8 gauge wire implications with a Tesla Gen 3 Charger

[GigaToronto]

I paid my electrician to install a nema 14-50 outlet with 8 gauge wire instead of 6 gauge as I thought I would just use the mobile connector with the adapter to charge. My EDD is May 6 for the MYLR and with the news that Tesla won't include the mobile connector with a car purchase anymore, I was thinking it is almost the same price to buy a gen3 Tesla charger vs a mobile connector. Now if I consider installing a charger with the 8 gauge wire, is this still possible? If so, what would be the possible draw backs with this setup?

 

[jjrandorin]

We dont know if you will get it or not with the car you previously ordered (im sure we will find out in the next few days though), and a wall connector can be setup at various amps so its possible to use it and charge at the same speed you planned to previously.

There only drawback would be "it can go faster than that" and making sure you set the wall connector up for the breaker / amp that is supported by your installation.

 

[GigaToronto]

Thanks. Before installation of the 14-50, my electrician did the analysis on my 100 amp set up and concluded that I could support a charger with 6 gauge wire. I decided against it given what I knew at the time and it cost $200 more than 8 gauge. Now It will probably cost more to rip out the 14-50 outlet and attach the charger as well...

 

[sleepydoc]

We dont know if you will get it or not with the car you previously ordered (im sure we will find out in the next few days though), and a wall connector can be setup at various amps so its possible to use it and charge at the same speed you planned to previously.

There only drawback would be "it can go faster than that" and making sure you set the wall connector up for the breaker / amp that is supported by your installation.

Agreed. What size breaker did your electrician install? If you’re running the wire it doesn’t make a lot of sense to wire a 14-50 outlet with 8 gauge instead of 6 gauge wire.

Either way, I’d get the wall connector and just set it for the appropriate amperage. Realistically I think you’ll be happy with the charging speed.

 

[GigaToronto]

Agreed. What size breaker did your electrician install? If you’re running the wire it doesn’t make a lot of sense to wire a 14-50 outlet with 8 gauge instead of 6 gauge wire.

Either way, I’d get the wall connector and just set it for the appropriate amperage. Realistically I think you’ll be happy with the charging speed.

Sorry why didn't it make sense to get 8 gauge with 14-50? Just trying to understand. It was a 40amp breaker.

 

[jcanoe]

If you are installing a 240V/40 amp circuit then 8 gauge NM-B (Romex) is adequate. For a 50 amp circuit 6 gauge NM-B wire would be required, only cost a little more for the materials (the labor cost would be the same) as the 8 gauge.

If you don't receive the Tesla Gen2 Mobile Connector with the vehicle you can purchase this from the Tesla store. I expect that now that Tesla no longer includes the Gen2 Mobile Connector with every new Tesla vehicle the out of stock inventory problem will quickly disappear.

If you decide to get the Gen3 Wall Connector know that the Wall Connector can be configured for any of 15/20/30/40/50/60 amp circuits. When used on a 40 amp circuit the Wall Connector would enable charging at 32 amps, same as the Gen2 Mobile Connector. Reasons to get the Wall Connector include it being fully weather rated and having a longer 24 foot charging cord.

 

[Sophias_dad]

I paid my electrician to install a nema 14-50 outlet with 8 gauge wire instead of 6 gauge as I thought I would just use the mobile connector with the adapter to charge. My EDD is May 6 for the MYLR and with the news that Tesla won't include the mobile connector with a car purchase anymore, I was thinking it is almost the same price to buy a gen3 Tesla charger vs a mobile connector. Now if I consider installing a charger with the 8 gauge wire, is this still possible? If so, what would be the possible draw backs with this setup?

It is entirely possible to install the HPWC with 8 gauge wire, but you need to provision it to have a 40 amp breaker(if the 8 gauge is NMB, aka not in conduit), or 50 amp breaker(if the 8 gauge is in conduit). It'll be interesting to see what sort of breaker is installed for your outlet right now(and what wiring was used). If its currently a GFCI breaker you might want to have it swapped out with a 'normal' breaker.


TBH I suspect that since you signed up for the car when it included the mobile connector, if they >don't< automatically include it the slightest amount of bitching will get it for you free.

 

[GigaToronto]

Thanks for the info. So if I set the gen3 at 40 amps, then I should be OK with 8 gauge wire given my set up. Also, the corded mobile connector and the regular mobile cord are both sold out on the Tesla Canadian site. As a shareholder and customer in waiting, I hope they know what they are doing by excluding the cable with new purchases.

 

[jcanoe]

Thanks for the info. So if I set the gen3 at 40 amps, then I should be OK with 8 gauge wire given my set up.

Yes, the Wall Connector will function correctly, enable charging at 32 amps maximum on the 40 amp circuit. The Wall Connector is designed to be hard wired, does not come with a plug. The NEMA 14-50 receptacle would not be used, would be removed if already installed. Also, if the current 40 amp circuit breaker is a GFCI type circuit breaker this can be replaced with a standard (much less expensive) double pole 40 amp circuit breaker.

 

[Sophias_dad]

Thanks for the info. So if I set the gen3 at 40 amps, then I should be OK with 8 gauge wire given my set up. Also, the corded mobile connector and the regular mobile cord are both sold out on the Tesla Canadian site. As a shareholder and customer in waiting, I hope they know what they are doing by excluding the cable with new purchases.

Just as an FYI I wouldn't entertain getting the $400 CMC, ever. The UMC is a considerably better deal, at $275 plus $45 for the 14-50 adapter, and you can charge on almost any outlet(if you buy the right adapter, of course). You lose 8 amps of charging (32 instead of the 40 of the CMC), but if I'm gonna spend $400 for a CMC plus $100-$150 for the GFCI to drive it, plus $50 for a decent outlet, It becomes MUCH cheaper to just get the $495 HPWC. I think the only case where the CMC might make sense is if you have your own home PLUS a favorite destination that both have a 14-50(and both those 14-50's are wired/breakered for 50 amps!)

 

[gfunkdave]

I paid my electrician to install a nema 14-50 outlet with 8 gauge wire instead of 6 gauge as I thought I would just use the mobile connector with the adapter to charge. My EDD is May 6 for the MYLR and with the news that Tesla won't include the mobile connector with a car purchase anymore, I was thinking it is almost the same price to buy a gen3 Tesla charger vs a mobile connector. Now if I consider installing a charger with the 8 gauge wire, is this still possible? If so, what would be the possible draw backs with this setup?

If your electrician used Romex it can be on up to a 40A circuit. If they used individual wires in conduit you can have a 50A breaker.

If you decide to buy the wall connector, you'll just put that on the wall instead of an outlet.

There are no drawbacks. An electron is an electron. You will just not have a mobile connector for when traveling, but you can use superchargers of course.

 

[voom500]

I'm going with the 8 gauge in conduit here with the 50A breaker and 14-50 receptacle. Install is happening this week. I plan on using the UMC which will max out at 32A. That's plenty for our work day driving; not really much difference in the 32A vs 40A when you think about charging multi hours overnight.

 

[SambaMystic]

This is exactly my current situation. 3.5 years ago I had my boyfriend install a 14-50 for me and he used 8 gauge and a 50 amp breaker. I have been using the mobile connector all this time at 32 amps (the maximum it would go) which is plenty for my nightly charging of my Tesla 3. Lately I have been getting the error that the amps had to be reduced for overheating and the documentation says it's likely the wiring. With boyfriend no long in the picture, I had an electrician come out and he said for safety reasons I shouldn't have a 50 amp breaker and replaced with 40 amp. (I may have been taken advantage there... I don't know. :-( ) But there wasn't any issue with the wiring. After borrowing a friend's mobile connector and playing around with it, it seems my "pigtail" 14-50 adapter is the culprit. So replacing the mobile connector with everything out of stock, I started to consider the wall connector but then found out about the 8 gauge... but can restrict to 40 amps. blah blah blah. The mobile connector apparently is covered under the warranty up to 40K/4 years so let's see if they can replace mine.

 

[MattM24]

I paid my electrician to install a nema 14-50 outlet with 8 gauge wire instead of 6 gauge as I thought I would just use the mobile connector with the adapter to charge. My EDD is May 6 for the MYLR and with the news that Tesla won't include the mobile connector with a car purchase anymore, I was thinking it is almost the same price to buy a gen3 Tesla charger vs a mobile connector. Now if I consider installing a charger with the 8 gauge wire, is this still possible? If so, what would be the possible draw backs with this setup?

You can’t run a 3rd gen Wall Connector on 8 awg in Ontario period.

NM-B is a US wire. Canada is not in the US. Canada has NMD90 wiring, which can use the 75C ampacity tables if your breakers are 75C rated.

Either run the wall connector on 6 awg on a 60A breaker or keep the mobile connector setup.

 

[GigaToronto]

With the price cut of the corded mobile connector to be the same as the mobile connector with a little bit more speed, I decided that I will order that when it is not sold out. When my car does come, whenever that will be, I will use the mobile connector that comes with the car and the 14-50 adapter. I did check with electrician and it would have been costly to replace the 8 gauge wire. Thanks for everyones comments!

 

[jcanoe]

it seems my "pigtail" 14-50 adapter is the culprit.

Did your installation of the Mobile Connector include supporting the Mobile Connector chassis (electronics unit) or was the Mobile Connector let to hang supported by just the power plug pigtail?

The plug and receptacle are not designed to support additional weight. For best long term reliability the Moibile Connector chassis should be mounted to the wall or otherwise supported.

The Tesla Cable Organizer includes a wall bracket for the Mobile Connector Chassis (see photo #2)

Cable Organizer

 

[Sophias_dad]

You can’t run a 3rd gen Wall Connector on 8 awg in Ontario period.

Where do you get that information? It sounds rather dubious, since the wall connector can be set down to a 15 amp breaker.

 

[MattM24]

Where do you get that information? It sounds rather dubious, since the wall connector can be set down to a 15 amp breaker.

ESA Bulletin 86-1-4

 

[Sophias_dad]

ESA Bulletin 86-1-4

I've read it(https://esasafe.com/assets/files/esasafe/pdf/Electrical_Safety_Products/Bulletins/86-01-4.pdf) and don't see anything about the minimum branch circuit wiring or breaker.

 

[MattM24]

ESA inspectors fail this because of the wifi circuit adjustment on the gen3. Anyone with a phone can change the circuit size and cause a problem.
The gen2 had an internal pot adjustment that is mentioned in the Q and A section and is acceptable.