Wiring for Wall Connector

[flixden]

Electrician says 6 gauge copper NM-B, 6/2 Romex with ground. This:

Southwire 50 ft. 6/2 Stranded Romex SIMpull CU NM-B W/G Wire 28894422 - The Home Depot

The Romex Type NM-B Copper Building Wire, featuring a patented SIMpull Cable Jacket, offers a hassle-free experience during installation, pulling, and stripping. Primarily intended for residential building

www.homedepot.com

Is that what everybody else is using?
Thanks!

 

[howardnj]

Electrician says 6 gauge copper NM-B, 6/2 Romex with ground. This:

Southwire 50 ft. 6/2 Stranded Romex SIMpull CU NM-B W/G Wire 28894422 - The Home Depot

The Romex Type NM-B Copper Building Wire, featuring a patented SIMpull Cable Jacket, offers a hassle-free experience during installation, pulling, and stripping. Primarily intended for residential building

www.homedepot.com

Is that what everybody else is using?
Thanks!

No!
What does your local code require? If your electrician is not licensed, perhaps you should find another one that is?
If a permit is required, your licensed electrician should be applying for one and arranging for the inspection.

 

[ATPMSD]

That is NOT acceptable if you plan to run the Wall Connector at the 48-amp charging speed. #6 Romex is rated at 55-amps, the wire needed must be rated at 60-amps.

Why? Because of the 80% rule. For a continuous load, which the connector is, you can draw only 80% of the wire’s rating. At 55-amps this equals 44-amps which is too low if you plan to run the connector at the top speed. A wire rated at 60-amps allows a draw 48-amps, which is what you need.

 

[h2ofun]

Electrician says 6 gauge copper NM-B, 6/2 Romex with ground. This:

Southwire 50 ft. 6/2 Stranded Romex SIMpull CU NM-B W/G Wire 28894422 - The Home Depot

The Romex Type NM-B Copper Building Wire, featuring a patented SIMpull Cable Jacket, offers a hassle-free experience during installation, pulling, and stripping. Primarily intended for residential building

www.homedepot.com

Is that what everybody else is using?
Thanks!

NO, NO, NO, hire a different electrician that knows the code
NM 6/2 only good for 55 amps

 

[flixden]

So that would be good for a 50A breaker then, and charging at 40A.
But what kind of wire should be used then for the full 60A (48A) charging?

 

[flixden]

6/2 MC, and this wouldn't need additional conduit, right? Like this?
Wirenco 6/2 Metal Clad (MC) Cable with Ground, Aluminum Armored, Stranded Copper Conductor (50Ft Cut) Amazon.com

 

[jcanoe]

6/2 MC, and this wouldn't need additional conduit, right? Like this?
Wirenco 6/2 Metal Clad (MC) Cable with Ground, Aluminum Armored, Stranded Copper Conductor (50Ft Cut) Amazon.com

Metallic clad (MC) wire can only be used indoors, in dry conditions. MC cannot be used outdoors, or underground or in a damp environment or crawl space. MC is commonly used in commercial wiring (inside walls). In homes MC is sometimes used in unfinished basements, attics and dry crawl spaces (where allowed.) Depending on local codes MC can be used in an enclosed garage (a garage with a garage door, enclosed on the other 3 sides is generally considered an indoor application.)

6/2 MC wire when used in residential applications is rated for 75C at up to 65 amps. (The 90C rating for MC is for commercial applications, not residential.)

 

[flixden]

Thanks much!
This would be in an enclosed garage, so the 6/2 MC should be fine, not even needing additional conduit if using something like what I linked above, correct?

Does anybody know why the rating is so different between the MC vs Romex? Looks like voth are stranded copper.

Are there any other 6 gauge options?

 

[jcanoe]

For my 240V, 50 amp circuit terminating with a 14-50 receptacle the electrician installed 8/3 MC. (The distance was ~70 feet from the panel to the garage location of the 14-50.) 8 gauge MC, at 75C, supports a maximum of 50 amps.

The difference in rating is due to the way NM-B is manufactured. NM-B wires are tightly bundled together. No air circulates around and between the individual conductors as with MC or individual wires in conduit.

 

[ewoodrick]

I'd personally go with 6/3 , it allows for more flexibility if you need to do something else.

 

[ATPMSD]

You can also use #6 THW/THWN, but this requires a conduit.

Cerrowire Resources - Ampacity Charts

Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.

www.cerrowire.com

As I understand MC, this is just the casing and what matters is the wire size and type inside. (?) Here is a page that shows the MC can and can’t do usages:

Wiring With MC – WHAT YOU CAN AND CAN’T DO WITH MC CABLE – Electrician U – Training for Electricians, by Electricians

electricianu.com

 

[sleepydoc]

Thanks much!
This would be in an enclosed garage, so the 6/2 MC should be fine, not even needing additional conduit if using something like what I linked above, correct?

Does anybody know why the rating is so different between the MC vs Romex? Looks like voth are stranded copper.

Are there any other 6 gauge options?

Wire size is just one factor. The ratings have to do with the wire material, the size of the wire, the type of insulation and the installation enclosure.

 

[ewoodrick]

I'd personally go with 6/3 , it allows for more flexibility if you need to do something else.

Actually I meant X/3. Whatever is the right gauge, but both hot legs and neutral. It's a lot more flexible when looking at other things that can be plugged in, like welders or travel trailers.

 

[Chewy13]

Wow, glad I decided to check this thread. Had a licensed electrician do my install, and had him pull a permit for my Wall connector.
Used the Romex 6-2 and wired it to a 60A breaker. Only reason I knew that was because I checked the jacket he threw in the trash to see what he used. Damn.
I just jumped into the web interface of the charger and changed it to 50A service…

 

[sleepydoc]

Wow, glad I decided to check this thread. Had a licensed electrician do my install, and had him pull a permit for my Wall connector.
Used the Romex 6-2 and wired it to a 60A breaker. Only reason I knew that was because I checked the jacket he threw in the trash to see what he used. Damn.
I just jumped into the web interface of the charger and changed it to 50A service…

It’s pretty trivial to swap out the 60A breaker for a 50A and as a practical matter you will probably never miss the extra charging speed. The big issue is you paid a licensed electrician and s/he did an improper job, giving you less than you paid for.

 

[Cosmacelf]

Thanks much!
This would be in an enclosed garage, so the 6/2 MC should be fine, not even needing additional conduit if using something like what I linked above, correct?

Does anybody know why the rating is so different between the MC vs Romex? Looks like voth are stranded copper.

Are there any other 6 gauge options?

Yes, I like MC cable for non wet conditions (like yours). No additional coduit required. Romex is de rated because it has a vinyl outer covering which can’t withstand 90 degrees C temps. MC being made of aluminum can, of course. Both cable types have the identical 6 gauge THHN wire inside.

Other 6 gauge options are pulling 6 gauge THHN wiring inside a metal or PVC conduit. You’d do this for wet conditions (metal conduit can be weatherproof if you use the appropriate fittings/connectors).

More info: CarCharging.us

 

[Cosmacelf]

The difference in rating is due to the way NM-B is manufactured. NM-B wires are tightly bundled together. No air circulates around and between the individual conductors as with MC or individual wires in conduit.

Nah, the reason is that NM-B outer covering melts at higher temperatures, so an attic install, hot summer months, where the attic air temps can get to 55 degrees C, add on top thermal heating from a high load, and the wire could be jammed Into a wood rafter along with a couple of other wires, means they have to de rate the cable. MC cable has exactly the same inner construction with same gauge THHN, but the outer jacket, made of aluminum, cant melt unless your whole house is already an inferno.

 

[Chewy13]

Nah, the reason is that NM-B outer covering melts at higher temperatures, so an attic install, hot summer months, where the attic air temps can get to 55 degrees C, add on top thermal heating from a high load, and the wire could be jammed Into a wood rafter along with a couple of other wires, means they have to de rate the cable. MC cable has exactly the same inner construction with same gauge THHN, but the outer jacket, made of aluminum, cant melt unless your whole house is already an inferno.

So that's interesting. My NM-B run is 27', through an insulated utility closet. Wall Connector is inside an enclosed garage that's adjacent to the utility room. If the conductors are the same, and it's the vinyl jacket temp rating which is the cause for the 55A rating - then I should be good to go @ 60A considering my installation conditions?

 

[ATPMSD]

It’s pretty trivial to swap out the 60A breaker for a 50A and as a practical matter you will probably never miss the extra charging speed. The big issue is you paid a licensed electrician and s/he did an improper job, giving you less than you paid for.

Unfortunately this is a common error, but what is worse is that this is not even acceptable for an “intermittent” 60A load as it violates the “round-up” rule for intermittent loads.

 

[ATPMSD]

So that's interesting. My NM-B run is 27', through an insulated utility closet. Wall Connector is inside an enclosed garage that's adjacent to the utility room. If the conductors are the same, and it's the vinyl jacket temp rating which is the cause for the 55A rating - then I should be good to go @ 60A considering my installation conditions?

You cannot use #6 NM-B in a 60A circuit, please read post #3. You must set your wall connector as being on a 50A circuit and you should use a 50A breaker.