Advice On Wires For Studio

[Starise]

Wiring standards and descriptions are different between countries. My question concerns the US wiring standards.

I'm finally getting around to pulling some wires for a future studio from an electrical sub panel I put in for another project. An electrician friend of mine mentioned there is a special high voltage wire (115 volts) I could get that comes with a shield to reduce interference into the line. It basically sounds like NM-B wire with an integral shield made into the wire that goes to neutral in the panel. Not an external conduit. Does anyone know what this wire the electrician is referring to is called?

I originally planned to run two 12-2 with ground NM-B wires 20 amps each.  I was thinking one for lighting and one for the computer and equipment. I won't be running a bunch of outboard hardware gear. Just a computer, interface, monitors, some keyboards and maybe a guitar effect or two. 20 amps is probably overkill. I already have the heat pump installed on a separate breaker. 

Edited May 21, 2020 by Starise

[DeeringAmps]

I don't know about shielded wire, so I can't comment (overkill?).
No good reason not to go with the 12-2 and 20amp outlets, IMHO.
This of course assumes you have at least 20 amp capacity at the sub panel (probably at least 50 amps per leg?)
I have heater/ac/lighting on one leg and computer/audio gear on the other; no issues.

tom

[Starise]

Hi Tom,

Yes this is a 50 amp sub panel  using 6 -2 with ground  wire coming from my 200 amp service. The breaker for that panel is actually in the 200 amp panel since the sub panel doesn't have the option for a main breaker. The sub panel has a 25 amp breaker for the heat pump and four  20 amp breakers all ran using 12 wire. Two of those breakers are in another location. One is only for a large ceiling fan that probably doesn't use over 5 amps. The other breaker is for outlets in another room where nothing more than a vacuum cleaner, reading light or  fan will ever be plugged in. The other two 20A breakers are designated for the studio. One for lighting and the other for gear.

Since I'm getting some low hum in my system now I was attempting to eliminate hum in the other studio. The hum I get now is likely from emissions coming off the wire or bad wires since I'm only on one circuit in there. There's a lot of spaghetti though and I think it shares the lighting.

A dedicated 20A should help. I looked around and the closest thing I could find non MC was something called "tray wire". They use it for electronic cash register runs and similar. It's also called instrumentation wire. That wire seems to have an aluminum shield.  Maybe the wire my electrician friend mentioned as actually some kind of special MC that lets you ground the jacket or has a wire fused to the outer jacket ? Still looking.

[craigb]

On a bit of a related side-topic, one of the best ways to wire things up in your studio (if you can) is to shield the audio cables in flexible aluminum conduit.

Then keep any electrical cable outside of this tubing.  Another approach that you will hear is to make sure that your power cables cross your audio cables at a 90 degree angle.  All of this is to help keep electrical interference out of your recordings and playing.

In a condo I used to own, I also did this in my main living room since that had my big screen and surround sound system.  If you look at the picture below, you'll (barely) see a flat piece of wood going up the room corner behind the TV which then joins with the crown molding that goes around the top corner between the walls and the ceiling.  Behind the crown molding you would find the exact setup I mentioned above: Audio cables inside flexible aluminum conduit with power cables outside the conduit.

[craigb]

Another shot showing the crown molding and one of the surround sound speakers.

[Starise]

Thanks Craig. Nice areas. You hid those wires well. I used to work with MC which is the external covering cable you showed. I still have the cutters for it. I much prefer buying the higher voltage type with the wire already in it. It's a real pain to fish wires though MC conduit. I might actually end up using that or something similar. From an electrical emissions standpoint I wonder how much it will help because the sub panel is  25 Ft. away in a closet located in another room. I could still have issues from the panel.

In doing a search for how studios are wired I mostly encountered the audio cable connections info and the notorious issues with ground loops. All important for sure. I don't tend to buy the most expensive cables for my audio gear. I would say it's mostly mid grade. You hear very little about the high voltage. I say high voltage relatively speaking because I've been around 13,800 volts. This is only 115 volts/120 volts. Still enough to bite you if you touch it. 

There's already a 220 volt line running in the attic above my future studio for the heat pump. It isn't shielded but it is grounded well. It wouldn't be  very close to my audio gear.  The other lines will come into the space from the attic area and down through the walls. I'm sure the unit outside is well grounded ( I installed it). Looks like lunch for a thunder storm though with all of those circuit boards in it . 

 

Edited May 22, 2020 by Starise