Wiring question

Hi, I'm installing a 125 amp sub panel in my garage for power tools. Will be installing a 70 amp breaker in the load center to feed the sub. Will be installing 240v circuits along with 120v. What wire size do I need to go with from load center to sub? Distance is bout 30'.
TIA,
Tony
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You need three #4 copper wires and a #8 green or bare copper wire for the ground. You could possibly use #6 if your load calculation comes to 65A or less, but you must use 75C rated cable in this case, such as SER. Number 6 copper NM cable can't be used unless you limit the breaker to 60A. If running individual THHN wires, you could also use #4 for the two hots and #6 for the neutral as long as some of your load has 240V only appliances.
-- Mark Kent, WA
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This is Turtle.
Most everything i do is Commercial and i tend to over do things as residentiual wiring goes but here is my view on it.
You can get you some 3 wire # 4 / with Naked ground and all in casing. You need to get it in TW, THW or THWN types strands and your rating will be above any 70 amp breaker you may want to use. You will have a black and red to use for your two hots and a white used for your common and a naked ground wire used for your ground wires to the appliances or the sub panal. You need to try to keep the naked gound seperated from the white common wire for you don't want the naked ground being used as the common in the circuits.
Now if you want to use some THHN type wire in conduit. you can use #6 for the two hots and some #8 for common and some #8 for the naked ground or ground wire only and if coated must be green.
Yea, i know I over killed it but i can't run the line on wire but alway fair on the larger side.
TURTLE
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