How to charge Model S at home?

[beatle]

1. Ah, I thought the HPWC also needed the breaker. My receptacle was for my recently decommissioned arc welder anyway...
2. Wow, I see the cost of wire has more than doubled since I did an install. Looks like a roll of 6/2 is ~$125 and 6/3 is ~$250. Sheesh.
3. I'd agree with that if you're actually going to be plugging/unplugging the UMC frequently, but if this is the equivalent of a HPWC install that is semi-permanent (and it is) then it won't be messed with any more than your stove which doesn't need such a pricey receptacle.
4. I took this for granted since the 14-50 came with my car. If you buy a second UMC, you can buy whatever adapters you need which may or may not include a 14-50.
5. I had access to a 3d printer so this was negligible, though I'd need the remote holder for the handle either way since my receptacle is at one end of the garage and the charge port is at the other. These are nice: Tesla Charge Holder - Mobile Connector Bracket by hamiltont and Tesla Mobile Charger Holder by Cantyoudobetter

So the cost is not as black and white anymore as before the wiring cost shot up and before someone decided that EVs were different than RVs. Still having the freedom to replace a faulty connector is worth something, as is the ability to sell it and leave a receptacle if/when the time comes to move on.

 

[DerbyDave]

And because I get nervous when I see this from people, this was wire in conduit instead of Romex? 6 gauge would be OK if that is individual wires in conduit, but not if it's NM-B cable for a 60A circuit.

Electrician only used a small amount of conduit, as wire was in inaccessible areas except a run thru a closet up to attic area. The type of wire, I am not sure. I think it was THHN or maybe Romex? All 3 insulated copper wires were within one jacket, if that helps. The calculator at the bottom of this page shows that was within spec. I had 2 electricians here.

Electrical Wire & Cable Size Calculator (Copper & Aluminum)

 

[Rocky_H]

3. I'd agree with that if you're actually going to be plugging/unplugging the UMC frequently, but if this is the equivalent of a HPWC install that is semi-permanent (and it is) then it won't be messed with any more than your stove which doesn't need such a pricey receptacle.

Eh, the difference is more than just the spring wear from plugging and unplugging. The wire connection lugs in the back are really bad on the Leviton compared to the others, and are much more likely to not get the wire pinched in well or to get the screws tightened enough. So there is a really increased likelihood of a bad installation with the Leviton. And as pointed out with your oven example, you can be more tolerant of that kind of thing with appliances that cycle on and off for short periods of time. You really don't want that kind of thing with high load for extended hours of time, so it is pretty important to use a better receptacle in this use case that isn't an oven.

4. I took this for granted since the 14-50 came with my car. If you buy a second UMC, you can buy whatever adapters you need which may or may not include a 14-50.

Yeah, when that used to come with it, that's what got everyone defaulting to that. It doesn't come with it now, but I think it's unfortunate so many people are stuck in that thinking. A 14-30 or 6-20 might be an appropriate choice, depending on people's electrical situation, but the zombie hordes keep repeating, "14-50, 14-50...".

The type of wire, I am not sure. I think it was THHN or maybe Romex?

Well, that matters, because one is a code violation and one isn't.

All 3 insulated copper wires were within one jacket, if that helps.

Yes, that bundled wires together inside a jacket like that is NM-B, which is called Romex. So now we have the answer. 6 gauge of that is not rated for a 60A circuit, so yes, this is a code violation.

The calculator at the bottom of this page shows that was within spec. I had 2 electricians here.

Electrical Wire & Cable Size Calculator (Copper & Aluminum)

No, unfortunately it does not show that. That calculator is for copper wire, like wire in conduit. That has a different rating than for that bundled cable, where the wires are all packed tightly together with an insulating sheath of plastic insulation around it trapping the heat in together. That has a lower current rating. Here, this rating chart makes it really straightforward:

Cerrowire Resources - Ampacity Charts

Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.

www.cerrowire.com

This chart shows for each wire type and wire gauge, how many amps the rating allows. The first column says NM-B; that is Romex cable like you have. The second column is for separate wires that are run in conduit that have more air space around them for cooling.

See the 6 gauge row? See how it says the Romex is rated up to only 55A? The wires in conduit are allowed up to 65A. So that is why 6 gauge Romex can't be used for a 60A circuit.

 

[DerbyDave]

The maximum use is 48 A. This is why Tesla specifies 6 in the installation manual. That is 60A peak, 48 A continuous is allowed. I have looked up on Southwire site, and this is allowable, and Tesla says it is allowable, and my electrician obviously disagrees with you, because he also says it is allowable.

 

[ucmndd]

The maximum use is 48 A. This is why Tesla specifies 6 in the installation manual. That is 60A peak, 48 A continuous is allowed. I have looked up on Southwire site, and this is allowable, and Tesla says it is allowable, and my electrician obviously disagrees with you, because he also says it is allowable.

Maximum use is 48 amps continuous, so you must multiply it by 1.25 to determine the necessary ampacity rating of the wire (60 amps). Since 55 is less than 60, you cannot use #6 NM-B wire in this scenario per NEC.

Your interpretation is wrong.

As usual, Mike Holt to the rescue on this one:

#6 NM-B on 60 amp breaker for 48A EVSE

I have been asked to connect an EVSE to an existing piece of 6/2 NM-B (ROMEX) in a new home that was installed by the home builder. the EVSE has a draw of 48 amps, so the breaker needs to be 60 amp (48 x 1.25 = 60). My understanding is that a continues load (the charger will be drawing maximum...

forums.mikeholt.com

Are you gonna burn your house down? Nah. Is it code compliant? Definitely not.

 

[ucmndd]

As for your assertion that “Tesla says it is allowable”, that is false, as the Gen 3 wall connector manual says “if installing for max power use minimum 6 awg, 90C rated copper wire for conductors.”

Since ALL NM-B wire must be used at the 60C rating, 6 AWG does not meet the stated requirements.

Speaking to the electrician, it sounds like he also ran some of this cable through conduit, which is yet another no-no, so I’m not sure we can trust his judgment.

 

[DerbyDave]

I appreciate all the input. The large contractor I worked with is a very well established company. The company had one electrical contractor come out and estimate and plan the installation, and two electricians install it after I accepted the estimate. I'll have to rely on them to have done the right thing. Thanks.

 

[Rocky_H]

Speaking to the electrician, it sounds like he also ran some of this cable through conduit, which is yet another no-no, so I’m not sure we can trust his judgment.

That is allowed, and is actually a good and proper thing in some places. Let's say you are running most of the run above ceilings and inside a wall, which is where you normally use Romex. And then you need to come out of the wall and go along the outside exposed surface of the wall for a few feet to the final mounting location. Code requires that the Romex isn't allowed to be exposed on an outer surface like that, so to meet code, you DO put it in a little bit of conduit for that, and that is allowed.

 

[DerbyDave]

That is allowed, and is actually a good and proper thing in some places. Let's say you are running most of the run above ceilings and inside a wall, which is where you normally use Romex. And then you need to come out of the wall and go along the outside exposed surface of the wall for a few feet to the final mounting location. Code requires that the Romex isn't allowed to be exposed on an outer surface like that, so to meet code, you DO put it in a little bit of conduit for that, and that is allowed.

That was what we did. Instead of having the 240V bare wire run from the floor to the ceiling inside of a closet, we chose to protect the wire from anyone or anything accidentally disturbing the wire. It was 7 feet of wire in conduit out of the 100-125 feet. It was the right thing to do.

 

[DerbyDave]

Why is it that electrical codes are so subject to interpretation? I see on my searches that electrician 1 says something isn't allowable, and electrician 2 says it is. Are electricians always interpreting things differently, is something lost in training or education, or are the codes so undefined? I am not in a position to determine the proper installation. If I cannot rely on the certified electricians in my area, (multiple companies gave me the same estimate using the same wire and materials) am I to rely on unknown people on the Internet for advice? What would you do?

 

[WaukeshaTG]

Why is it that electrical codes are so subject to interpretation? I see on my searches that electrician 1 says something isn't allowable, and electrician 2 says it is. Are electricians always interpreting things differently, is something lost in training or education, or are the codes so undefined? I am not in a position to determine the proper installation. If I cannot rely on the certified electricians in my area, (multiple companies gave me the same estimate using the same wire and materials) am I to rely on unknown people on the Internet for advice? What would you do?

Electrical codes can be dang frustrating. I always undershoot, just to be safe. I have a 6-50 outlet on a 50amp breaker, with 6/2 romex. My run is about three feet off of the panel.