Circuits are not intended to run continuously at more than 80% of rated amps. For a 40 amp circuit this is 32 amps.
Will the charger regularly draw 32 amps or more?
You also have to derate the wire for the higher temperature found in up near the roof.
So now what you thought was a 40 amp circuit becomes more like 30 amps or less.
This is important because fixed wiring causes about 70% of fires in residential structures.

An EVSE is not much more than a junction box with a disconnect in it and a pigtail or cord reel that plugs into the EV. The actual charging system is built into the vehicle. As such, it is useless to spend big bucks on a super duty EVSE if your vehicle will never draw full rated power.

I remember hearing that the early Leafs have a smallish charging system. They were upgraded in 2013 or 2014. I don't remember the exact figures, but I believe the older models only charge at 15 or 20 amps. I'm not sure if the high-cap charging is standard on the new models, but it is 30 amp.

Yes , I am aware of all of that . I have over 35 years in the trade .

I also know many fires that can not be determined as to cause , are blamed on electrical . Every one accepts that explanation , nods their heads and are satisfied . And down the road they go .

I think our 2012 Leaf has a 3.3 kw charger . When you do the math ( Ohm's Law ) that comes out to 13.75 amps at 240 VAC 1 phase . Continuous duty is 3 hours or more . Not sure if it takes 3 hours to charge , but throw that in and I get 17.1875 amps . And not sure if the charger starts to taper off when the battery approaches 100% ?

I think the 2016 Leaf has a 6.6 kw charger . So , that would be 34.375 amps . Still OK on # 8/2 W/G Romex and a 40 amp Circuit Breaker .

If , at some point I get a newer Leaf with the 6.6 kw charger , I will be OK .

And still OK if you derate the ampacity of the cable for elevated temperature .

The Chevy Bolt specs indicate a 7.2 kw charger . This gives a 30 amp draw at 240 VAC -> 37.5 amps . Might or might not have issues due to elevated temperatures . If I should ever buy a Bolt ?

But , I am pretty sure the GE Watt Station has the capability to change a jumper on the control board to step it down as far as output ?

Jumper J21

for 30A Circuit
Optional position C … connect other end of wire to position #4 and the DuraStation will provide a duty cycle to the car indicating that only 24A may be drawn. This position should be used when installing the DuraStation on a 30A branch circuit.

Or , I could use the # 8/2 W/G as a pull cable & pull a new # 6/2 W/G . I had the # 8/2 W/G on hand & it will be sufficient for the foreseeable future .

God bless
Wyr

I bought the EVSE capable of operating on a 40 amp Circuit Breaker , so I would be OK if I , at some time ended up with an EV that required that capacity .

Very little cost difference in the EVSE . Almost no cost difference in my cost to self install .

If I never need a 40 amp circuit , no harm done .

God bless
Wyr

13 amps, ha you could have wired that on a 12 gauge circuit.
So I take it you are planning on getting something with bigger charger at some point or charging 2 vehicles like this or you like to over wire?

I tend to over wire stuff too. The 240v circuits I wired in for welders, plasma cutters and air compressor are all sized for continuous duty.

You never can tell .

For me , it may turn out to be an expensive lark . Or I may fall head over heals for EV's .

As I said , it cost me very little more to go with an EVSE , wire & Circuit Breaker that support 40 amps .

God bless
Wyr

Bigger wire is more efficient due to smaller resistive losses. A couple of percent more energy ending up where it belongs translates to more miles per electric bill. You know the deal. The heavier than absolutely necessary wire pays you back over time.

I generally think of it in terms of voltage drop .

But , it also involves distance . But , in this case , the distance was not significant .

God bless
Wyr

I really like your Leaf. Congratulations!

I'm curious if the Leaf was always in your local area, and what kind of range does it have? Where I work (see profile), getting permission to plug-in is just not possible, ever. The used Leaf pricing I see around here is very attractive though.......

Evidently , Nissan sells the Leaf nation wide . Since I was looking at the used market , it was hit or miss . The next big towns around us tend to be around 2 hours away , give or take .

We looked at one SE of us & did not buy . Ended up buying one N of us . A few days ago I received an email that there is now a used Leaf , local .

Have I posted about the battery degrading with heat ?

If not & if you are interested , ask .

Brand new , they are suppose to be around 80 miles for the older ones w/ 24 kwh battery . Newest ones have a 30 something kwh battery & are said to have 100 mile range or a little more .

Mine shows around 73 miles on the GOM ( Guess O Meter ).

God bless
Wyr