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6/3 or 6/4?
- Thread starter allj
- Start date
6/3 means 6 gauge, 3 conductors. The ground wire is always separate. If you are installing a receptacle such as the NEMA 14-50 then you would need to use 3 conductors plus the ground. If you are installing the Wall Connector then you only need 2 conductors plus the ground wire.
If you are planning to install a 60A circuit for the Wall Connector then, by code, you can only use 6 gauge wire if the wire is other than NM-B (Romex type.) The Tesla install guide is not particularly clear on this. You can use 6 gauge wire such as THHN in conduit or metallic clad (MC) wire but if you are using NM-B wire for the circuit the wire would need to be 4 gauge. 6 gauge NM-B wire should only be used on a maximum of 50A breaker.
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iamnid
Active Member
iamnid
Active Member
It's probably in the install manual for the connector. There's simply no place to install the extra conductor (neutral)
It’s recommended to run 3 conductors and a ground if there is any chance that someday you or a future owner might replace that wall connector with a 14-50 receptacle or some other type of ev connector that requires a neutral in addition to the ground.
You can install 3 conductor wiring instead of 2 conductor wire. 3 conductor wire will cost a bit more and would be more difficult to pull through walls and conduit (where required.) 240V hard wired EVSE don't need, don't use the neutral connection so if you ever change to a non-TESLA charging installation you would not need the 3rd wire. If for some reason you wanted the flexibility of a receptacle the NEMA 6-50 does not use the neutral wire.
I thought I had this. I can use the 90 degree rated 6 awg THHN wire in a metal conduit instead of the romex 4awg. However, the installation guide says to use #4 at the terminal block, copper only. Can I disregard this and use the 6 THHN or does the THHN need to be pigtailed with #4awg?? Confused!!
| Voltage and Wiring | Nominal 200-240 V AC single-phase |
| Current Output Range | 12 – 48 amps |
| Terminal Blocks | 12-4 AWG (3.5 - 25 mm2), copper only |
| Supported Conduit Sizing | ¾" (21 mm) default, 1" (27 mm) optional |
| Grounding Scheme | TN/TT |
| Frequency | 50/60 Hz |
Re: Terminal Blocks. The way I am reading this is depending on your circuit rating (15A up to 60A) you can use any gauge (copper wire only) between 12 gauge wire and 4 gauge.
It is not stating 12/4 it is stating you can use wire of different gauges varying from 12 gauge all the way to 4 gauge (as long as the wire is made of copper.)
In my area the difference on a 50 ft roll of Romex between 6-3 and 6-2 is about $20. If it were me I would leave it to the electrician to decide which wire is best; he/she should have the expertise and knowledge of relevant local codes that is needed to make that decision.
From my own install, my father is an electrician and he installed the wall charger with me. We used 6-3 and used the white insulated wire for the ground.
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According to Google - "Circuit breaker terminals are rated for a maximum temperature of 75 °C. ... Conductors having higher temperature ratings, such as 90 °C, may be used; however, the ampacity must be de-rated to that in the 75 °C column."
The maximum amperage allowed for 6 gauge 90C rated THHN wire is 75A; De-rated for 75C using 6 gauge and non NM-B wire, i.e. THWN, you would be limited to 65A. So you are good to go for using a 60A breaker rated for 75C and 6 gauge 90C rated THHN.
I've found this thread very enlightening. I thought that I had done it right but now it is clear that I did not. I originally had an electrician wire up a 20amp circuit for a Clipper Creek LCS-20 charger that I used with a Chevy Volt. At that time I thought that I would buy a Tesla in the future so I had the electrician run 6 gauge wire and told him that I may put a 60amp breaker in there one day. When I bought my M3 three years ago I decided to keep the LCS-20 because even though it was low speed it was fast enough for my daily commute of around 20 miles. If I went farther it would take two night's of charging to get caught up but still was never an issue. I have a Supercharger less than 10 miles from me so my thought was that in the worst case I just needed enough of a charge to make it there. Even after adding a MY I found that the LCS-20 was still fast enough to keep up with the daily driving.
Fast forward to last month when someone gave me a Gen 3 wall charger. I disconnected the LCS-20 and discovered that the electrician had ran both 12/2 romex hooked up to a 20 amp breaker for the LCS-20 and 6/2 romex which was capped and not connected. I disconnected the 12/2, replaced the 20 amp breaker with a 60 amp, wired up the 6/2 romex, and set the Gen 3 charger to 48 amps.
This setup has worked fine for me and my house has not burned down. After reading this thread and doing other research yesterday, though, I reset the Gen 3 to 40 amps and purchased a 50 amp breaker which I will be installing tonight. I never needed the 48 amps and I likely will not need a 40 amp charge rate as I was fine with 16 amps for years. I'd rather that my house did not burn down due to a freak something or other with the wiring. I know that the odds are slim but the code is written how it is for a reason, right? I'll end up with 6/2 romex, 50 amp breaker, and 40 amp charge rate which as near as I can tell gets me code compliant.
Thanks forum.
Fast forward to last month when someone gave me a Gen 3 wall charger. I disconnected the LCS-20 and discovered that the electrician had ran both 12/2 romex hooked up to a 20 amp breaker for the LCS-20 and 6/2 romex which was capped and not connected. I disconnected the 12/2, replaced the 20 amp breaker with a 60 amp, wired up the 6/2 romex, and set the Gen 3 charger to 48 amps.
This setup has worked fine for me and my house has not burned down. After reading this thread and doing other research yesterday, though, I reset the Gen 3 to 40 amps and purchased a 50 amp breaker which I will be installing tonight. I never needed the 48 amps and I likely will not need a 40 amp charge rate as I was fine with 16 amps for years. I'd rather that my house did not burn down due to a freak something or other with the wiring. I know that the odds are slim but the code is written how it is for a reason, right? I'll end up with 6/2 romex, 50 amp breaker, and 40 amp charge rate which as near as I can tell gets me code compliant.
Thanks forum.
