Wire size for distance
I recently discovered that a sub-panel in my garage that feeds a 220v 50 amp plug (5hp air compressor or welder, whatever I am using) has been daisy chained off my dryer wiring in my attic.
The breaker at my main box is a 50 amp. This does not seem safe to me so I would like to replace the 50 amp breaker with a 30 amp and run a new wire from the main box to the dryer with no interuptions. The distance from box to dryer is about 70 feet and all indoors, the origonal wire that I want to replace is aluminum and in bad shape at the point where it was spliced. What size copper wire should I use for 70 feet and 30amps?
Also I am going to put the garage sub-panel on its own 50 amp breaker. The distance to the sub-panel is 95 feet from the main box and I would like to know what size wire would be sufficient for 220v 50 amps at 95 feet, also indoors. I would like to run both wires without conduit through the attic if it can be done safely with these amps and distances. Any advice you can give me would be a great help, I don't like trusting the the guys who sell this stuff retail when a bad piece af advice might mean a fire! Thank you for your time.