Dedicated circuits

where to buy a magnetic breaker?

You won’t buy em for your electrical panel... Only T-M, Thermal-Magnetic, breakers are available. The Thermal protection unit of the breaker is for overload protection of the branch circuit wiring. The magnetic unit provides short circuit protection. It usually trips the breaker open in a matter of milliseconds. An electrical short circuit can cause a dangerous electrical explosion if not cleared quickly...

The only place I can think of where a Magnetic circuit breaker is used is on a piece of equipment. It is never used to protect branch circuit or feeder wiring...

Per NEC, UL, NEMA, only the manufacture’s breaker type/stye can be used in an electrical panel. A label on the back side of the electrical panel’s breaker cover door lists the manufacture’s type/style(s) for the breaker(s) that can be used in the panel. Using the wrong breaker will void the UL Listing.

Here is a video of the inside of a circuit breaker and how it works. Note the circuit breaker that is used for the demonstration is a EATON type/style BR breaker, not a Square D QO circuit breaker. A Square D QO breaker works on the same principal but in my opinion is of a better build quality.

The guy making the video does a pretty good job except, imo, when it comes to his personal electrical safety.

@jea48  , thank you for clarifying that for us. 

I have had a single dedicated circuit and receptacle where my Shunyata Triton V1 is connected. Two mono block amps phono preamp preamp stresmer DAC turntable are all plugged into the Triton. This circuit is new with 12 gauge Romex.  The position of everything requires almost 15 foot power cables to the amplifiers  This makes it impossible to upgrade because I would have to purchase very expensive custom lengths that would have no resale value.  Instead of moving the outlet closer, I’ve been planning to change it to 10 ga.   I remember reading Or watching a video with Michael Fremer and I’m pretty sure he recommends one single circuit so I could run the 10 gauge and then also add a second receptacle close to the amplifiers so I could use standard length cables. I know a lot of people do what the OP did and have a completely separate circuit for the amplifiers. Nothing about money I just want to do what’s best for the sound.  I’ve added the amp ratings for all my gear and the total is less than 15 A so electrically I don’t need two dedicated circuits.  Does anyone know if I am remembering correctly, and if there is a reason to have everything, going to one circuit?