Electric install questions

[alxla]

Hello,

I am new to Tesla and ordered a M3 performance.

I am going to install a plug in my garage (instead of a Wall charger).
It will be run to the main panel so I have flexibility to decide what to use.

What size of cable: #6 or else should I use?
What number of Amps: 50 or 60?
Also what type of plug if I want to maximize charging time speed and use the mobile connector?

Thanks!

 

[jjrandorin]

If you are going to install a plug instead of hard wiring a wall connector, you probably are planning on using the mobile connector that comes with the car. If all thats true, that maxes out at 32amps charging speed no matter which model 3 you have.

You will need a 40 amp circuit to charge at 32 amps. People tend to put in a 14-50 or 6 - 50 plug, with a 50 amp breaker, but that also will only charge at 32 amps if you use the mobile connector that comes with the car. I will let someone else more versed in the actual code requirements talk about the cabling.

 

[EVEnergy]

I did the same as you but to give myself some flexibility in the future (in case I want to buy the HPC later) I used #6 and a 60 amp breaker.

 

[Rocky_H]

First off, here:

Tesla Model 3/Y Home Charging Guide – TeslaTap

teslatap.com

That will give you an easy to read explanation of what you might want or need and why.

What size of cable: #6 or else should I use?
What number of Amps: 50 or 60?

These questions are kind of in the reverse order, but here is more of a general order of questions to go through:

1. First, you need to find out how much spare capacity you have. If you have a really big electrical service, maybe that's not an issue, but what would be done is called a "load calculation" to total up what your usage is versus your total electrical service.

2. Once you know how many amps you have available, then figure out what size circuit you want, and if that will fit in the spare capacity you have.

3. Location of the circuit. Is it going inside walls or in crawlspaces or attics or along the surfaces of walls in conduit or what? This will determine what type of wire or cable you would use.

4. Then, with knowing the number of amps of the circuit and what type of wire or cable, it's easy to look up in amp rating tables, which thickness (gauge) you have to use.

And in all this, there is a fundamental rule where there is the rated circuit size, and then the constant current draw can only be 80% of that. So for 60A circuits, 48A. For 40A circuits, 32A, etc.

 

[alxla]

First off, here:

Tesla Model 3/Y Home Charging Guide – TeslaTap

teslatap.com

That will give you an easy to read explanation of what you might want or need and why.


These questions are kind of in the reverse order, but here is more of a general order of questions to go through:

1. First, you need to find out how much spare capacity you have. If you have a really big electrical service, maybe that's not an issue, but what would be done is called a "load calculation" to total up what your usage is versus your total electrical service.

2. Once you know how many amps you have available, then figure out what size circuit you want, and if that will fit in the spare capacity you have.

3. Location of the circuit. Is it going inside walls or in crawlspaces or attics or along the surfaces of walls in conduit or what? This will determine what type of wire or cable you would use.

4. Then, with knowing the number of amps of the circuit and what type of wire or cable, it's easy to look up in amp rating tables, which thickness (gauge) you have to use.

And in all this, there is a fundamental rule where there is the rated circuit size, and then the constant current draw can only be 80% of that. So for 60A circuits, 48A. For 40A circuits, 32A, etc.

I should have said, I have capacity on panel and a conduit so I can run amp and cable size I want.

If I go for 60 amps and #6, will it work well with corded mobile connector?

 

[alxla]

If you are going to install a plug instead of hard wiring a wall connector, you probably are planning on using the mobile connector that comes with the car. If all thats true, that maxes out at 32amps charging speed no matter which model 3 you have.

You will need a 40 amp circuit to charge at 32 amps. People tend to put in a 14-50 or 6 - 50 plug, with a 50 amp breaker, but that also will only charge at 32 amps if you use the mobile connector that comes with the car. I will let someone else more versed in the actual code requirements talk about the cabling.

I realized that but because I am running new cable and adding breaker to the panel, I will rather do something that is future proof. My question is:
is it ok to do 60 amps and #6 with a 15-50 plug and a corded mobile connector?

 

[alxla]

I did the same as you but to give myself some flexibility in the future (in case I want to buy the HPC later) I used #6 and a 60 amp breaker.

HPC?

 

[jjrandorin]

HPC?

Thats most likely an abbreviation for "HPWC" or "high Power wall connector", which is name for the tesla wall connector (the "charger" is in the car). What gauge of cable depends on what type of cable and whether you are running it in conduit, etc.

Doing a quick google, I found this website, which says between 4 and 6 gauge:

What Size Wire for a 60 amp Breaker? - A Simple Explanation

Knowing what size wire for a 60 amp breaker is critically important. Check this article out for more information.

www.galvinpower.org

 

[Frank99]

If I go for 60 amps and #6, will it work well with corded mobile connector?

The standard outlet to use is either a 14-50 or a 6-50. Both of these are rated for 50A, so that’s generally the size circuit breaker you should use. #6 wire is good; it would allow you to upgrade to a wall mounted charger in the future, upgrade the circuit breaker to 60A, and charge a bit faster.
Yes, your solution is good. However, unless you know what you’re doing I strongly advise hiring an electrician and getting permits pulled/inspections done rather than attempting it yourself. You don’t want to turn yourself or your house into crispy critters.

 

[alxla]

I did the same as you but to give myself some flexibility in the future (in case I want to buy the HPC later) I used #6 and a 60 amp breaker.

What is the HPC?

 

[alxla]

Thats most likely an abbreviation for "HPWC" or "high Power wall connector", which is name for the tesla wall connector (the "charger" is in the car). What gauge of cable depends on what type of cable and whether you are running it in conduit, etc.

Doing a quick google, I found this website, which says between 4 and 6 gauge:

What Size Wire for a 60 amp Breaker? - A Simple Explanation

Knowing what size wire for a 60 amp breaker is critically important. Check this article out for more information.

www.galvinpower.org

Ok thanks! yes may be later so #6 cable looks good

 

[alxla]

The standard outlet to use is either a 14-50 or a 6-50. Both of these are rated for 50A, so that’s generally the size circuit breaker you should use. #6 wire is good; it would allow you to upgrade to a wall mounted charger in the future, upgrade the circuit breaker to 60A, and charge a bit faster.
Yes, your solution is good. However, unless you know what you’re doing I strongly advise hiring an electrician and getting permits pulled/inspections done rather than attempting it yourself. You don’t want to turn yourself or your house into crispy critters.

Yes thanks! an electrician will do it

 

[Sophias_dad]

So, all the answers above are correct, but you shouldn't consider using a 60 amp breaker on a 14-50 outlet even if the wiring should support it. A 60 amp breaker is only $10-20, and if you use that initially you'll have a (tiny) fire hazard, since your 14-50 outlet is only rated to move 50 amps. (Yes, I know it will only be moving 32 amps while you are using the UMC, but that doesn't mean the next person to own your home won't stick a kiln in the garage with the wrong cord on it and have the kiln ask for 60 amps because... you know.... there's a 60 amp breaker in there, it must be safe.

Also, don't forget the breaker for a 14-50 outlet needs to be GFCI, and will cost $100-$200.

 

[LoudMusic]

I would install a NEMA 14-50 outlet with all the associated standard cabling and breaker. Treat it as if it's a standard 240V50A outlet. Then plug your Tesla into it.

 

[alxla]

Thanks all for the answers!

 

[alxla]

Ok thanks! yes may be later so #6 cable looks good

Actually reading this again, it is ok to do #4 on 50 amps with 14-50 to be more bullet proof?

 

[bruce4000]

I would install a NEMA 14-50 outlet with all the associated standard cabling and breaker. Treat it as if it's a standard 240V50A outlet. Then plug your Tesla into it.

I agree. Also remember that the circuit breaker is to protect the house so should not be larger than what the wiring and outlet is rated for. Another question is how fast do you really need to charge every night? In my case I am retired and can get by with a standard 120v/ 15 amp circuit ( charging at 12amp derated for continuous) and get about 3mi/ hr or 1% per hour.

 

[Sophias_dad]

d.

Actually reading this again, it is ok to do #4 on 50 amps with 14-50 to be more bullet proof?

Yes it is. I also just checked the HBL9450A outlet, and it will take #12 through #4 conductors. That is itself a little strange, because to get the minimum-installable-ampacity(40A) for that outlet, you'd pretty much HAVE to use #8 or better.

Make sure you or your electrician uses a quality outlet. Leviton will NOT do the job. Hubbell/Bryant, and Cooper are all considerably better.

 

[Gauss Guzzler]

#4 wire will be difficult to cram into the outlet box and could cause more problems than it cures.

Also as @Sophias_dad noted, you'll want a decent ($40) outlet and a ($125) GFCI breaker (50A max). You'll also need a outlet cover and cord hook which adds another $30, and finally there's the $45 14-50 pigtail.

The wall charger doesn't need any of those things and it lets you keep the portable charger in the car for Airbnb's and stuff. It's also easy to connect the wall charger to #4 wire - no buckling/shoving required. So consider spending the extra $250 for the wall charger and note that the 30% tax credit means that it's actually only costing $175 more.

And when you upgrade in the future you can easily recoup your $175 cost by selling the old wall charger for $300.

Lastly, while there's almost no benefit to being able to charge faster than 32A (overnight is overnight), being able to charge 50% faster (48A) is huge if you forget or have visitors.

 

[alxla]

#4 wire will be difficult to cram into the outlet box and could cause more problems than it cures.

Also as @Sophias_dad noted, you'll want a decent ($40) outlet and a ($125) GFCI breaker (50A max). You'll also need a outlet cover and cord hook which adds another $30, and finally there's the $45 14-50 pigtail.

The wall charger doesn't need any of those things and it lets you keep the portable charger in the car for Airbnb's and stuff. It's also easy to connect the wall charger to #4 wire - no buckling/shoving required. So consider spending the extra $250 for the wall charger and note that the 30% tax credit means that it's actually only costing $175 more.

And when you upgrade in the future you can easily recoup your $175 cost by selling the old wall charger for $300.

Lastly, while there's almost no benefit to being able to charge faster than 32A (overnight is overnight), being able to charge 50% faster (48A) is huge if you forget or have visitors.

This is great info .. makes me reconsider my choice .. going to think about it further.
What is the cord hook?