Home L2 Charging: 40A versus 48A

Aye Aye Ron

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You really don’t need 4 gauge to run at 48 amps. 6 gauge is ok up to 65amps which you will not approach. The Mach e will only take 10.5kw on the level 2 charger. That means the max current it will take at 240v is 43.75amps.
Do be careful with this as there is a difference between copper and aluminum conductors but the biggest difference is in the temperature rating of the insulation that coats the wires.
You can install 'the correct' wire size but if the insulation is wrong you can be out of spec and under rated. Not good.
Look up 'Ampacity Chart' for more info.
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RickMachE

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You really don’t need 4 gauge to run at 48 amps. 6 gauge is ok up to 65amps which you will not approach. The Mach e will only take 10.5kw on the level 2 charger. That means the max current it will take at 240v is 43.75amps.
My JuiceBox 48 has shown 11.32kw.

As to the connection, the wires connect in a box on the wall, not in the unit.

Ford Mustang Mach-E Home L2 Charging: 40A versus 48A Screenshot_20220421-200436
 
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Moomin

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Check your local codes. I bought ChargePoint and had to hardwire it. My area requires the Nema outlet to have a GFCI breaker and since the Chrgr has an internal one, it has been causing many units to trip and you find out in the morning. Hardwire does not require gfci breaker.
 

RickMachE

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That's not the case with a hardwired ChargePoint Home Flex.
Interesting. You're right. JuiceBox uses a junction box, ChargePoint doesn't. Glad I got a JuiceBox. If I move, turn off breaker (and mark it), open junction box, disconnect wires.
 
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SWO

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I recently purchased a ChargePoint Home Flex with a NEMA 6-50 plug at list price. NEMA 14-50 model is out of stock in most places, delayed shipping and costing more.

Anyway, I'm torn between hardwire install with 240V/48A supply/60A Breaker (estimated range per hour of 36 miles) and plug-install with 240V/40A supply/50A Breaker (estimated range per hour of 30 miles). Would appreciate hearing from owners who have one of the 40A or 48A setups (doesn't have to be a ChargePoint EVSE) with their pros and cons. My chosen electrician has quoted $150 difference between hardwire and plug install; not enough to sway me one way or another; wire-run of 35 feet from breaker panel. I plan to carry the Ford-supplied EVSE w/cables in my frunk as I know the NEMA 14-50 plug is more prevalent across the country.

Thanks for any input you provide!
Ask your electrician to swap a 14-50 pigtail on your EVSE if you decide to go the 40A route.
 

JCHLi

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The difference is about 1.9 kW per hour. For me charging from 11pm until 6am, I have more than enough time to charge about 75% of my battery using 40 amps.

At 48 amps, is could charge about 90% in the same time.

(Obviously there are differences in voltages and some charging losses so this is just a rough estimate).

For me, it's about how much do I need to charge and how fast I need it. I don't need the 48 amps, so I like having an outlet I can use if I ever decide to weld again.
 

dbsb3233

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I recently purchased a ChargePoint Home Flex with a NEMA 6-50 plug at list price. NEMA 14-50 model is out of stock in most places, delayed shipping and costing more.

Anyway, I'm torn between hardwire install with 240V/48A supply/60A Breaker (estimated range per hour of 36 miles) and plug-install with 240V/40A supply/50A Breaker (estimated range per hour of 30 miles). Would appreciate hearing from owners who have one of the 40A or 48A setups (doesn't have to be a ChargePoint EVSE) with their pros and cons. My chosen electrician has quoted $150 difference between hardwire and plug install; not enough to sway me one way or another; wire-run of 35 feet from breaker panel. I plan to carry the Ford-supplied EVSE w/cables in my frunk as I know the NEMA 14-50 plug is more prevalent across the country.

Thanks for any input you provide!
Advantages of an outlet over a hardwire is easy swapability if the EVSE ever dies and you need a new one, or you want to test the included mobile charger once in a while, ever want to plug another 240V decice in the garage as some point (welder?), etc.

Downside of an outlet vs a hardwire is a slightly less dependable connection. The contacts can work loose if you plug/unplug a lot, and it tends to be the weak point in the connection (although still usually plenty safe).

Personally, I have a 14-50 Grizzl-E (40A max) on a 50A breaker, and I've dialed it down to just 24A. That's plenty fast for my situation. I don't have time-of-use rates and I don't need to leave early in the morning for work, so 24A always fills the battery overnight with no problem. Even though everything is rated to handle more power, more current always means more heat, which means faster gradual degradation of the equipment. Years of flexing those cables and connection points could quietly produce a weak spot. So as a general rule, I just like to run as little as needed through it just in case. And I can always bump it up to 32A or 40A if my situation changes and I need more.
 

KevinS

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Personally, I have a 14-50 Grizzl-E (40A max) on a 50A breaker, and I've dialed it down to just 24A. That's plenty fast for my situation. I don't have time-of-use rates and I don't need to leave early in the morning for work, so 24A always fills the battery overnight with no problem. Even though everything is rated to handle more power, more current always means more heat, which means faster gradual degradation of the equipment. Years of flexing those cables and connection points could quietly produce a weak spot. So as a general rule, I just like to run as little as needed through it just in case. And I can always bump it up to 32A or 40A if my situation changes and I need more.
Thank you for raising this point; I've actually done something similar with my ChargePoint charger on a 50A circuit (derated it in software from 50A to 40A)
 

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Do all level 2 chargers have to be hardwired? Or could they be used with 14-50 outlet on 50amp?
 

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Do all level 2 chargers have to be hardwired? Or could they be used with 14-50 outlet on 50amp?
The only ones that have to be hardwired are those over 40A, because a 14-50 outlet is rated at 50A max (which means no more than a 40A device plugged in (80% rule)). Any EVSE 40A or below can be either plug or hardwired.
 

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Instead of choosing between a hard-wired charger at 48 amps or installing a 14-50 outlet that puts out a max of 40amps, I recommend you get both. That is what I had done. In my case, it only cost about $450 extra. That way 1) you are able to charge at 48 amps if and when needed (although to be honest, I have not found this to be necessary all that often) 2) If there is a problem with your hard-wired charger, you can still charge using the 14-50 outlet and your mobile charger (or you can quickly and easily install a 40-amp plug-in charger).

When I first got my Tesla, my Tesla Wall Connector had to be replaced (under warranty) but it still took 4 weeks from the time I contacted Tesla and the time my new Wall Connector was installed. During those 4 weeks, I had to make due with public level 2 chargers. It would have been very helpful to have a 14-50 outlet as a backup.

And don't forget to check with your local utility for any rebates. My local power company offers a $500 rebate but only for hard-wired chargers. So if the same is true for you, this could be a big deciding factor.
 

ARK

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I would hardwire it on the appropriate 60A circuit and then tell the unit it is on a 40A breaker so it charges at 32A. Less thermal issues at 32A..
I agree with this, I would go with the 60amp circuit for future proofing, and for occasions where you might unexpectedly need a faster charge. But otherwise agree that for normal, overnight charging you want to derate it and charge at a lower rate for long-term battery health. This is very easy to adjust through the ChargePoint app.

I also charge at 32 amps overnight, makes no difference to me if the charge is done at 3:00 a.m. instead of 1:00 a.m. sort of thing.
 

Maquis

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You really don’t need 4 gauge to run at 48 amps. 6 gauge is ok up to 65amps which you will not approach. The Mach e will only take 10.5kw on the level 2 charger. That means the max current it will take at 240v is 43.75amps.
That’s only true for pipe and wire. #6 NM cable is limited to 55A.
 

dbsb3233

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Another potential factor for whether you feel the need to go with what's usually overkill (60A) "just in case" is whether you have any public DCFC nearby that you can always just go fast charge in a rare high need situation. Home charging on L2 is far better 99% of the time, of course, but if you only have a handful of times per year you might need a faster charge, a nearby DCFC is another option without going overkill at home.

On the other hand, BEVs in the future are likely to have bigger batteries, especially on SUVs and trucks. I expect 120-150 kWh batteries to be pretty common on larger EVs. The F-150 Lightning's large battery is 131 kWh usable. The future Explorer EV will probably be similar.

Then there's the consideration for a possible dual charger in the future if you think you might ever have 2 BEVs at once.
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