Help With Running New Sub Panel in Garage

joedadog

I ran some 8/3 wire from the basement to the attic (About 100 feet) a few years ago, planning to add a sub panel in the garage for outlets and a 220 line (30 amp). The time has come to finish the job. Can someone tell me what size breaker to put in the basement, and the size of panel in the garage? Should I have run 6/3 for the job? I do not want to buy new wire. I want to run a few circuits with 12 gauge wire for outlets, a 20 amp circuit for a fan in the family room, a 220 line for a electric heater in the family room. Any help would be helpful.

chris75

If the 8/3 you ran was romex, then the maximum breaker shall be 40amp, and you can install any size sub-panel you think you might need. I don't know what the load is so can't say if #8 is too small or not...

joedadog

I hope it is romex. It has three wire wrapped in a black plastic covering. Is that ok? I have lots of experience with household wiring, all 14 and 12 gauge stuff though. I will put a 40 amp breaker in the basement, three 20 amp and two 30 amp breakers in the garage. One 30 for the heater, one 30 for a possible welder or something (L6-30R), and the rest for outlets, lights and a fan. Is that ok.

LawnGuyLandSparky

How tall is your house?!

joedadog

Two story colonial. I will be using all of the 100 feet. I hope it is enough.

LawnGuyLandSparky

Joe, a 2 pole 40 breaker is you max. That's 40a, 220v. If your 30a circuit is for a welder or something you'd use only sporatically, 40a should do nicely for you considering the loads you've listed. Your best (and probably cheapest) bet is a 100a 12-circuit panel with an auxiliary ground bar, and the neutral bar isolated from the panel backbox. You don't need a main, just the 40a 2-pole breaker in your main panel.

Stubbie

You don't seem positive this is romex if you are interested in code compliance this 8/3 cable needs to be 8/3 with ground (4 - wires total). You are not allowed a 3 wire without ground to a sub-panel in the same dwelling as the service equipment. You do not bond ground and neutral at the sub-panel this is a code violation. You keep neutral and ground separate at the sub-panel. You can have a main breaker in the sub or it can be main lug only. A grounding electrode is not required for the sub-panel.

Should be like this........

Attached Thumbnails

 

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Stubbie

joedadog

Thanks, Stubbie. You answered my question. It is 4 wire and your picture will help me hook it up without any problems. Thanks again.

Stubbie

HI Joe

Your welcome, glad the picture helps. You have that 40 amp feed pretty close to loaded at times so watch your load management closely.... good Luck

__________________
" One nice thing about the NEC articles ... you have lots of choices"

Stubbie