Help with DIY dedicated circuit


I am wanting to install a dedicated circuit for my amp, but getting from my panel to the wall behind my amp is going to be difficult. As I was investigating in my attic, I realized that when I changed my stove from electric to gas, the unused 30 amp Romex 10/3 wire will reach within 15 feet of where I want the wall outlet. Do I install a junction box and run Romex 10/2 to the new wall outlet and use the 30 amp breaker? What is the best way to connect the wires in the junction box?
128x128jonandfamily
For those who may not be aware, the many posts Jim (Jea48) has provided here over the years about electrician-type matters make it abundantly clear that his background and expertise in this area are second to none. Second to none not only at Audiogon, but I would feel safe in saying among electricians everywhere.

I for one have learned a great deal from his posts over the years, despite the fact that I have a very extensive background in electronic design. And the help he has provided to a great many members here has earned widespread recognition and appreciation.

Regards,
-- AlĀ 
Post removed 
Seems I owe an apology to several in here. It happens, my turn to eat crow.

Lesson learned, NEC updated, probably a couple of times since I was in the field. With that said, I'll have to double check any advice I try to contribute.
I feel like the village idiot...lulz. My apologies to those I had conflict with.
@mental

Apology accepted.

Just a guess the last NEC code addition book you were using before you retired was the 1999. The NEC really started changing and adding things in the 2005 edition. Even more changes in 2008, 2011, 2014, and 2017. Probably the most changes in 2008 and 2014.

Jim
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