Wiring Of Live / Drum / Control Rooms

[trunkdog]

Greets!

Would any kind soul like to offer their unbinding opinion on running the electrical wiring circuits for my studio here in the USofA?

I have:
Live Room (500 ft²)
Drum Room (216 ft²)
Control Room (216 ft²)

I intend to run isolated ground circuits of no more than six receptacles per circuit in each the live, drum and control rooms. Receptacles will be color coded.

All will be "home run" circuits

I intend to use 12/2 with iso ground MC cable for the receptacles. All receptacles for audio equipment use will be on separate circuits from those dedicated to non-audio use; lamps and such. The non-audio circuits will also be ran using the 12/2 IG MC cable.

I intend to use 14/2 and 14/3 MC cable for the lighting circuits. The lighting will be a combination of T12 electronic ballasts (Noise Rated Type A) and LED fixtures.

I further intend to separate / isolate the runs for the 12/2 IG MC of audio wiring from the non-audio wiring.

All the above in an effort to minimize hum.
I will eventually replace the T12 bulbs with LED.

I also intend to run CAT6 shielded riser networking in all rooms with drops for each musicians in the Live Room. I am allowing for AVB and Radial Catapult.

My questions are:
Does the 12/2 IG MC make sense?
Does isolating the runs make sense?
Opinions on CAT6 vs CAT6A vs CAT7
Should I plan on running any XLR cabling to the Control Room (aka snake / patch bay)?
Anything I'm overlooking?

Thanks in advance for any and all guidance / assistance / admonitions / condolences.

[cashhewn]

Sounds fun! But I wouldn't want to do it again yuk yuk etc

I'm sure once our British friends have risen there will be lots of great info from the usual suspects, but in the meantime I can speak to this:

Does isolating the runs make sense?

Please forgive me if you already know most all of this...

In my experience, it makes good sense. My wife in her art studio next door that shares the same mains leg from the street and same breaker panel, can run her various saws and vacuums and photography lighting etc etc and all of my isolated audio gear remains at what I consider a whisper quiet noise floor.

As far as isolation, what I did and would strongly recommend, is putting downstream of the "house power" circuit panel, an isolation transformer, that then feeds a "tech power" circuit panel, and I would even put those home run tech circuits/receptacles on 20 amp breakers, because why not. I have loads of valve/tube outboard and guitar amplifiers etc etc and have never had any issues with sag etc. In fact my entire analog console and its power supply and all of my outboard and my mains monitors etc etc (if I recall correctly) are on one 20A quad receptacle (actually maybe two now that I think about it).

I used a 25 kVa isolation transformer with a 240V input that steps down and supplies 120V/208A out (it has a weather kit and it sits outside the studio on a little pad year-round).

I would put in line with this isolation transformer a "lightning strike" rated surge protection/absorber to protect everything downstream of it on the "tech power" leg. Mine also sits outside but wall mounted next to the breaker panel. I also purchased a mains shunt trip breaker to wire into the tech panel that was supposed to throw a mechanical relay to even further isolate the tech power circuit in case of trouble, but my electrician told me that he "couldn't figure out how to wire it up" and so that was a couple hundred down the drain...

Lastly, even with all of this, you are still susceptible to ground loop buzz/hum, of which I experienced a lot of when first getting up and running, and at first thought I had wasted all of my time and effort on isolation before I understood the problem of ground loops, and after many hours and days chasing down various loops as I was adding more and more outboard, finally reduced all of those back to whisper quiet operation. But ground loops can be frustrating, especially as you're just getting up and running: they have to be scientifically/methodically chased and eliminated.

That's off of the top of my head. Have fun! What a time to be alive!

[James Perrett]

Sounds fun! But I wouldn't want to do it again yuk yuk etc

I'm sure once our British friends have risen there will be lots of great info from the usual suspects, but in the meantime I can speak to this:

Unfortunately UK and US wiring conventions are so different that we won't be much help. The UK uses a higher voltage which could be more dangerous but it also means that currents are lower.

Mains isolation is rarely needed in the UK unless you are on a building site and using it for safety reasons.

[trunkdog]

Sounds fun! But I wouldn't want to do it again yuk yuk etc

I'm sure once our British friends have risen there will be lots of great info from the usual suspects, but in the meantime I can speak to this:

Does isolating the runs make sense?

Please forgive me if you already know most all of this...

<<snipped>>

That's off of the top of my head. Have fun! What a time to be alive!

Thx for the response and highlighting the obvious flaw in my post; I completely neglected to address the "power conditioning" aspect as my main focus was on ordering materials for the circuits. I do intend to provide power conditioning "in the building" and actually gave no thought to isolation at the incoming source. The other half of my studio is dedicated to my wife's sewing and embroidery shop. So, apart from the questions I've raised I also have that aspect to consider.

Surely there's an ai app to address all this

I'll search here for "ground loop" etc.

[trunkdog]

Sounds fun! But I wouldn't want to do it again yuk yuk etc

I'm sure once our British friends have risen there will be lots of great info from the usual suspects, but in the meantime I can speak to this:

Unfortunately UK and US wiring conventions are so different that we won't be much help. The UK uses a higher voltage which could be more dangerous but it also means that currents are lower.

Mains isolation is rarely needed in the UK unless you are on a building site and using it for safety reasons.

Thx JP, I've oft wondered how we in the Land of the Free got the whole voltage thing "wrong"; safety I assume.

[trunkdog]

Just ran across this gem:

https://www.soundonsound.com/sound-advi ... os-podcast

[trunkdog]

Just to help clear things up in my mind, as if that's even possible… for the isolated ground receptacles using MC cable, the metal clad or armored cable provides me shielding (EMI / RF) for noise reduction. The isolated ground cable / receptacles eliminates or minimizes the possibility of objectionable current. Or to put it more plainly; the jacket for shielding, the extra (iso) ground wire for objectionable current?

At any rate, I've now got all the components in house and will begin the wiring this week!

[James Perrett]

Just to help clear things up in my mind, as if that's even possible… for the isolated ground receptacles using MC cable, the metal clad or armored cable provides me shielding (EMI / RF) for noise reduction. The isolated ground cable / receptacles eliminates or minimizes the possibility of objectionable current. Or to put it more plainly; the jacket for shielding, the extra (iso) ground wire for objectionable current?

At any rate, I've now got all the components in house and will begin the wiring this week!

You must have some pretty dodgy gear if you need screening on the power cable. Or do you live next door to a powerful AM radio transmitter? And what actually is an isolated ground? Surely a ground is a ground?

This all sounds really weird to someone used to UK power wiring but I know that US wiring is totally different to the way we do things here.

[trunkdog]

Thx for the input, JP. I'm just learning as I go, trying not to do too many foolish tricks while trying to avoid the myths that permeate all things earthing / grounding. I will no doubt have made many errors after completion but none should prove hazardous as I am erring on the side of safety in the final choices. Simply put my grasp of the earthing goes like this:

Unshielded AC cable will act as an antenna, picking up undesirable noise. Minimize this by "shielding" the wires, hence Metal Clad or MC cables in use. For AC receptacles powering "delicate or sensitive" gear; provide a separate "equipment ground" hence the "isolated ground". This "iso ground" serves to carry any "objectionable current" that has potential on the ground.

The more I read on the subject the cloudier it becomes; with some "experts" going so far as to say one defeats the earthing (noise) benefits by going this route. If the geniuses continue to argue the merits, who am I to bring light to the subject. At the end of the day I just want my studio wired as cost effectively and efficiently as this untrained layman can accomplish.

[James Perrett]

Everything you say sounds really weird to me. There should be no such thing as an isolated ground in your studio and screened power cables should never be needed (unless you are an audiophile with more money than sense). There may be a need for separate clean and dirty power circuits if you have large items of machinery but for general electronics and lights one circuit should be fine.

Of course signal cables are a different matter but I understand that we are talking power cables here. Given the level of confusion, it may be best to talk to a reputable electrician - or at least consult a US based forum where the mysteries of US power wiring may be better understood.

[Hugh Robjohns]

Unshielded AC cable will act as an antenna, picking up undesirable noise.

From where? And at what level?

In the UK individual mains (line/neutral/ground) wires are sometimes run in metal conduit, but usually for mechanical protection rather than screening.

I have no screened mains cable runs anywhere inside my house or studio... and I have no mains noise issues at all.

There's no theoretical problem using screened mains cables if you want, though... but it must be an expensive option and probably tougher to install... and for zero benefit in all liklihood.

For AC receptacles powering "delicate or sensitive" gear; provide a separate "equipment ground" hence the "isolated ground". This "iso ground" serves to carry any "objectionable current" that has potential on the ground.

This is where I start to get really squidgy... I'm more comfortable with the idea that everything is earthed back to one common point. Having completely separate ground references in the same space could, under some circumstances, cause real problems.

By all means have separate mains spurs for technical equipment and noisy gear like HVAC, elevators, etc... but they should all be earthed back to the same point.

But I've no idea what US code regulations allow so my best advice must therefore be to consult with a qualified local electrician, and ideally one with studio build experience.

[Watchmaker]

do not run 12/2! run 12/3 for receptacles (code).

Also, since you obviously (no offense) don't know what you are doing re: electrical, talk to a pro. I'm US based and currently own a construction company. I have decades experience in building. You can PM for stateside advice (unbinding)

*edit* I had to post the above before reading answers...UK folks, Gawd bless 'em, will not be able to advise. Not only do they have different circuit philosophies, they also use a different language from us.

Please do not try to do electrical alone. Also, the overwhelming majority of what you're after isn't really an issue unless it presents in your specfic circumstance. Don't assume you have dirt power, don't worry about mains being dirty unless you have a reason to.

Most US power is pretty clean and ground means exactly that. Earth your power to earth. Literally. Everything should be, as Hugh points out, tied to a central ground, unless you have a very specific reason otherwise. As for MC cable, the sheathing is to protect against damage for exposed cable runs. It does nothing related to power transmission, provides zero "sheilding" from EMI/RFI afaik. If you have the romex in the wall or under the floor, you won't need the metal sheathing.

I use my 120V house line conditioned through an uninterruptible power supply to a couple of Furman power conditioners. I can run my whole studio, including PA from one 20 amp circuit. I have never had an issue related to power that wasn't my own fault in wiring AFTER the outlet.

Don't over think it, build to code. https://codes.iccsafe.org/content/IRC20 ... electrical

[trunkdog]

Thx for the response watchmaker. No offense taken. You mean to tell me 12/2 with ground isn't to code?