (methods in NEC article 334) but exposed Romex cannot be used where it is subject to physical damage. In general, most inspectors will call out exposed Romex below 7' as a safety concern. It should either be within a wall or a suitable conduit if it terminates below 7' above the floor.

As to whether they'd feed this circuit from the main or the subpanel in the garage, it would depend upon the size of the feeder and the current loads on the subpanel. It's much easier for a shorter run.

As for what looks better, my garage wall is a chipboard surface with schedule 40 PVC surface mounted and it looks fine. If you have drywall in the garage, PVC conduit on the surface looks fine, especially if you paint the conduit hold-downs. It's all subjective.

For 2 outlets, if you want the full current, nothing can be shared -- you'll need a new breaker, new wiring, new outlet, and new conduit (unless you want to run extremely large conduit to run 2 sets of wires). So 2x cost is appropriate.

My outlet is mounted on the door-side, to the left of the bay it is intended to service, because that's where many of the ports are being placed. The Leaf uses the front, though. So basically, "it depends."

Finally, as for $650 for a 40' circuit length: I believe that to be a reasonable price, whether Romex or THHN, because it'll either be labor costs (fishing through a wall to protect it) or conduit & fittings.

 

[derekt75]

I'm assuming you're talking about a NEMA 14-50R.

NM-B cable ("Romex") may be used where it is suitably protected from damage (methods in NEC article 334) but exposed Romex cannot be used where it is subject to physical damage. In general, most inspectors will call out exposed Romex below 7' as a safety concern. It should either be within a wall or a suitable conduit if it terminates below 7' above the floor.

As to whether they'd feed this circuit from the main or the subpanel in the garage, it would depend upon the size of the feeder and the current loads on the subpanel. It's much easier for a shorter run.

Yes, 14-50.

I guess I see the point about exposed Romex. Oh well. I can see how adding conduit would more time than just stapling down some wire.

The subpanel is pretty well used by the house. It doesn't contain the pool, air conditioners, or ovens, but the rest of the house is all run through the subpanel. I'd be surprised if they could add on 50A more off of that. Still, I'm hoping that they can run the new wire from the main panel to the subpanel through the existing channel (about ten feet long, inside the garage wall), rather than run conduit on the outside of my house. I'd pay extra for them to not need to run exposed conduit into the garage.

...
I'm surprised that the standard sized (3/4"?) electrical conduit would struggle to fit two 6/3 wires inside, but I've never played with 6 gauge wire before. (Does SolarCity use 8 gauge or 6 gauge? Another question left unanswered.)

 

[FlasherZ]

Still, I'm hoping that they can run the new wire from the main panel to the subpanel through the existing channel (about ten feet long, inside the garage wall), rather than run conduit on the outside of my house. I'd pay extra for them to not need to run exposed conduit into the garage.

6/3 is pretty large, it's about a 3/4" diameter.

I'm surprised that the standard sized (3/4"?) electrical conduit would struggle to fit two 6/3 wires inside, but I've never played with 6 gauge wire before. (Does SolarCity use 8 gauge or 6 gauge? Another question left unanswered.)

Well, you're limited by two things: there is a maximum number of conductors permitted in a raceway before you must de-rate due to temperature concerns. It's not a matter of making them fit, but also dealing with temp rise and such. When you de-rate, you effectively have to bump up the wire size, which defeats the purpose of fitting them.

As a result, individual conduits are generally run.

 

[Babylonfive]

Well, finally did the install of 14-50 in my garage - was unsure about the extra distribution box and all the rules, so I paid to have it installed.

Included:
- extra dist. panel on power ingress side of the house next to main cut off
- 50A breakers in that panel
- conduit run up that side, through brick to attic, through attic to other side (garage side)
- punch thru brick to garage
- 14-50 plug install, flush

One question : is this install 'right side up' for the tesla plug?

 

[gg_got_a_tesla]

One question : is this install 'right side up' for the tesla plug?

View attachment 12983

Uh oh... Unless the forum s/w flipped your image upside down (as seems to happen at times), you have it the wrong way around.

http://www.teslamotors.com/sites/default/files/downloads/universalmobileconnector_nema_14-50.pdf

 

[FlasherZ]

Yup, upside down. It's a simple fix, just take the screws out and turn it upside down.

Ground should be up.

 

[jerry33]

The normal way to install a 14-50 is with the "round" hole up. I'd be kind of nervous about the rest of the set up if the electrician mounted it upside down.