Non-Tesla owner wants to rent a Tesla for a day, but questions...

[HRS2403]

I've just installed a Level 2 NEMA 14-50 receptacle in my garage for a future EV (or arc welder!).

1) I'm thinking of renting a Tesla on Turo for a day. I see from discussions here that if I just want to drive the car, the owner can lend me the keycard. If it's easy for the owner to add me as a driver, that would be fine. Do I have things correct?

2) As far as charging at home, I'd be using my Level 2 receptacle with the owner's Mobile Connector. Can I simply plug the connector into my receptacle, or is it more involved?

Thanks from a possible future Tesla owner...

 

[Rocky_H]

It's a NEMA 14-50 now, with 6/3 gauge NM-B. I was thinking ahead to the possibility of changing out the NEMA for a Tesla Wall Connector, with its max 48A charge current. (60A 80%-derated to 48A). Yes, the electrician should have known better.

Ah, yeah. For these kinds of look ahead scenarios, it's allowed to oversize the wire if you want to from the start, since that is the part that is labor intensive to have to change later. And that would allow to just swap the ends of the breaker and the device later. But with the 6/3 Romex already in, the 50A rating is what you will have to stick with. And that's really not bad at all! If you want the look or convenience of a wall connector later, it can be configured for a 50A circuit anyway.

 

[HRS2403]

(Replying to Rocky_H)

Well, I'd like to get the maximum charge rate, probably like most anybody, but safely.

So, getting to that magical 60A circuit would mean--if I understand the ampacity calculator correctly--4/3 NM-B, which would be prohibitively expensive (about $2000 for 125', about 4x the price of 6/3).

 

[Rocky_H]

Well, I'd like to get the maximum charge rate, probably like most anybody, but safely.

So, getting to that magical 60A circuit would mean--if I understand the ampacity calculator correctly--4/3 NM-B, which would be prohibitively expensive (about $2000 for 125', about 4x the price of 6/3).

Yeah. Here's the table I usually reference. It's the first one that comes up on a Google search on "ampacity table".

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

NM-B is that first column at 60 degrees C. Individual wires in conduit is the second column at 75 degrees C.
The first place that can meet the spec for a 60A circuit is either NM-B at 4 gauge or wire in conduit at 6 gauge. Yeah, 4 gauge NM-B gets kind of crazy expensive. The 6 gauge wire in conduit would be cheaper but a lot more work in some cases, where NM-B is made to just stick inside walls and above ceilings without needing to build conduit for it. So I like where you're at for cost effectiveness.

 

[Randy-12]

(Replying to Rocky_H)

Well, I'd like to get the maximum charge rate, probably like most anybody, but safely.

Which model of Tesla are you looking at purchasing?

They can't all take the full amount of power you seem to be wanting to supply.

IMHO 50 Amps is more than enough for 98% of the charging anyone would use and most of us can get through very well with much less than that.

 

[HRS2403]

Which model of Tesla are you looking at purchasing?

They can't all take the full amount of power you seem to be wanting to supply.

IMHO 50 Amps is more than enough for 98% of the charging anyone would use and most of us can get through very well with much less than that.

Well, if I did, probably a Model 3, and I'd probably just use the Mobile Connector, which "only" charges at a max of 32A anyway. Possibly someday a Wall Connector, charging at 40A.

 

[HRS2403]

Yeah. Here's the table I usually reference. It's the first one that comes up on a Google search on "ampacity table".

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

NM-B is that first column at 60 degrees C. Individual wires in conduit is the second column at 75 degrees C.
The first place that can meet the spec for a 60A circuit is either NM-B at 4 gauge or wire in conduit at 6 gauge. Yeah, 4 gauge NM-B gets kind of crazy expensive. The 6 gauge wire in conduit would be cheaper but a lot more work in some cases, where NM-B is made to just stick inside walls and above ceilings without needing to build conduit for it. So I like where you're at for cost effectiveness.

Yes, that's the one I've used. Actually I had a pretty clear, straight shot from the basement panel to the garage, about 75'. It would not be cheap to do all over again with 3x THHN cables in conduit, but at least there's no structural element in the way. Nonetheless, for the additional 8A (to max out the Wall Connector's charging rate), it's not worth the added expense, for me at least.