4/3 MC Cable for the Charger

[rajesh G]

Hi,

I am planning to install the Tesla home charger and to get max output thinking of using 4/3 MC without conduit. Is it OK to use the cable from the below link?
I am planning to run from unfinished basement to the garage(50 feet), so there will be a place(~10 feet), where it will run between the insulation and Drywall. Do i need a conduit?

4/3 Metal Clad (MC) Cable with Ground, Aluminum Armored, Stranded Copp

Applications:Branch, feeder or service power distribution in commercial, industrial, institutional and multi-residential buildings. Lighting, power, control and signal circuits. Fished or embedded in plaster, concealed or exposed installations. Environmental air handling spaces per NEC 300.22...

shopwirenco.com

Thanks,
rg

 

[terranx]

You can run MC cable exposed and without conduit. But you'd be fine with 6/3 (good for 65A). Or 6/2 even. I had bought the cable for my install from the above vendor. No issues.

 

[ATPMSD]

You can run MC cable exposed and without conduit. But you'd be fine with 6/3 (good for 65A). Or 6/2 even. I had bought the cable for my install from the above vendor. No issues.

Pretty sure (?) 6/3 or 6/2 MC is limited to 55-amps in a home so it cannot be used for a wall connector if you want to get the full 48-amps out of the wall connector as it needs wire rated at 60-amps. And the problem with #4 wire is the maximum size wire for the connection to the wall connector terminals is #6, so you will need address that using a bridge with something like #6 THWN.

 

[terranx]

Pretty sure (?) 6/3 or 6/2 MC is limited to 55-amps in a home so it cannot be used for a wall connector if you want to get the full 48-amps out of the wall connector as it needs wire rated at 60-amps. And the problem with #4 wire is the maximum size wire for the connection to the wall connector terminals is #6, so you will need address that using a bridge with something like #6 THWN.

Incorrect. 6 awg mc cable is good for 65A (technically even 75 A if you’re able to use the 90C ratings)

 

[ATPMSD]

Incorrect. 6 awg mc cable is good for 65A (technically even 75 A if you’re able to use the 90C ratings)

See this link, home wire is usually limited to 60C just like NM-B, isn’t it?

http://www.cmewire.com/catalog/sec01-bwx/bwx-03-mc-amp.pdf

See also

Ampacity Calculator

The purpose of this calculator is to determine the ampacity of conductors in conduit, cable, or directly buried. All calculations are based on the National Electrical Code®.

www.cerrowire.com

 

[terranx]

See this link, home wire is usually limited to 60C just like NM-B, isn’t it?

http://www.cmewire.com/catalog/sec01-bwx/bwx-03-mc-amp.pdf

See also

Ampacity Calculator

The purpose of this calculator is to determine the ampacity of conductors in conduit, cable, or directly buried. All calculations are based on the National Electrical Code®.

www.cerrowire.com

No. Only nm-b is limited to 60c. Most others can go to 90, but it’s rare to have 90° rated terminals. 75 is fair game

 

[ATPMSD]

No. Only nm-b is limited to 60c. Most others can go to 90, but it’s rare to have 90° rated terminals. 75 is fair game

So it sounds like as long as the breaker and terminals are properly rated all is good. Thanks!

 

[Cosmacelf]

Hi,

I am planning to install the Tesla home charger and to get max output thinking of using 4/3 MC without conduit. Is it OK to use the cable from the below link?
I am planning to run from unfinished basement to the garage(50 feet), so there will be a place(~10 feet), where it will run between the insulation and Drywall. Do i need a conduit?

4/3 Metal Clad (MC) Cable with Ground, Aluminum Armored, Stranded Copp

Applications:Branch, feeder or service power distribution in commercial, industrial, institutional and multi-residential buildings. Lighting, power, control and signal circuits. Fished or embedded in plaster, concealed or exposed installations. Environmental air handling spaces per NEC 300.22...

shopwirenco.com

Thanks,
rg

For a 48A EVSE like the Tesla Wall Connector, all you need is 6/2 MC cable. See Advice for EV Charging in North America

 

[rajesh G]

You can run MC cable exposed and without conduit. But you'd be fine with 6/3 (good for 65A). Or 6/2 even. I had bought the cable for my install from the above vendor. No issues.

Thank you for the input …i will go with 6/2 and also makes me comfortable that u bought from the vendor.

 

[rajesh G]

For a 48A EVSE like the Tesla Wall Connector, all you need is 6/2 MC cable. See Advice for EV Charging in North America

Thank you ….very informative article for a newbie.

 

[rajesh G]

Pretty sure (?) 6/3 or 6/2 MC is limited to 55-amps in a home so it cannot be used for a wall connector if you want to get the full 48-amps out of the wall connector as it needs wire rated at 60-amps. And the problem with #4 wire is the maximum size wire for the connection to the wall connector terminals is #6, so you will need address that using a bridge with something like #6 THWN.

Thanks for the reply ….Just curious why we need a Bridge ?

 

[rajesh G]

You can run MC cable exposed and without conduit. But you'd be fine with 6/3 (good for 65A). Or 6/2 even. I had bought the cable for my install from the above vendor. No issues.

Any protocols to follow when using MC cable…especially when pulling the cable into the tesla terminal?

 

[terranx]

Any protocols to follow when using MC cable…especially when pulling the cable into the tesla terminal?

Not really. MC cable is effectively THHN wire preinstalled in flexible conduit. Just make sure you're using the right bushings and that sort of thing. Notably the 1/2" size is the appropriate size even though the diameter of the cable is about 3/4".

 

[ATPMSD]

Thanks for the reply ….Just curious why we need a Bridge ?

Unless this has changed (I went looking for the source but cannot find it, so perhaps this is no longer applicable), the connections in the wall connector are sized for a maximum of #6 wire, so #4 wire will be too large. Thus, you would need to use a bridge in which you connect #4 wire to one side and #6 to the side going to the wall connector. This is moot, of course, as you plan to use #6 wire.

 

[Tropical Jack]

The wall connector I installed at my house 4 months ago could utilize #4 ( and I did). I used 1” PVC conduit and THHN wire.

 

[terranx]

Unless this has changed (I went looking for the source but cannot find it, so perhaps this is no longer applicable), the connections in the wall connector are sized for a maximum of #6 wire, so #4 wire will be too large. Thus, you would need to use a bridge in which you connect #4 wire to one side and #6 to the side going to the wall connector. This is moot, of course, as you plan to use #6 wire.

Manual says it can take 4 awg wire

 

[ATPMSD]

Manual says it can take 4 awg wire

Great! No such specs in my manual, which must now be out of date. Thanks.

 

[terranx]

Page 7 here: https://www.tesla.com/sites/default...ng/Gen3_WallConnector_Installation_Manual.pdf

 

[howardnj]

Hi,

I am planning to install the Tesla home charger and to get max output thinking of using 4/3 MC without conduit. Is it OK to use the cable from the below link?
I am planning to run from unfinished basement to the garage(50 feet), so there will be a place(~10 feet), where it will run between the insulation and Drywall. Do i need a conduit?

4/3 Metal Clad (MC) Cable with Ground, Aluminum Armored, Stranded Copp

Applications:Branch, feeder or service power distribution in commercial, industrial, institutional and multi-residential buildings. Lighting, power, control and signal circuits. Fished or embedded in plaster, concealed or exposed installations. Environmental air handling spaces per NEC 300.22...

shopwirenco.com

Thanks,
rg

Use a licensed electrician from your state that will apply for a permit and inspection.
Installing a wall charger that draws 48 amps is a device improperly installed can start a fire, burn down your house, and provide an out for your insurance company not to pay. I'm just sayin

 

[rajesh G]

Use a licensed electrician from your state that will apply for a permit and inspection.
Installing a wall charger that draws 48 amps is a device improperly installed can start a fire, burn down your house, and provide an out for your insurance company not to pay. I'm just sayin

Sure!!! I am not planning to install myself, Just buying the material and will be using a Licensed electrician.