50A NEMA on 60A SubPanel

[Cosmacelf]

Do you think a 40 or even 30a NEMA would still be too much on the subpanel though?

That subpanel can't handle any 240V loads, no need to do a load calculation. That's a lot of circuits for 60A.

So yes, your only option is to run a circuit from the main panel. I would strongly recommend hard wiring a Wall Connector instead of a receptacle/GFCI breaker. It is more robust, fewer points of failure. For future proof reasons, have him run a 60A circuit (tell him to use 6/2 MC cable, or else he will likely use non-code compliant 6/2 NM-B/Romex).

Alternatively, buy a Mobile Connector, 50A GFCI breaker and high quality NEMA 14-50 receptacle (where the electrician can use 6/3 NM-B/Romex).

 

[EVer Hopeful]

I'm also worried about future upgrades as well if I get a car that can draw more than 32a.

I keep saying this, but who cares what the car draws? Unless you're using it as an Uber (in which case use a SC anyway) you simply charge it overnight and 32A is more than enough for that. You can probably even manage with less than that!

Why do people keep focusing on getting as much power into the car as quickly as possible? It's not necessary


(not meant to be a personal attack on you btw )

 

[Cosmacelf]

I keep saying this, but who cares what the car draws? Unless you're using it as an Uber (in which case use a SC anyway) you simply charge it overnight and 32A is more than enough for that. You can probably even manage with less than that!

Why do people keep focusing on getting as much power into the car as quickly as possible? It's not necessary

Not Necessary, 99% of the time. Occasionally, you’ll need to charge during the day (coming back home mid day after a long drive, needing to go out again in the evening), and when you do, 48A is nice. Still not a must have, but nice.

And the larger a vehicle you have, the more “nice” this becomes, for instance a Cybertruck which will suck back those electrons, in comparison.

 

[DuncanM]

I keep saying this, but who cares what the car draws? Unless you're using it as an Uber (in which case use a SC anyway) you simply charge it overnight and 32A is more than enough for that. You can probably even manage with less than that!

Why do people keep focusing on getting as much power into the car as quickly as possible? It's not necessary


(not meant to be a personal attack on you btw )

Adding to the above.

How many miles do you drive in a week? If you have 12-2 wire going to the garage/carport then the most cost effective upgrade is likely a 20amp 120v breaker feeding [which you already have] a NEMA 5-20 outlet [simply replace one existing outlet], and then charging at 120v/16a. 10 hours of charging at 120v/16a will give you about 60-70 miles of added range nightly.

You have to consider the cost of upgrading the panels and adding capacity for a 60 or 50amp 240v breaker vs how many miles of EV driving that cost would cover.

 

[brkaus]

I keep saying this, but who cares what the car draws? Unless you're using it as an Uber (in which case use a SC anyway) you simply charge it overnight and 32A is more than enough for that. You can probably even manage with less than that!

Why do people keep focusing on getting as much power into the car as quickly as possible? It's not necessary


(not meant to be a personal attack on you btw )

it's very situational.

Length of commute
Number of EVs in the household (now and in the future)
Cost of labor vs parts

If it's only marginally more to get a larger circuit, I'd do it. But if it starts adding costs like upgrade the main circuit panel, I'd try to do best I could. (unless the panel is dangerous).

 

[EVer Hopeful]

Occasionally, you’ll need to charge during the day (coming back home mid day after a long drive, needing to go out again in the evening)

[forgot to press send again here]


It has a 300 plus mile range (allegedly)

mid day to the evening gives you four, maybe six hours


(again, not trying to pick a fight. I think we're mostly in agreement, here)

 

[doghousePVD]

I keep saying this, but who cares what the car draws? Unless you're using it as an Uber (in which case use a SC anyway) you simply charge it overnight and 32A is more than enough for that. You can probably even manage with less than that!

Why do people keep focusing on getting as much power into the car as quickly as possible? It's not necessary


(not meant to be a personal attack on you btw )

Depends on the situation. I have needed to charge midday multiple times, especially when I get an unexpected trip. Glad I have a 72 A charger in my X. No SC within 50 miles.

Other folks have different situations. I tire of commenters frequently saying you CAN/MUST live on 15 amp or whatever. Some can, others cannot easily. It all depends.

 

[miimura]

It would be best to pull a line for a dedicated circuit from the main panel. Even better, get a quote for two dedicated circuits from the main panel if there is a chance you might get a second EV. The cost for materials scales with the additional circuit but the labor cost may not be that much different.

No, two dedicated circuits is not better. What is better is to install a sub-panel in the garage. If you're going to pull a new circuit through the attic, you might as well make it a big one. The OP has 200A service and lots of spare capacity in the main. Why not pull a 100A circuit to a sub-panel in the garage. That way you could install many different combinations of charging for multiple vehicles with little subsequent cost after the sub-panel was installed.

 

[Whatstreet]

No, two dedicated circuits is not better. What is better is to install a sub-panel in the garage. If you're going to pull a new circuit through the attic, you might as well make it a big one. The OP has 200A service and lots of spare capacity in the main. Why not pull a 100A circuit to a sub-panel in the garage. That way you could install many different combinations of charging for multiple vehicles with little subsequent cost after the sub-panel was installed.

Get quotes both ways. A sub panel that won't be used for any other additional circuits is an unnecessary additional cost. But, that depends on the situation. If you want a sub panel then that would be the thing to do.

 

[Eric33432]

I'm wondering what the OP did. I read the entire thread; hope I did not miss.

If this was my situation, and I was worried about cost, and I did not have time of day billing (which I do not), and most of the time I have all evening and all night to charge, and I had a Model 3 RWD, I would install a Tesla Wall Connector and power it from the sub panel. I would start with a 30 amp breaker for 24 amp charging. If this was satisfactory for my driving situation, I would leave it. If not, I would only after then install a new 60 amp dedicated circuit from the main panel. The first time the 60 amp breaker that feeds the sub panel trips, I would reduce the charging to 16 amps, and begin the process of installing the circuit from the main panel, but it is likely that will never happen.

I would bet that the 60 amp breaker will never trip, and that Tesla M3 RWD will be at 100% every morning!

If you want to do a load calculation for the sub panel, it is complicated in that it is a combination of a continuous load (the EVSE), and the rest of the circuits which are non-continuous loads. The load calculate app I have (Mike Holt's Electrical Tool Box) only does load calculations for the entire house, not a part of the house.

I understand the TWC can now be purchased at Best Buy, at least where I live.

 

[Acps110]

I'm wondering what the OP did. I read the entire thread; hope I did not miss.

If this was my situation, and I was worried about cost, and I did not have time of day billing (which I do not), and most of the time I have all evening and all night to charge, and I had a Model 3 RWD, I would install a Tesla Wall Connector and power it from the sub panel. I would start with a 30 amp breaker for 24 amp charging. If this was satisfactory for my driving situation, I would leave it. If not, I would only after then install a new 60 amp dedicated circuit from the main panel. The first time the 60 amp breaker that feeds the sub panel trips, I would reduce the charging to 16 amps, and begin the process of installing the circuit from the main panel, but it is likely that will never happen.

I would bet that the 60 amp breaker will never trip, and that Tesla M3 RWD will be at 100% every morning!

If you want to do a load calculation for the sub panel, it is complicated in that it is a combination of a continuous load (the EVSE), and the rest of the circuits which are non-continuous loads. The load calculate app I have (Mike Holt's Electrical Tool Box) only does load calculations for the entire house, not a part of the house.

I understand the TWC can now be purchased at Best Buy, at least where I live.

Model 3 RWD only has a 7.6 kW on-board charger (32 Amps continuous) versus 11.5 kW on-board charger (48 Amps continuous) in Long Range and Performance trims. No need to put in a 60 Amp circuit breaker for a RWD as it only needs a 40 Amp circuit breaker to max out its on-board charger at 32 Amp. (Although it won’t hurt anything to plug a RWD into a larger circuit.)

 

[Whatstreet]

Model 3 RWD only has a 7.6 kW on-board charger (32 Amps continuous) versus 11.5 kW on-board charger (48 Amps continuous) in Long Range and Performance trims. No need to put in a 60 Amp circuit breaker for a RWD as it only needs a 40 Amp circuit breaker to max out its on-board charger at 32 Amp. (Although it won’t hurt anything to plug a RWD into a larger circuit.)

Think of the future when doing these home infrastructure projects.