Overhead triplex feeder termination question

ThomasB · Jun 24, 2023

I have 6-6-6 triplex overhead that I'm running to a detached garage. At the weatherhead at the garage I'm going to splice 8 guage thhn copper to run down to the sub panel (approx 5' max of 8 guage at both ends of the run). This feeder will be on a 50a breaker.
Does anyone see any issues with this? Everywhere I've looked gives me different answers on the 50a, 8 guage part.
For reference, the 8 and 6 guage are 90°c, and the terminals on the breaker are of course 75°c. 8 guage will be in pvc from the weatherhead to inside the subpanel. Will have a drip loop. Detached garage will have a ground rod. The run already uses 8 guage at the main breaker end which is why I'm doing it this way. The run is already there, so I'm going to use it instead of buying new. I think this covers just about everything.

Megawatt · Jun 24, 2023

ThomasB said:
I have 6-6-6 triplex overhead that I'm running to a detached garage. At the weatherhead at the garage I'm going to splice 8 guage thhn copper to run down to the sub panel (approx 5' max of 8 guage at both ends of the run). This feeder will be on a 50a breaker.
Does anyone see any issues with this? Everywhere I've looked gives me different answers on the 50a, 8 guage part.
For reference, the 8 and 6 guage are 90°c, and the terminals on the breaker are of course 75°c. 8 guage will be in pvc from the weatherhead to inside the subpanel. Will have a drip loop. Detached garage will have a ground rod. The run already uses 8 guage at the main breaker end which is why I'm doing it this way. The run is already there, so I'm going to use it instead of buying new. I think this covers just about everything.

By definition of the NEC if you are feeding a sub panel then you must pull an equipment ground from the source of power to the sub panel. Then no ground rod is required. As far as the sizing of your conductors you are supposed to use the 75 degree Celsius chart not the 90 degree section. # 8 is fine for a 50 amp supply and I’m assuming that you are not having this inspected.

ThomasB · Jun 25, 2023

Megawatt said:
By definition of the NEC if you are feeding a sub panel then you must pull an equipment ground from the source of power to the sub panel. Then no ground rod is required. As far as the sizing of your conductors you are supposed to use the 75 degree Celsius chart not the 90 degree section. # 8 is fine for a 50 amp supply and I’m assuming that you are not having this inspected.

At the barn sub panel (where this feeder came from) the neutrals and grounds were bonded. What would be the issue with doing it that way again, considering it's been that way for over a decade without any issue in the barn? Pulling a separate ground overhead isn't something I can do because I can't climb ladders (leg braces), so if I can get away with not hiring someone then that's what I want to do. And no, this will not be inspected.

Megawatt · Jun 25, 2023

ThomasB said:
At the barn sub panel (where this feeder came from) the neutrals and grounds were bonded. What would be the issue with doing it that way again, considering it's been that way for over a decade without any issue in the barn? Pulling a separate ground overhead isn't something I can do because I can't climb ladders (leg braces), so if I can get away with not hiring someone then that's what I want to do. And no, this will not be inspected.

We are supposed to tell you the correct way of electrical and not cut corners. By doing this your way is against the NEC regulations. I cannot advise you any further.

ThomasB · Jun 25, 2023

Megawatt said:
We are supposed to tell you the correct way of electrical and not cut corners. By doing this your way is against the NEC regulations. I cannot advise you any further.

I understand completely. I was just trying to see if there was another way to ground the subpanel besides running a ground wire all that distance. So two ground rounds at the structure six feet apart wouldn't work or be acceptable?

Megawatt · Jun 25, 2023

ThomasB said:
I understand completely. I was just trying to see if there was another way to ground the subpanel besides running a ground wire all that distance. So two ground rounds at the structure six feet apart wouldn't work or be acceptable?

I’m saying it is not by code.

ThomasB · Jun 25, 2023

Megawatt said:
I’m saying it is not by code.

But if I had pulled a permit for this under the 2005 code, it would be perfectly acceptable and safe, and an ahj would pass it today. Weird how electrons behave differently depending what year it is.
All joking aside, thanks for your help and taking the time to answer some questions. I also understand that all your answers must conform to the NEC, and that you can't/won't deviate from that, and I respect that. Thank you again.

Megawatt · Jun 25, 2023

ThomasB said:
But if I had pulled a permit for this under the 2005 code, it would be perfectly acceptable and safe, and an ahj would pass it today. Weird how electrons behave differently depending what year it is.
All joking aside, thanks for your help and taking the time to answer some questions. I also understand that all your answers must conform to the NEC, and that you can't/won't deviate from that, and I respect that. Thank you again.

Good luck my friend