I am remodeling my home and am in the process calculating the load for a sub panel that will supply power to a portion of the house. The house was built in the late 1040s with an addition constructed in the early 70s. There is a contemporary 200amp load center with integrated service entrance on the exterior of the building. It supplies power to the addition through installed breakers and to the original portion of the house through a subpanel. When the addition was constructed an original service entrance was removed but the service lines were connected back to the new load center through number 4 aluminum SEC without a ground. The number 4 aluminum supplies an 8 breaker load center without a main. Consequently the older part of the house is not grounded. I am remodeling the kitchen and bath in the original house and need to modernize the electrical system. My plan is to run a new 3 wire copper feeder with ground from my 200 amp load center to a subpanel.
The sub panel will supply the following circuits (with energy demand listed as per appliance manufacturer specs):
Total combined load is 155 amps across 2 legs of 120 volt
With 77 amps total per leg, I hope I can reasonably use number 6 copper NM-B with ground fed by a 60 amp breaker back in my main panel. However, I am wondering if I should consider moving up to number 4 copper with 70 amp breaker to provide more capacity? Thanks in advance. My run from the load center to the subpanel is 55 ft.
Thanks!
The sub panel will supply the following circuits (with energy demand listed as per appliance manufacturer specs):
- 20 amp gas range
- 20 amp refrigerator
- 12 amp dishwasher
- 12 amp range hood
- 20 amp counter top circuits x2
- 15amp living room ( existing 6 outlets 1 ceiling light, 1 entry light)
- 15amp bathroom/bedroom/hallway (existing 6 outlets, 2 ceiling lights, bathroom fan)
- 15amp tv room, kitchen lights (existing 3 outlets 2 ceiling lights, 1 entry light)
Total combined load is 155 amps across 2 legs of 120 volt
With 77 amps total per leg, I hope I can reasonably use number 6 copper NM-B with ground fed by a 60 amp breaker back in my main panel. However, I am wondering if I should consider moving up to number 4 copper with 70 amp breaker to provide more capacity? Thanks in advance. My run from the load center to the subpanel is 55 ft.
Thanks!
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