Anyone use this Romex 6/3 cable during install?

[Rocky_H]

What about using 6-6-8 Gray Stranded CU SEU Cable? I already have the 4/3, but found 2 conductor CU SE cable with 65A rating.

SEU is a little less clear on its use and ratings, so I'm not sure. SEU normally gets that 75 degree rating of 65 amps if it's in more open areas, but I did find an NEC reference that said if it gets run inside an insulated wall like Romex is normally used for, it has to go back down to that 60 degree rating, where it's only 55A rated.

 

[JerseyMike]

Hey I had an observation that I thought was interesting on this subject, though I'm not out to trigger anybody - just an observation.

My installation is indeed a Romex 6/3, 60 amp breaker, Tesla V3 charger. After I found this thread, I set the limit on the car to 44 amp, which is 80% of the 55 amps that Romex 6/3 is rated for. Frankly, any difference in charge time between 44 amps and 48 amps has been irrelevant to me.

The observation is that whether this charging system is running 44 amps or running 48 amps as it was before, the 18 foot charging cord supplied by Tesla feels warmer to the touch than the Romex 6/3 does. I've sampled both in several places. Is it not appropriate to take from this observation that the Tesla cord is more of a limiting factor than the house wire? Anyway, I'm not advocating for anything, I just thought it was interesting.

I just did something similar, added a second charger for my lightning and with power sharing I can set the total amp max at any single digit, so was able to set it at 44amp max for the whole system, works great and piece of mind, minimal time difference in charging

 

[dn325ci]

I just did something similar, added a second charger for my lightning and with power sharing I can set the total amp max at any single digit, so was able to set it at 44amp max for the whole system, works great and piece of mind, minimal time difference in charging

I know the militant code people in this thread will not like this comment, but after 3 years of running tests on my setup the 6/3 romex runs lower cable temperatures than the Tesla cable, whether at 44A or 48A. I still set it to 44A because the time factor is not relevant to me, but the 4A difference does not change the outcome.

 

[Cosmacelf]

I know the militant code people in this thread will not like this comment, but after 3 years of running tests on my setup the 6/3 romex runs lower cable temperatures than the Tesla cable, whether at 44A or 48A. I still set it to 44A because the time factor is not relevant to me, but the 4A difference does not change the outcome.

This isn’t surprising. Romex is derated because it can be installed in a hot attic, through insulation, etc. while an equipment cord is assumed to be in free air. So equipment cord requirements are much more lenient.

If you know how your romex is routed and you know it isn’t ever going to be subject to high temperatures, then I personally wouldn’t worry about running it at 60A. But that’s me.

 

[Midnightsun]

I know the militant code people in this thread will not like this comment, but after 3 years of running tests on my setup the 6/3 romex runs lower cable temperatures than the Tesla cable, whether at 44A or 48A. I still set it to 44A because the time factor is not relevant to me, but the 4A difference does not change the outcome.

Have mentioned this several years back. The charge cable is rather small in comparison, bet you it is no bigger than 8 awg.