Thank you in advance for your advice!
My project is to install a 220v-240v NEMA 14-50 outlet at my house’ s attached garage, which is nearly 65 ft/one way, from the house’ s main electrical panel / newer 4 wires 200amp installation, Grounding is done via 2 ground rods+to the copper main water line. The panel’ s current highest load is a 2-pole 40amp / HVAC, the house is under 1900 sq. ft.
I had access to left-over wires; THWN-2 THHN AWG #8 & AWG #6, so From the main electrical panel thru the attic, I utilized the left over AWG #8 (2hot+1Neutral) and AWG #6 (Ground), via EMT & flex conduit secured to the rafters / 4 ft intervals.
However, rather than sticking to the original plan and finishing with a NEMA 14-50 outlet at the attached garage to conclude the project by installing a 2-pole 40amp circuit breaker at the main electrical panel, I am considering to utilize the pulled wires along with a freebie panel, Cutler Hammer BR816L125RP rated at 125amp, and turn it into a sub panel at the attached garage’s area, and then install a NEMA 14-50 outlet / fed with a 2-pole 40amp circuit breaker at the sub panel. Given that the freebie panel is equipped with only one Bar, I will isolate Neutral from Ground by installing a Ground Bar and connecting ground wire to it / AWG #6.
The reason for the subpanel installation is to maximize the use of the AWG #6 & #8 wires that I have greatly appreciated pulling thru the flex conduit and account for possible future modification, as well as to install couple service outlets in the garage area near the planned subpanel’ s area without having to pull wires thru the finished garage walls from other service outlets.
Given the above information, including the AWG #6 & #8 wires’ length; What is the maximum breaker size that I can utilize at the main electrical panel to feed the garage’ s subpanel, i.e can I install a 50amp or 60amp 2-pole , or even higher rated circuit breaker? While still installing NEMA 14-50 outlet / fed with a 2-pole 40amp circuit breaker at the sub panel
Appreciate your expertise and honest opinion!