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Discussion Starter · #1 ·
Hi, I wanted to install NEMA 14-50 receptacle in my garage for EV charging. Planning 40amp circuit. 40amp breaker, 8/3 wire (about 50 feet needed). My panel is in basement. Planning to get ESA permit myself (as home owner). My location is Ontario. Attached the image of the panel.

1. My panel is 100amp, I have AC, electric dryer and stove. The receptacle is for EV charging, it pull continuously 32 amp when charger connected. I don't think I will use all these - AC, stove and dryer at same time and only plan to charge EV at night most of the time. Can I manage with 100 amp panel? Any electrical code issue that I should aware in this case?

2. Do I need a GFCI/AFCI breaker for this circuit? what is the code in Ontario/ESA?

3. Most of the area in the basement where wire goes is unfinished however close to panel it is finished area so I am planning to fish wire there (easy), would this finished area be a problem for inspection? do I need to cut open the drywall in that case for inspector to see wire?

Thanks in advance!

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No, the drywall does not have to be cut open.to inspect the wiring that was installed using approved and customary methods.
 
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The receptacle is for EV charging, it pull continuously 32 amp when charger connected.
Because that is 80% of 40A. Continuous loads (and plug-in loads) are required to limit to 80% of circuit ampacity.

I'm not going to be mad at you for not understanding this, because this is really new technology. But.

That lump in the cord / thing on the wall is called EVSE (Electric Vehicle Supply Equipment) is not the charger. That's in the car. The EVSE's job is to tell the EV "The port you're plugged into has 24A available" (e.g. because it's a 30A circuit). The EV then draws 24A and no more. Plug in using the 120V dongle, then it will say "The port you're plugged into has 12A available". Etc.

Your car also has a hard max: if you plugged into a 100A EVSE and the EVSE said "You have 80A available" your car will draw 32A because that's its personal max.

A NEMA 14-50 socket is advertising that it has netural available (EVs don't use that)... and it has 50A available. The car you have today happens to have a max of 32A, but what about your next car? Visitor car? You sell the house?



Hi, I wanted to install NEMA 14-50 receptacle in my garage for EV charging. Planning 40amp circuit. 40amp breaker, 8/3 wire (about 50 feet needed). My panel is in basement. Planning to get ESA permit myself (as home owner). My location is Ontario. Attached the image of the panel.
DO NOT run a 40A circuit to a NEMA 14-50 receptacle for EV charging. The 14-50 is advertising that it has 50A available not 40A. Most EVSE's will pull current like it's a 50A circuit (meaning pulling 40A continuously, and the breaker will probably tolerate this). Maybe this particular car doesn't, but you'll get a new model in a few years right?

In fact, I don't want to overload you with info, but the NEMA 14-50 is a source of high stupidity. A lot of people get fixated on it, because the car "comes with" a small "travel charger" meant for opportunity charging on the road. The travel charger comes with a normal 120V plug and a NEMA 14-50 - why? Because, NEMA 14-50 is found at RV campgrounds and sites. They are not recommending NEMA 14-50 as an EV charge socket at home. In fact they sell alternate plug dongles for a huge variety of sockets.

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All these are for sale, consult your manufacturer. The dongle has a micro-chip molded into the plug, that tells the car 15A, 20A, 30A or 50A. Per Code, it also monitors plug temperature and reduces or shuts off charge if the plug is getting hot.


In fact, Code requires you do a Load Calculation to determine the spare ampacity your home can dedicate to EV charging. By installing a 14-50 you are just presuming that number is 50 amps. It might be 30A, 20A or even 15A. You need to crunch those numbers.

Once you identify the ampacity, you pick the next smaller size out of 15, 20, 30 or 50. For you this is unlikely to be 50, so you'll be changing socket amps anyway and thus buy a different dongle... so you might as well seize the opportunity and go with a 3-wire cable and socket, and save some money on your wire.

If you install a 14-30 or -50 you MUST install the neutral wire from the panel (because someone might plug an RV into that, and a missing neutral will fry most things that require 14-50). However the EV doesn't actually use the neutral.


1. My panel is 100amp, I have AC, electric dryer and stove. I don't think I will use all these - AC, stove and dryer at same time and only plan to charge EV at night most of the time. Can I manage with 100 amp panel? Any electrical code issue that I should aware in this case?
That gets sorted out in the Load Calculation. "No frickin' way" is my sense, but crunch the numbers for yourself.

There's a technology on the verge (available now for C$7000, will come down dramatically soon) which I call "Demand side management" but will probably be called "smart panels". This can schedule large loads so they don't combine to overload the panel. A readily available, but very "ghetto" option is to use a $30 Generator Interlock to lock out 2 of your loads so only one can be on at the same time. E.G. dryer and EVSE. Then, the smaller of the two loads simply disappears from your Load Calculation. The side-by-side interlocks even allow an interlock on each side of the EVSE breaker, which means it could be interlocked with two other loads (dryer and range?)

2. Do I need a GFCI/AFCI breaker for this circuit? what is the code in Ontario/ESA?
I don't think so yet, but meet the other stupidity of plug-and-socket connected EVSEs.

EVSE's actually have a second job, which is to be a GFCI to protect the car. They are smart GFCIs which will automatically "self-reset" several times to see if the fault cleared. If they have WiFi etc. capability, they will tell you if they can't.

This means hardwired EVSEs (think: wall-mount units) will never need GFCI protection. Don't need a GFCI on a GFCI.

However, when an EVSE is connected plug/socket, the installer isn't installing an EVSE. They're installing a socket anything could be plugged into. Thus, they must comply with then-relevant local rules on GFCI.

3. Most of the area in the basement where wire goes is unfinished however close to panel it is finished area so I am planning to fish wire there (easy), would this finished area be a problem for inspection? do I need to cut open the drywall in that case for inspector to see wire?
No, they're not going to make you do that. Hey, did you know Canada has an amazing cable type called TECK? It was developed for mines, but apparently is widely used and solves many problems. It might even be allowed 75C thermal, granting 50A on #8 wire.
 

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Discussion Starter · #5 · (Edited)
Firstly, Thank you for your detailed reply. really appreciate it.

That lump in the cord / thing on the wall is called EVSE (Electric Vehicle Supply Equipment) is not the charger. That's in the car. The EVSE's job is to tell the EV "The port you're plugged into has 24A available" (e.g. because it's a 30A circuit). The EV then draws 24A and no more. Plug in using the 120V dongle, then it will say "The port you're plugged into has 12A available". Etc.

Your car also has a hard max: if you plugged into a 100A EVSE and the EVSE said "You have 80A available" your car will draw 32A because that's its personal max.

A NEMA 14-50 socket is advertising that it has netural available (EVs don't use that)... and it has 50A available. The car you have today happens to have a max of 32A, but what about your next car? Visitor car? You sell the house?
yes I understand it. charger is in the car. Few things I should have mentioned. My car (Tesla model 3 LR) can draw up to 48amp (60 amp circuit) but I am limiting myself because, I will be moving out from this home after an year or so, 32amp overnight charge is plenty for me, reduction in cost - considering how prices of these material gone up (6/3 wire v/s 8/3 wire if I am using 40amp etc.), my panel is only 100amp, and I have the 14-50 adapter already. Yes it would have been more nice to use 6-50 as neutral wire is no use but I already have 14-50 adapter hence I am going this route.

DO NOT run a 40A circuit to a NEMA 14-50 receptacle for EV charging. The 14-50 is advertising that it has 50A available not 40A. Most EVSE's will pull current like it's a 50A circuit (meaning pulling 40A continuously, and the breaker will probably tolerate this). Maybe this particular car doesn't, but you'll get a new model in a few years right?
Understand what you are trying to say. May be I will write near receptacle 40amp is max. There is no 40amp receptacle so! Yes my car cord (mobile connector) only will pull 32 amp max. I have options to hard-wire (wall connector) or use another connector to pull up to 40amp max but I am not planning to do it with this house. But as you said if someone in the future connects a more amp breaker will trip, so this writing near receptacle to be clear.

In fact, I don't want to overload you with info, but the NEMA 14-50 is a source of high stupidity. A lot of people get fixated on it, because the car "comes with" a small "travel charger" meant for opportunity charging on the road. The travel charger comes with a normal 120V plug and a NEMA 14-50 - why? Because, NEMA 14-50 is found at RV campgrounds and sites. They are not recommending NEMA 14-50 as an EV charge socket at home. In fact they sell alternate plug dongles for a huge variety of sockets.
yes it all started from Tesla's suggestion on installing nema 14-5, as an alternate option to their wall connector and they have a document on this one. Since then I had done enough research, and the next best option can think of is nema 6-50.

Once you identify the ampacity, you pick the next smaller size out of 15, 20, 30 or 50. For you this is unlikely to be 50, so you'll be changing socket amps anyway and thus buy a different dongle... so you might as well seize the opportunity and go with a 3-wire cable and socket, and save some money on your wire.
yea I was considering this as well - further reduction in cost with nema 6-50 and 8/2 wire.

If you install a 14-30 or -50 you MUST install the neutral wire from the panel (because someone might plug an RV into that, and a missing neutral will fry most things that require 14-50). However the EV doesn't actually use the neutral.
yes I will be using 8/3 wire only. so have 2 hot, 1 neutral and 1 ground.


I don't think so yet, but meet the other stupidity of plug-and-socket connected EVSEs.
was trying to make sure based on electrical code here in Ontario.

Thanks again
 

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32amp overnight charge is plenty for me, reduction in cost - considering how prices of these material gone up (6/3 wire v/s 8/3 wire if I am using 40amp etc.),
Try other cable types. Basic NM is limited to 60C thermal so it's only 40A for #8 copper and 55A for #6.
#8 4-wire should be 50A if it's a cable type allowed 75C thermal.

Or since you are going to a socket, and most 50A sockets are rated for aluminum wire and 75C, so you can go 6-6-6-6 aluminum, that stuff is dirt cheap. That's 50A wire @ 75C.

The next size up of aluminum from a practical POV is #2 at 90A. It is a very common size so it's almost cheaper than #4. Keep that in mind for your next house. You can't run AL direct to a hardwired Tesla EVSE, but you need a disconnect for a hardwired EVSE anyway, and virtually all disconnects accept aluminum wire. Use copper for the last 6 feet to the EVSE. The best disconnect is a subpanel.

my panel is only 100amp, and I have the 14-50 adapter already.
The fact that you already have the dongle end and don't want to buy another, does not mean that your house can safely power that. Only a load calculation will tell. Like I say, generator interlocks can be used as a poor man's load shed if you must pre-empt one appliance to charge.
 

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Also, if you anticipate plugging and unplugging your mobile connector from a 14-50 receptacle, you should understand that there is a wide variation in quality and cheap could be dangerous.
 

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I installed one (outdoors) 4 years ago. Did my research. In the US.
My car draws 6600w, [email protected] (Nissan Leaf). The plug is a NEMA 14-50. You are not allowed to wire it for anything less that it's 50a rating. It's 4 prongs so you have to use 6/4 wire minimum, and a 50a circuit breaker. My wife is an insurance adjuster. Here in the States, if you wire your own stuff without a permit and there is a fire. The insurance company will deny your claim. It's written into the homeowner policy that you signed when you received coverage. Your family's safety is worth WAY more than the few bucks you'll save choosing inferior material.
Taken from the Tesla site. †Maximum charge rate for Model 3 Rear-Wheel Drive is 32A (7.7kW) - up to 30 miles of range per hour.
You can use one of those solar power calculators to estimate what your peak power usage is.
 

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Discussion Starter · #9 ·
Try other cable types. Basic NM is limited to 60C thermal so it's only 40A for #8 copper and 55A for #6.
The fact that you already have the dongle end and don't want to buy another, does not mean that your house can safely power that. Only a load calculation will tell. Like I say, generator interlocks can be used as a poor man's load shed if you must pre-empt one appliance to charge.
No, no. I was trying to avoid a panel upgrade if possible. what I meant is as I have 14-50 adapter already I would prefer to go that route - using a nema 14-50 if possible instead of another receptacle like - 6-50.
 

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Discussion Starter · #10 ·
I installed one (outdoors) 4 years ago. Did my research. In the US.
My car draws 6600w, [email protected] (Nissan Leaf). The plug is a NEMA 14-50. You are not allowed to wire it for anything less that it's 50a rating. It's 4 prongs so you have to use 6/4 wire minimum, and a 50a circuit breaker. My wife is an insurance adjuster. Here in the States, if you wire your own stuff without a permit and there is a fire. The insurance company will deny your claim. It's written into the homeowner policy that you signed when you received coverage. Your family's safety is worth WAY more than the few bucks you'll save choosing inferior material.
Taken from the Tesla site. †Maximum charge rate for Model 3 Rear-Wheel Drive is 32A (7.7kW) - up to 30 miles of range per hour.
You can use one of those solar power calculators to estimate what your peak power usage is.
we can connect a 40 amp circuit to nema-14-50. It is with in code (at least here in Canada), why? because there is no 40 amp receptacle or plug as per the NEMA standards. The only thing, as discussed above earlier, it might confuse someone in future and they may end-up connecting a 50 amp draw equipment and trip the breaker. Here in Canada we have most electric stove uses NEMA 14-50 and the circuit is 40 amp. That is the case in my home too, stove plug (14-50) is on a 40 amp circuit. Between it is straight from my house builder and passed all inspection/permit.

6/3 wire = #6 and 4 wire. That means 6/3 will have 3 conductors and 1 ground (total 4 wire) that's the right one for NEMA not the 6/4.

And yes I will pull a permit hence these thread and question before I call them. Usually I can ask these questions to them directly but thought to get some suggestions from here before I approach them to make it easy for me.

The Tesla max charge rate you have given is for RWD, mine LR (Long Range) and it has much more capability (11.5 kw/ 44 mph). I am owning it for 3 years and very clear on those :) I was able to manage with normal plug so far considering how less I drove last years due to covid and all. but at times it would have been helpful to have some faster charge rates. I can still manage with 110v plug but considering to upgrade.
 
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