Dedicated Circuit

This is a topic where you will get different and conflicting opinions. I run three dedicated 20A circuits. After I installed them, some friends said I should have run four not three. That's how this hobby sometimes goes. Someone may say you missed the holy grail by not doing "X". IMO I think you simply need to try plugging your gear into and your circuit and conditioner in different combinations and go with the result that sounds best to you. FWIW I run 430W mono amps in 2 of the dedicated circuits and run most of my other equipment into a power conditioner that is plugged into the 3rd dedicated circuit. I've tried other combinations. I found having everything plugged into a dedicated circuit helped lower the noise floor overall and it provided me an improvement in my overall SQ--in my system. YMMV

audiosaurusrex OP

38 posts
06-15-2019 12:17pm

So from what I’m told by the electrician because I have 100amp service there is no way to separate the “phase”.

" there is no way to separate the “phase”
What does that mean?

Hi jea48
electrician said that with 100amp service everything on the electrical panel is on the same “phase”. While I have a dedicated circuit it still is subject to influences of the rest of the house.
I don’t know if this is accurate or true. Need to do some research on this.

@ audiosaurusrex


I think you misunderstood what the electrician said.

In the typical US residential neighborhood the houses are fed from a single phase step down isolation type transformer. The secondary winding is center tapped. From the two outer most leads, legs, of the winding there is a voltage potential of 240Vac nominal. These two leads, legs, are called the Hot Ungrounded conductors.

From either of the two Hot Ungrounded leads, legs, to the center tap lead, leg, there is a voltage potential of 120Vac nominal. The center lead, leg, is intentionally grounded, connected, to earth at the electrical service equipment panel of the house making it the Grounded Conductor, the Neutral Conductor.

The winding is called a Split Phase secondary winding.

So yes there is only one phase but there are two 120Vac Lines.
Line 1 (L1) and Line 2 (L2). The two Hot 120Vac Lines, legs, are 180 degrees out of phase with one another.


Can one Line, leg, have loads that are connected to it putting AC noise back on it that are noisier than the other Line? Yes it can. Can the noisy Line still have an affect on the Other Line? Yes but to a lesser degree. Depends.

Best thing to do is not install the branch circuit breaker for a dedicated line for audio or video equipment in close proximity, (therein directly across from or directly above or directly below), to a know circuit that has a noisy load/s connected to it. The further away the better. (Note: Directly across from is the same Line as the dedicated circuit breaker. Directly above or directly below the dedicated circuit breaker is the opposite Line, leg.

Here is a good video on how a transformer with a split secondary winding works.
https://www.youtube.com/watch?v=eVamt9IdQd8

@ jea48,
Thanks very much, I really appreciate the detailed response and learned a great deal. So when my electrician installed the 20amp circuit breaker it is in fact right below two other 20amp breakers for the air conditioning units 20amp breakers,(two of them).
So should this be moved to the other leg or down further with separation between them? I think when these guys work they like to keep things all together nice and neat.