[CommodoreAmiga]

Hmmm, OK, so if the electrician installed the wiring back to the fuse panel that is at least 6 gauge wire, it should be do-able right? After all the wiring is rated correctly, just need the circuit breakers updated, right?

Are you asking if you can keep the NEMA 14-50 outlet, install a pigtail on the Rivian Wall EVSE, and swap the breaker in the load center to run the EVSE at 48A? No. That is not okay. The would be several code violations.

Now if you wanted to ditch the NEMA 14-50 and simply repurpose the wiring to hardwire the Rivian Wall EVSE and swap the breaker to support 48A continuous load (60A breaker).... that may be okay... So long as the load center has the capacity and your wiring is rated appropriately.

 

[Livinginkaos]

Or switch out the recep to a 60A rated and put a 60A rated pigtail on the charger (load center capacity assumed). Honestly, I would always hardwire anyway. For an item that 90% of the time will be used when you are sleeping or not around, one less potential hazard to consider. If you need to use the same charger in two places, buy another charger. Not that expensive and you'll enjoy not having the hassle of lugging it around.

 

[rhumbliner]

Now if you wanted to ditch the NEMA 14-50 and simply repurpose the wiring to hardwire the Rivian Wall EVSE and swap the breaker to support 48A continuous load (60A breaker).... that may be okay...

No, that would not be okay. Circuit breaker size is determined by the size of the wiring in the wall — their only function is to prevent the wiring from overheating and causing a building fire. Where you are getting confused is the NEMA code that requires continuous loads to be down rated by 20%. Thus a 50-amp circuit breaker can handle 50-amp loads for short durations but if the load is continuous, i.e., as in charging an EV, then the load must be down rated to draw only 40 amps. The only way to achieve 48-amp continuous loads for charging an EV is to replace the 6-AWG NM-B wire with 4-AWG NM-B wire and then you can install a 60-amp breaker.

Cerrowire Resources - Ampacity Charts

 

[ERivTruck]

Are you asking if you can keep the NEMA 14-50 outlet, install a pigtail on the Rivian Wall EVSE, and swap the breaker in the load center to run the EVSE at 48A? No. That is not okay. The would be several code violations.

Now if you wanted to ditch the NEMA 14-50 and simply repurpose the wiring to hardwire the Rivian Wall EVSE and swap the breaker to support 48A continuous load (60A breaker).... that may be okay... So long as the load center has the capacity and your wiring is rated appropriately.

Sorry all, I was not specific. Yes, I was hoping to use the existing wiring, ditch the NEMA 14-50 and just wire right up to the Rivian Wall EVSE. The goal (for me) would not to have to tear up the basement to re-run new wiring for the Wall EVSE when I can repurpose the existing run of wire!

 

[ERivTruck]

Is there an easy way to determine if the wiring is 6-AWG or 4-AWG?

 

[O. horridus]

From Rivian

I have a Wallbox Pulsar Plus 48A hardwired charger that I had installed by an electrician, and that also specifies 6AWG on a 60A breaker.

I think it is incorrect to say the Rivian Wall Charger requires 4AWG for a hardwired installation.

 

[rhumbliner]

Is there an easy way to determine if the wiring is 6-AWG or 4-AWG?

It's printed on the jacket of the wire. If you can't access the jacket you can use a micrometer to measure the diameter of the bare wire.

https://www.solaris-shop.com/content/American Wire Gauge Conductor Size Table.pdf

 

[rhumbliner]

I think it is incorrect to say the Rivian Wall Charger requires 4AWG for a hardwired installation.

Please read the note at the bottom of the table:

* These typical wire sizes are based on the 90°C column in the National Electrical Code.

The 90º C column is for THHN and similar wire. The OP has existing, in-wall, wiring which is likely NM-B which means you need to read down the 60º C column. Since the OP simply wants to replace the existing 14-50 receptacle with the Rivian Wall Connector he needs to set the amperage to 40 amps.

 

[O. horridus]

Yes I'm aware. My installation is using 6/3 NM-B in EMT mounted inside my garage. By a licensed electrician with EVSE experience and permitted/inspected by the city. (Also, on a different property, I have a 60A sub-panel wired to the main panel with a 100' run of 6/3 NM-B. Also installed by a licensed electrician with permits/inspection.)

Since the OP simply wants to replace the existing 14-50 receptacle with the Rivian Wall Connector he needs to set the amperage to 40 amps.

That's an option, but what the Admiral said is not wrong - I'm pasting what he said, adding back in the part you removed, and adding emphasis:

Now if you wanted to ditch the NEMA 14-50 and simply repurpose the wiring to hardwire the Rivian Wall EVSE and swap the breaker to support 48A continuous load (60A breaker).... that may be okay... So long as the load center has the capacity and your wiring is rated appropriately.

 

[rhumbliner]

Yes I'm aware. My installation is using 6/3 NM-B in EMT mounted inside my garage. By a licensed electrician with EVSE experience and permitted/inspected by the city.

So my question is, why on earth would your electrician install NB-B inside EMT? It's not a code violation but it certainly is overkill for no gain. I suspect your electrician happened to have NM-B on his truck and just decided to use that. Once you install EMT it would have been smarter to install THHN-2.

'm pasting what he said, adding back in the part you removed, and adding emphasis:

I wasn't hiding anything or ignoring what was said. I'm simply pointing out that installing a 60-amp breaker on 6-AWG NM-B wire is a code violation and a fire hazard. Please read the links I've included above.

 

[CommodoreAmiga]

No, that would not be okay. Circuit breaker size is determined by the size of the wiring in the wall — their only function is to prevent the wiring from overheating and causing a building fire. Where you are getting confused is the NEMA code that requires continuous loads to be down rated by 20%. Thus a 50-amp circuit breaker can handle 50-amp loads for short durations but if the load is continuous, i.e., as in charging an EV, then the load must be down rated to draw only 40 amps. The only way to achieve 48-amp continuous loads for charging an EV is to replace the 6-AWG NM-B wire with 4-AWG NM-B wire and then you can install a 60-amp breaker.

Where did OP say they had NM-B wire? Either I didn't see that, or you're making assumptions...

I've seen plenty of NEMA 14-50 outlets installed with 6AWG THHN, and there would be no need to replace that wiring if converting from a NEMA 14-50 outlet to a hardwired EVSE.

 

[rhumbliner]

Where did OP say they had NM-B wire? Either I didn't see that, or you're making assumptions...

Good point. I was making an assumption and erring on the safe side. You, on the other hand, made an assumption that erred on the side of a code violation and fire hazard.

 

[O. horridus]

why on earth would your electrician install NB-B inside EMT

It's run on the surface of the wall at waist level under a window in an unheated detatched garage. Not sure if it's required by code or not, but sure seems to be good practice for a cable like that which is exposed to physical damage (e.g. me being careless when carrying a shovel), and the EMT plus fittings only cost like $50.

And yes, the NM-B was used because I have some left over from a previous wiring job, and the electrician was able to use that and save me $100.

 

[O. horridus]

Regardless, to address the original question:

If you have a NEMA 14-50 and want to replace it with a hardwired Rivian charger, this is possible. You have to consider panel capacity, breaker size, and wire size. If you don't have the right wire size you will have to either rewire or use the existing wire and turn down the current on the Rivian charger. IMO the best thing to do is get some quotes. From multiple electricians, because they will be all over the place.

I would not do it yourself based on advice from the internet.

 

[CommodoreAmiga]

Good point. I was making an assumption and erring on the safe side. You, on the other hand, made an assumption that erred on the side of a code violation and fire hazard.

No, I did not.

You need to re-read my post:

Are you asking if you can keep the NEMA 14-50 outlet, install a pigtail on the Rivian Wall EVSE, and swap the breaker in the load center to run the EVSE at 48A? No. That is not okay. The would be several code violations.

Now if you wanted to ditch the NEMA 14-50 and simply repurpose the wiring to hardwire the Rivian Wall EVSE and swap the breaker to support 48A continuous load (60A breaker).... that may be okay... So long as the load center has the capacity and your wiring is rated appropriately.

 

[ERivTruck]

WOW!!! All this info just blew my head up! Dip switches, wire diameters, NM-Bs, phalanges (Friends), uggg. My biggest problems are the orientation of the interior garage wall and the ability to "drill" into the wall and the foundation to hit the basement entry point, then run wiring across the entire length of the basement (about 60 ft) to the fuse panel. Now that the basement is finished, I'd hate to have to do that AGAIN. So the 50 AMP NEMA was installed before the basement was sealed up. I'll have to pull the plug off and see if there is enough wiring in the box to see what the wire is rated at. I am hoping that it was "upsized" to protect for future power needs.

 

[Wildabeest]

To be clear, NEMA 14 and 14L devices are 3-pole / 4-wire devices. Poles denote the number of current carrying wires and in this case the 3 poles are hot-hot-neutral. The safety ground should not be carrying any current.

NEMA Connectors

And also note that the Rivian Home Charger does not contemplate a “neutral” wire. Only two hots and a ground per diagram below. In my case the charger is wired directly to my main panel where neutral and ground are bridged anyhow, so I guess it doesn’t really matter. I chose to use the neutral wire in the 6/3 Romex for the ground though because it’s a heavier gauge wire and shielded vs. the bare solid copper wire.

 

[Wildabeest]

WOW!!! All this info just blew my head up! Dip switches, wire diameters, NM-Bs, phalanges (Friends), uggg. My biggest problems are the orientation of the interior garage wall and the ability to "drill" into the wall and the foundation to hit the basement entry point, then run wiring across the entire length of the basement (about 60 ft) to the fuse panel. Now that the basement is finished, I'd hate to have to do that AGAIN. So the 50 AMP NEMA was installed before the basement was sealed up. I'll have to pull the plug off and see if there is enough wiring in the box to see what the wire is rated at. I am hoping that it was "upsized" to protect for future power needs.

You’ll want a minimum (that means a gauge value of 6 or less) of 6 gauge wire for the Rivian Home Charger. 6/3 Romex is a common wire for NEMA 14-50 outlets, so there’s a good chance you’re OK. 6/3 Romex has 4 wires (which is what you need for the NEMA14-50 outlet), but you’ll only use 3 of them if connecting directly to the Home Charger. Use either the white wire or bare wire for the ground, and the black and red wires for the two hot wires. Whichever wire you don’t connect to the charger should also be disconnected in your breaker panel.

 

[SANZCO2]

You’ll want a minimum (that means a gauge value of 6 or less) of 6 gauge wire for the Rivian Home Charger. 6/3 Romex is a common wire for NEMA 14-50 outlets, so there’s a good chance you’re OK. 6/3 Romex has 4 wires (which is what you need for the NEMA14-50 outlet), but you’ll only use 3 of them if connecting directly to the Home Charger. Use either the white wire or bare wire for the ground, and the black and red wires for the two hot wires. Whichever wire you don’t connect to the charger should also be disconnected in your breaker panel.

6/3Romex has a max rating of 55 amps. You need you need 6 awg THHN/THWN 75C in conduit to get the 65 amp rating.

 

[ERivTruck]

6/3Romex has a max rating of 55 amps. You need you need 6 awg THHN/THWN 75C in conduit to get the 65 amp rating.

So what happens if I just use the wire from the NEMA 14-50 instead of the THHN/THWN 55 amps versus 65 amps? I know that would increase my charge time, but we should only be talking a few hours more overnight. Is there any other benefits in going to 65 AMPs?