I Have A Kiln on A 2 Pole 50 Amp Breaker , That Only Gets Used Rarely So I Thought I Could Use It For A Brand New Wall Oven In The Kitchen.so Turned of The Breaker and Opened to J-Box Disconected the 3 Prong outlet All Three Wires Were White...? But on One Had a Red Tape on it ,one Had Green tape and The Other had None ,So`s I Figure it Must Be The Black. I Ran 3 - 25 feet of 8 Gauge Wires 1 Red ,1 Green, 1 Black, Install the Oven and Acorrding to Instructions Put The Red To Red The Unmarked One Which I Figured Was the Black to The Black and The Green To The Copper Wire. Turn on The Breaker .... Nothing ! So I Opened The Panel Cover [All Square D Breaker Panel And What The !,, Theres Two Wires Coming Out Of The Bottom of The 50 Amp Breaker .... The Unmarked One And The Red One and Then The Green One I Thought Was The Ground It Was Conected to The The Top Bar ,, HELP

I'm remodeling a "A" frame mountain cabin with open, exposed ceiling rafters. Trying to run all electrical wiring for lights, ceiling fan, thru a single wire channel (armor flex or metal or plastic channel). Main channel will run along the roof peak with junction boxes as needed. How many single strand (12 g) wires are allowed inside the channel. Can I use a plastic channel? Will wire heating be a problem?