How to A/B Test Power Cables & Interconnects?

robert, first, I’m not an electrician, so take anything I say with a grain of salt. That being said, I have been in residential construction for 30 years. I’m in the Pacific NW. I’ve never seen an electrician here use a metal box in a home without good reason. Something heavy, like a ceiling fan, or remodel work in an older home. I wouldn’t think audio AC cables would rise to that level, given a quality box like a Pass & Seymour, etc.I wouldn’t run a ground like you describe. An electrician may or may not, I’m not sure. Generally, from my limited understanding, it’s not advisable to just bond grounds together at random. I’d have two separate circuits, or only one.

P.S. My panel has two bars, one on the right, one on the left. Grounds and neutrals connected to the nearest spot. Both bars are connected behind the main breaker I believe, and then to the ground lug.

I am not an electrician either, though was once fairly handy with the electrical code, but that was a while ago. Just went down to my panel, as expected, I have a dual single pole breaker that both trip at the same time (not a common 2-pole), however, perusing HD website and I can't find this style any more, so that tells me that maybe they don't make them any more?

Perusing the web, it does not appear that doing this is verboten, but, like my installation, you would (for residential) need a breaker that disables the circuit at the same time. That could be tough with a breaker panel, easy with a ganged breaker in a box. 

The easiest thing, that would not confuse inspectors, would be to have two outlets close together and just tie a ground between the two.


builder3203 posts10-22-2019 6:26pmrobert, first, I’m not an electrician, so take anything I say with a grain of salt. That being said, I have been in residential construction for 30 years. I’m in the Pacific NW. I’ve never seen an electrician here use a metal box in a home without good reason. Something heavy, like a ceiling fan, or remodel work in an older home. I wouldn’t think audio AC cables would rise to that level, given a quality box like a Pass & Seymour, etc.I wouldn’t run a ground like you describe. An electrician may or may not, I’m not sure. Generally, from my limited understanding, it’s not advisable to just bond grounds together at random. I’d have two separate circuits, or only one. 

Why not just have one circuit? There’s no load to speak of. A single run of 12 wire and whatever outlets and box you care to use should be more than adequate.
On a separate note (and run this by a real electrician), I’m wondering if there’s any reason you’d be prohibited from having the two separate circuits, but only use one of the grounds for both. Leave the second ground unused in the back of the box. May be reasonable, may not be, talk to a pro.

Big power amps with linear supplies can draw peak currents off the AC line in the 10's of amps. Depending on the gauge of your run, even with 12 awg, that can lead to significant voltage drop and essentially modulates your AC line which leads to distortion products that are a function of 1x line frequency, 2x line frequency, and the frequency of the music. It all depends on how sensitive your equipment is to noise on the AC lines.


The problem will be which "pro". Both electricians and inspectors can run into knowledge gaps when you are doing something out of the ordinary. I have had to deal with that a few times.

Whether you can slide by a single ground wire would come down to the size of the breakers. Typically the ground wire must be equal to the size of the conductors, and since you have 2x conductors, you would need 2x ground wires of equal gauge or the breakers rated for less current than a single run of the ground wire. Better and safer to connect both.

builder3206 posts10-22-2019 9:07pmWhy not just have one circuit? There’s no load to speak of. A single run of 12 wire and whatever outlets and box you care to use should be more than adequate. 
On a separate note (and run this by a real electrician), I’m wondering if there’s any reason you’d be prohibited from having the two separate circuits, but only use one of the grounds for both. Leave the second ground unused in the back of the box. May be reasonable, may not be, talk to a pro.