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Advice: NEMA 14-50 or Wall Charger

Need advice on whether I should go with a NEMA 14-50 or directly a WC. I live in the bay area, made a few quotes with the tesla recommended electrician and they came back from $1600 to $3000 (pretty crazy), with a permit.

Here's my situation:
1. The subpanel in the detached garage is not strong enough (30 amp, I think), so all of the electricians suggest installing a new wire directly from the main panel and running across the house (~70 ft).
2. Install/upgrade the 40amp circuit breaker in the main panel
3. NEMA plug with exterior rainproof enclosure.

Do you think approx. $2000 is a fair quote for this project? Should I just go directly with a Wall Charger instead? (Probably saving $ from the NEMA outlet, enclosure, and Mobile Connector)
 

RandyS

Fan of Elon
Jul 8, 2012
875
1,144
San Diego
If you do go the Mobile Connector route, don't get or allow your electrician to use a $10 Leviton receptacle sold at the big box stores. Eventually you will have issues with loose connections, melting, etc. There are threads on the forum about this, you can search for them. Get a Hubbell or Bryant 14-50 receptacle, they are much more robust for the hours-long charging you'll be doing...

I use a wall connector myself and leave the mobile connector in the car. But others use the mobile connector every day. As far as current level for your charging, you haven't really said how many miles you'll be driving every day or week...You might be able to use the 30 amp subpanel existing in your garage if you don't drive a lot of miles and keep the car charged up just fine (especially since you'll probably be charging in the midnight hour).
 

Sophias_dad

Active Member
Supporting Member
Jul 29, 2018
2,579
3,012
Massachusetts
I'm a little confused. There's apparently a 30 amp subpanel in the garage(I think?), but the electrician wants to install/upgrade a 40 amp breaker in the main panel. That implies to me you actually have a 40 amp subpanel in the garage now. Its a sad thought, but I'd also be checking what type(gauge) of wire is connecting the subpanel. There's more than zero chance it can already support 50 or 60 amps and the electrician wants to jump to 70 to justify an extra $1500 in work. I'd also probably jump it to 100 if the increase is actually needed.

But even with only a 30 amp subpanel in the garage, you should be able to get 24 amps of continuous charging, which should be plenty for most peoples purposes. What else is on the garage subpanel now? Garage door openers don't count at all.

Even if you go with upgrading the subpanel, once you add the cost of the rainproof enclosure, the WC will be cheaper than all the stuff needed for the outlet(the outlet, GFCI, enclosure, ...)

If we assume for a moment you have a 40 amp subpanel already, unless you have big loads out there, the UMC would get you 32 amps of charging(29 mi/hr). If you put a new heavier wire in to increase the subpanel to 70 amps, you'll still get exactly that 32 amps of charging from the UMC connected to a 14-50 outlet, because that's the max of the UMC. You might be doing all this work to get >MAYBE< 8 more amps of charging(aka ~29 mi/hr instead of 24 amps(~22mi/hr), if we assume you have a 30 amp subpanel, or absolutely ZERO increase if its really a 40 amp panel now.

Unless you have a real need for more charging speed or significant other loads in the garage, I'd just stick with what you have and either install an HPWC(inside or out) or outlet(inside only)
 
Here's my situation:
1. The subpanel in the detached garage is not strong enough (30 amp, I think), so all of the electricians suggest installing a new wire directly from the main panel and running across the house (~70 ft).
2. Install/upgrade the 40amp circuit breaker in the main panel
3. NEMA plug with exterior rainproof enclosure.

I'm in a similar situation. First I am new to Tesla so if anything I am saying is incorrect, please correct me but I think I have a good understanding of the charging options.
  1. You can use the Wall Connector on a 30A breaker. You're obviously not going to get charge rates that the 60A produces, but the Wall Connector is capable of pushing 15-60 breaker amps, so "subpanel in the detached garage is not strong enough" isn't really a true statement.
  2. 30A should get you 17-22 miles/hour based on your car model.
  3. I would say it depends on your driving, how much do you drive? 17-22 miles/hour is pretty solid for overnight charging. Probably looking at 11-13 hours for a full charge.
  4. The only reason why you should go for more amps is if you think you'll need to charge at a faster rate and even then, if you truly need to charge fast, you could just go to a super charger nearby (depending on how frequent those events are). You're looking at probably 60 full charge, super charge trips that would be the equivalent of this electrical work.
  5. Upgrading to a 40amp will give you a 6-7 miles/hour increase over the 30amp. If you're going to spend all this money, I would probably go for a 50 or 60 amp if possible.
  6. I would avoid the NEMA 14-50 as others have mentioned that there is overhead that will basically equate to the cost of the Wall Connector. The GFCI breaker, a quality NEMA receptacle + other materials. Plus I've read that GFCI tend to trip a lot for EV charging. The Wall Connector comes with the GFCI protection.
So it really comes down to what you need. I would say the Wall Connector is a no brainer and if you want the extra 6-18 miles/hour of charging then you will need to pay a premium.
 

Rocky_H

Well-Known Member
Feb 19, 2015
8,773
11,448
Boise, ID
You're getting good recommendations, and I'm just additional voting on a couple of things.
NEMA plug with exterior rainproof enclosure.
If you have to do an outside installation, I would never recommend doing an outlet to plug into. The wall connector is just a better sealed thing against rain. And anyway, outlets require GFCI breakers now, which are expensive and a finnicky pain in the butt, so I wouldn't want to do that anyway.

The subpanel in the detached garage is not strong enough (30 amp, I think), so all of the electricians suggest
This notion usually comes from the mistaken idea that people must have a 60A circuit. Sometimes that is their bad assumption, or sometimes it's owners starting off telling electricians that's what they need (when they probably don't).

But even with only a 30 amp subpanel in the garage, you should be able to get 24 amps of continuous charging,
Well, the 30A to the garage exists for some reason, so I'm pretty sure there are already circuits on it. So I would not consume the entire thing with the charging circuit. But it's probably small stuff on it, so I would think it's possible you might be able to do 15A of it for the charging circuit? Just having consistently available overnight charging at home is the great thing, even if the amps aren't that high, so that may be a reasonable and cheaper option if they can just take it from the garage subpanel instead of having to run a new line to the garage.
 
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I installed a 14-50, that way I can use it for other things.

And bought this cable, which can do 40A as opposed 32A for the standard mobile connector:

I bought it on eBay as Tesla didn't have it in stock.
 
Do it right the first time, Use the Tesla recommended electrician, Install the Tesla Wall Charger, and add the cost of this to the price of your first EV as an option just as you would be adding options if you were buying a Benz or a BMW. You may qualify for local, state or federal rebates?
Good point. I checked, but I don't see any rebates I could qualify for here
 
I'm a little confused. There's apparently a 30 amp subpanel in the garage(I think?), but the electrician wants to install/upgrade a 40 amp breaker in the main panel. That implies to me you actually have a 40 amp subpanel in the garage now. Its a sad thought, but I'd also be checking what type(gauge) of wire is connecting the subpanel. There's more than zero chance it can already support 50 or 60 amps and the electrician wants to jump to 70 to justify an extra $1500 in work. I'd also probably jump it to 100 if the increase is actually needed.

But even with only a 30 amp subpanel in the garage, you should be able to get 24 amps of continuous charging, which should be plenty for most peoples purposes. What else is on the garage subpanel now? Garage door openers don't count at all.

Even if you go with upgrading the subpanel, once you add the cost of the rainproof enclosure, the WC will be cheaper than all the stuff needed for the outlet(the outlet, GFCI, enclosure, ...)

If we assume for a moment you have a 40 amp subpanel already, unless you have big loads out there, the UMC would get you 32 amps of charging(29 mi/hr). If you put a new heavier wire in to increase the subpanel to 70 amps, you'll still get exactly that 32 amps of charging from the UMC connected to a 14-50 outlet, because that's the max of the UMC. You might be doing all this work to get >MAYBE< 8 more amps of charging(aka ~29 mi/hr instead of 24 amps(~22mi/hr), if we assume you have a 30 amp subpanel, or absolutely ZERO increase if its really a 40 amp panel now.

Unless you have a real need for more charging speed or significant other loads in the garage, I'd just stick with what you have and either install an HPWC(inside or out) or outlet(inside only)

I don't know.... but here's my subpanel in the garage - don't think I have a high load there, just a garage opener, some interior lights and exterior sensor lights.
 

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I'm in a similar situation. First I am new to Tesla so if anything I am saying is incorrect, please correct me but I think I have a good understanding of the charging options.
  1. You can use the Wall Connector on a 30A breaker. You're obviously not going to get charge rates that the 60A produces, but the Wall Connector is capable of pushing 15-60 breaker amps, so "subpanel in the detached garage is not strong enough" isn't really a true statement.
  2. 30A should get you 17-22 miles/hour based on your car model.
  3. I would say it depends on your driving, how much do you drive? 17-22 miles/hour is pretty solid for overnight charging. Probably looking at 11-13 hours for a full charge.
  4. The only reason why you should go for more amps is if you think you'll need to charge at a faster rate and even then, if you truly need to charge fast, you could just go to a super charger nearby (depending on how frequent those events are). You're looking at probably 60 full charge, super charge trips that would be the equivalent of this electrical work.
  5. Upgrading to a 40amp will give you a 6-7 miles/hour increase over the 30amp. If you're going to spend all this money, I would probably go for a 50 or 60 amp if possible.
  6. I would avoid the NEMA 14-50 as others have mentioned that there is overhead that will basically equate to the cost of the Wall Connector. The GFCI breaker, a quality NEMA receptacle + other materials. Plus I've read that GFCI tend to trip a lot for EV charging. The Wall Connector comes with the GFCI protection.
So it really comes down to what you need. I would say the Wall Connector is a no brainer and if you want the extra 6-18 miles/hour of charging then you will need to pay a premium.
Thanks for the input. Yeah, I don't drive that much on a per day basis; I tend to go with WC (or the newer J1772 WC for future flexibility) after reading all the comments.
 
I'm in a similar situation. First I am new to Tesla so if anything I am saying is incorrect, please correct me but I think I have a good understanding of the charging options.
  1. You can use the Wall Connector on a 30A breaker. You're obviously not going to get charge rates that the 60A produces, but the Wall Connector is capable of pushing 15-60 breaker amps, so "subpanel in the detached garage is not strong enough" isn't really a true statement.
  2. 30A should get you 17-22 miles/hour based on your car model.
  3. I would say it depends on your driving, how much do you drive? 17-22 miles/hour is pretty solid for overnight charging. Probably looking at 11-13 hours for a full charge.
  4. The only reason why you should go for more amps is if you think you'll need to charge at a faster rate and even then, if you truly need to charge fast, you could just go to a super charger nearby (depending on how frequent those events are). You're looking at probably 60 full charge, super charge trips that would be the equivalent of this electrical work.
  5. Upgrading to a 40amp will give you a 6-7 miles/hour increase over the 30amp. If you're going to spend all this money, I would probably go for a 50 or 60 amp if possible.
  6. I would avoid the NEMA 14-50 as others have mentioned that there is overhead that will basically equate to the cost of the Wall Connector. The GFCI breaker, a quality NEMA receptacle + other materials. Plus I've read that GFCI tend to trip a lot for EV charging. The Wall Connector comes with the GFCI protection.
So it really comes down to what you need. I would say the Wall Connector is a no brainer and if you want the extra 6-18 miles/hour of charging then you will need to pay a premium.

oh i see. So I can still install a WC inside the garage but just limited to a lower charging speed (up to 30 amps), I definitely prefer to have it installed inside. I don't drive that much, probably 60-80 miles a day for about 4 days in a week.
 
Need a picture of the main panel feeding that subpanel. What is the 30 amp duplex breaker in the subpanel feeding?

BTW, it sounds like you might need no electrical work at all. a 120V outlet will get you 5mi/hr.

Here is the picture of my main panel, looks like I have a 30amp breaker that goes to the subpanel. Seeing this now, is that possible to upgrade this breaker pair on my main & sub panel from 30amp to say, 60amp and shall do the work? No wiring, just upgrade the breakers at both ends?
 

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Sophias_dad

Active Member
Supporting Member
Jul 29, 2018
2,579
3,012
Massachusetts
Here is the picture of my main panel, looks like I have a 30amp breaker that goes to the subpanel. Seeing this now, is that possible to upgrade this breaker pair on my main & sub panel from 30amp to say, 60amp and shall do the work? No wiring, just upgrade the breakers at both ends?
It isn't clear why you even have a 30 amp breaker at the subpanel end.

But no, you can't just increase the breaker size for the main panel end until you (or someone) has verified the gauge of the wire between the main and subpanel.

It sounds like you have plenty of capacity at the subpanel already, for 15-20 amps at 240V, assuming that 30 amp breaker on the subpanel isn't actually being used to feed any branch circuit. That's 11-15 mi/hr of charging.
 
It isn't clear why you even have a 30 amp breaker at the subpanel end.

But no, you can't just increase the breaker size for the main panel end until you (or someone) has verified the gauge of the wire between the main and subpanel.

It sounds like you have plenty of capacity at the subpanel already, for 15-20 amps at 240V, assuming that 30 amp breaker on the subpanel isn't actually being used to feed any branch circuit. That's 11-15 mi/hr of charging.
Right, I forgot the gauge of the wire.

Anyway, sounds like I have decent amp to charge with a lower charging speed - i just got to decide whether to install a NEMA outlet or a WC directly inside the garage. This should save quite a bit of $$ from what i have been proposed - replace the breakers, put a new wire from one side of the house to another, NEMA receptacle & enclosure etc.

thank you everyone.
 

Sophias_dad

Active Member
Supporting Member
Jul 29, 2018
2,579
3,012
Massachusetts
This should save quite a bit of $$ from what i have been proposed - replace the breakers, put a new wire from one side of the house to another, NEMA receptacle & enclosure etc.
I'm confused. There should be no need to replace any breakers or replace wire running across the house if you keep within the 30 amp budget at the subpanel. I checked the subpanel and I >still< can't figure out why they'd put a 30 amp duplex breaker in there, presumably backfeeding the panel.

If the wire running from the main to the sub can accommodate 40 or 50 amps, you could get the breaker in the main panel upgraded and properly connect the subpanel(to the lugs meant for this very purpose), and then repurpose the now-useless 30 amp duplex breaker(or at least its breaker-spots) in the subpanel for your HPWC(if you want).
 
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STS-134

Active Member
Aug 8, 2021
1,818
3,147
SF Bay Area
Right, I forgot the gauge of the wire.

Anyway, sounds like I have decent amp to charge with a lower charging speed - i just got to decide whether to install a NEMA outlet or a WC directly inside the garage. This should save quite a bit of $$ from what i have been proposed - replace the breakers, put a new wire from one side of the house to another, NEMA receptacle & enclosure etc.

thank you everyone.
What's the capacity of the subpanel? Note that it's possible to "derate" a subpanel by using a smaller wire that can't carry the full capacity of the subpanel -- as long as you use a smaller breaker to feed the smaller wire and thus protect it from overheating. If it's a 50A or 75A or 100A subpanel, you might be able to upgrade the capacity of the existing panel by just changing out the wire and the breaker.
 

Sophias_dad

Active Member
Supporting Member
Jul 29, 2018
2,579
3,012
Massachusetts
What's the capacity of the subpanel? Note that it's possible to "derate" a subpanel by using a smaller wire that can't carry the full capacity of the subpanel -- as long as you use a smaller breaker to feed the smaller wire and thus protect it from overheating. If it's a 50A or 75A or 100A subpanel, you might be able to upgrade the capacity of the existing panel by just changing out the wire and the breaker.
That subpanel is rated to carry 100A.
 

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