Electrical Circuits

Velvet Elvis

Velvet Elvis

Ahh humma humma humma
Ok... the time has come (YEAH!!!) for me to submit my building plans to the city permit office.

In doing so, I need to give a rough idea of my electrical configuration as well.

My question is this... assuming I have a sub panel in the studio (which I will), how should circuits be split up?

I've read that lights should be on their own circuit to improve noise issues, but what about the board/rack feed vs. the other control room outlets or the live room outlets?

In a live situation, you want all of your audio equipment to be pulling from the same circuit, and I would assume the same is dersirable in the studio, but I guess I don't know... hence my asking.

Velvet Elvis
 
IMHO everything should have its own circut, outlets, lighting ECT ( I mean one circut breaker per outlet, light fixture ECT.). imagine if all your equipment in the control room was all on the same circut and your live room was on another and you are recording and someone has a faulty amp and a circut breaker pops, there goes your session, if it is all seperated only two pieces of equipment will shut down and that is better than all... :)
 
Carter said:
IMHO everything should have its own circut, outlets, lighting ECT ( I mean one circut breaker per outlet, light fixture ECT.). imagine if all your equipment in the control room was all on the same circut and your live room was on another and you are recording and someone has a faulty amp and a circut breaker pops, there goes your session, if it is all seperated only two pieces of equipment will shut down and that is better than all... :)
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A couple of UPSs are a lot easier than a few dozen circuit breakers and the massive wiring that approach would require, plus they protect you from general power outages.

And maybe put a fuse on the amp?
 
The final configuration (electrical wise) is three circuits.

Circuit 1 (15A) all the lighting, flush and track, the web cam, the peripheral outlets for fans, space heaters, clocks, answering machines, and the 10/100 ethernet switch.

Circuit 2 (20A) anything connected by analog - all the mixers, the synths, guitar amps, outboards, etc.

Circuit 3 (20A) the two computers, the video monitors, and the large rack of Akai hard disk recorders (connected via toslink), and the akai remote, and the 10BT coax ethernet crap that Akai likes to use to sync it all together.

I have a small window A/C as a temporary solution, and that plugs into circuit 1. It draws 10A when it first kicks on, all the lighting combined draws 4A or thereabouts, so its close to the limit of the breaker but not exceeding it.

Circuit 1 feeds four switches, which switch and dim the various lights.

Circuit 2 feeds one switch, which in turn turns on all the gear all around the room. I used red wall plates to indicate "audio gear".

Circuit 3 feeds two switches, one turns on the primary PC, the two monitors, and the KVM switch, and the second switch turns on the secondary PC, all the hard disk recorders, etc, and is fed off the first switch.

I did this so I can use one PC without everything else being on, so I can surf the net, pay bills, etc. The second switch allows me to turn on the recorders (and the controller) before turning on the rest of the studio gear, as my wordclock generator is on the akai power feed.

You don't have to split it this far up, actually, incandescants on a straight switch can be integrated into the power feeding the audio equipment... its the flourescent lights and the dimmers that really need to be seperate. I chose to split it further.
 
frederic!! long time no talk buddy!

That's sort of the line I was thinking... three circuits, one for lighting, one for computers (although they will have an analog audio tie) and one for the rest of the studio equipment.

Do you think having a board, all the outboard gear, all the recorders PLUS the guitar amps and such will be too much for a single circuit though?

Velvet Elvis
 
Yes, long time no chat. Been enjoying the summer playing "car monkey", finishing up the mechanical's of the 600cid twin-turbo motor for my truck, as well as building a new bumper to bumper wiring harness so I can add all the options I want. Add to that low voltage wiring for outdoor lights around the pool and deck areas, rebuilding the motor on my riding mower (instead of buying a new one - darn they are expensive!), and remodeling not one, but two bathrooms. Next is to remodel a bedroom for a baby room, since apparently I have to :)

Anyway, the easiest way to determine if your circuit is large enough for what you want to use it for, is to add up all the wattage on the back of all the devices. Rack mount units typically have a 5-10W wall wart, some synths draw 50W, etc. Add it all up, then you know what the circuit needs to be.

Voltage * Amps = Watts.

120V * ?? = the sum of the watts of your equipment.

?? is the size of the switch 15A or 20A, as well as the breaker. If you need more than 15A on a circuit, nothing wrong with running the correct wire for 20A, and using a 20A breaker. Just make sure you use a 20A switch, rather than a 15A switch. All switches are clearly marked. VERY easy mistake to make even for professionals.

Having your computers on a seperate feed is fine, however its possible to get hum, you might want to try it with extension cords into two different breakers, to see if you have hum or not. I did, which is why I updated to a digital sound card that has toslink in and out for stereo or 5.1 sound. Optical cabling is what isolates the computer on one circuit, from the boards on another circuit. I'm using digital mixers... so s/pedif and aes/ebu was avaialble, just had to convert it to optical.

This is also why I can get away with having my akai recorders "way over there" and on a seperate circuit from the console... using toslink there as well. Made my own toslink cables using glass fiber isntead of plastic, so I can run the fiber optic cable a longer distance.
 
A baby frederic on the way!?! Wow... congrats man!

Being that I'm somewhat of an analog guy, I have all analog connections between my records and board etc... so I want to make sure to minimize the noise.

I was planning on using the low voltage lighting systems as well... however I assume that their transformers can be noise makers just like the ballasts on flourescents.

Velvet Elvis
 
The things that make the most noise are motors and ballasts. But the ballasts on compact fluorescents do not make the same kind of noise.

But beyond that a panel and circuit breaker does not stop noise. For that you need filters and power conditioners. UPSs also have the function of conditioning power, but your best results is going for something specifically for that job, like from Furman.
 
A baby frederic on the way!?! Wow... congrats man!
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Thanks!

Being that I'm somewhat of an analog guy, I have all analog connections between my records and board etc... so I want to make sure to minimize the noise.
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There are filtering breakers, as well as isolation transformers that you put into the circuit, that significantly reduce hum.

I was planning on using the low voltage lighting systems as well... however I assume that their transformers can be noise makers just like the ballasts on flourescents.
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Low voltage transformers make very little noise as compared to flourescents, actually. Its essentially a giant wall wart.
 
Look at my post here:
https://homerecording.com/bbs/showthread.php?t=67339&highlight=Electrical
We talked about this in depth.
Be sure to scroll down to my SECOND post in that thread to see the breakdown.
I think I came up with 130 watts total.
The One Outlet - One Breaker, One Switch - One Breaker is NOT going to fly!
No. 1) NEC and UEC requires one electrical outlet every 10 feet (Or something close to that) So you'll end up wit a lot of outlets.
No. 2) You'll end up with a lot of switches too.
No. 3) Its not cost effective.
No. 4) Its over kill that you don't need. Would you put a street lamp on your back porch? (I mean.... any one besides frederic?) :D

What you'll need to do is break it down into zones. You can do all the planning you want, but when your electrical contractor pulls the actual work permit, he's going to do the minimum requirement to bring it to code and pass inspection.

Probably the most important thing to convey to your contractor is to have your control room outlets star grounded. What that means is that each outlet gets a dedicated run all the way back to the pannel. Its expensive, but the only way to do it right.
You'll also need GFI's near any wet surface, AND you'll HAVE to have a smoke alarm that's hard wired into the main pannel. (One of those peel and stick-battery operated jobs WILL NOT cut it for new construction)

frederic - Long time no see! Hope things are going well. Here in Austin we have a local amendment to the NEC, and it states specifically no 15A circuit breakers may be used. I don't think you can even buy a 15A breaker here.
I think its just to avoid confusion in the wiring. If I'm not mistaken, a 15A CB would require a 14/2 romex. But 14/2 is inadequate for a 20A breaker; that would require 12/2 wiring.
So you could see how that 14/2 MIGHT get accidently hooked up to a 20A breaker. If that happened, the wire would probably blow before the breaker.
 
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Michael Jones said:
Be sure to scroll down to my SECOND post in that thread to see the breakdown.
I think I came up with 130 watts total.
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I think you mean amps here, and you were building a separate structure, no?

In a basement studio 20A for all the gear should be enough, unless you are blasting lots of guitar amps or something. The big two in the rack are the power amp and the PC, say 600W for the power amp and 400W for the PC, that still leaves 1400W for the other gear which really doesn't consume much power. Heck half that stuff probably runs off of wall warts.

If you have a big rack, then maybe separate circuits for the rack & the other outlets (and of course lights).

Probably the most important thing to convey to your contractor is to have your control room outlets star grounded. What that means is that each outlet gets a dedicated run all the way back to the pannel. Its expensive, but the only way to do it right.
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You can trace them all back to a single box, and wire that box back to the panel. You just have to avoid wiring through other boxes with outlets.
 
Something thing no-one mentioned,

Things like fans - compressors (etc) can (in the US) transmit a 60 cycle (different cycles in other countries - but same theory) hum through the leg of the panel they draw from.....

It's a good idea to put the circuit from them on one leg of the panel and your sound gear (and subsequent curcuits) on the opposite legs.

BTW, Star grounded (hospital) receptacles are a great idea - but I install them in both the control room and tracking rooms.

Rod
 
mshilarious said:
I think you mean amps here, and you were building a separate structure, no?
Yeah, I meant amps. What did I say? Watts? Just shoot me now. And yes, I was building a separate structure, so I had to contend with HVAC, a grinder pump, and a kitchen (refridgerator).

In a basement studio 20A for all the gear should be enough, unless you are blasting lots of guitar amps or something. The big two in the rack are the power amp and the PC, say 600W for the power amp and 400W for the PC, that still leaves 1400W for the other gear which really doesn't consume much power. Heck half that stuff probably runs off of wall warts.

If you have a big rack, then maybe separate circuits for the rack & the other outlets (and of course lights).
Wouldn't hurt to have a licensed electrician provide some input, or an electrical engineer

You can trace them all back to a single box, and wire that box back to the panel. You just have to avoid wiring through other boxes with outlets.
I guess it depends on the local amendments to the code that's being enforced
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As always, check local codes, or better yet, hire a professional.
 
Carter said:
IMHO everything should have its own circut, outlets, lighting ECT ( I mean one circut breaker per outlet, light fixture ECT.). imagine if all your equipment in the control room was all on the same circut and your live room was on another and you are recording and someone has a faulty amp and a circut breaker pops, there goes your session, if it is all seperated only two pieces of equipment will shut down and that is better than all... :)
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Nonsense.

Do everybody here a favor and withhold dispensing advice on questions involving electrical work. You don't have the first clue what you're talking about.
 
I truly appreciate the advice guys... I'm soon to be "licensed" for home electrical work by the city, so I will by doing all of the basic installation myself... they just want to know what I plan on doing.

I was planning definitely on doing the star-ground.

My basement has a subpanel (not yet installed)... when they built my house, they put my breaker box on the OUTSIDE WALL of my garage... I have no way to get wires there... so knowing they had done this, I had to pay through the nose to have them drop a line for a subpanel in the basement, which is not yet installed.

I have no idea how the subpanels work... IE - if I can chose the leg that various breakers go on. I would assume I can, but I've never dealt with a subpanel.

If everything has a star ground back to the breaker box main ground, does having analog devices on different circuits matter as much? I don't want an artist getting shocked because his amp is on one circuit and the preamp for the mic he is singing into is on another (granted he shouldn't be putting his face on my mic!).

I appreciate all the info!

Velvet Elvis
 
Electrical Installation Help

Hello Velvet Elvis, Frederic and all who are contributing to this current post :rolleyes:

I'd like to offer some help.... ;)

I'm a Licensed Electrical Inspector for the City of Philadelphia (28 years)

Perhaps your municipality requires you to hire a LICENSED Electrical Contractor?

You mentioned that you can perform some of the basic work yourself?

In any event, unless you already have a reliable person in mind, be very careful that you retain someone who is competent, licensed, and will listen to your requests, and requirements in regard to the wiring of your studio .....
Perhaps you can ask him for credentials ;)

That being said, let me make a few points:

I agree that the new low voltage lighting systems are nice - and they won't emit as much noise as conventional ballasts ....

But check your varieties of fixtures - some tend not to produce as much light output (Lumens) as conventional incandesant lighting ...

Someone said that 15 amp overcurrent devices (breakers), and no. 14 wire are not allowed or available in their area?

Well - 15 amp breakers, and number 14 wire (14/2 romex), are actually quite practical for lighting :) And perfectly legal as per the NEC (Nat'l Electrical Code) - That is unless the authority having jurisdiction as per the NEC overrules it's use.

Hard wired smoke detectors are a great way to go - they are required by the NFPA (Fire Code), in bedrooms of new construction.

Did someone mention insulated grounded circuits for receptacles?
(separated ground and neutral connections on your special receptacles)
Perhaps they were described as 'star grounds'?

Well that's a great way to go too - but your contractor should know to use 12/3, not 12/2 for the wiring of the receptacles.

The idea of the separate ground and neutral connection as someone pointed out, is to virtually minimize line interference - most folks are using this type of receptacle wiring for their computers. But major club venues, and studios are incorporating it more and more :D

It's a good idea to plan on few 20 amp circuits for equipment:
Perhaps computers on one circuit
Guitar amps on another
Lighting on a separate 15 amp circuit, and so on......

As Frederic pointed out, analog equipment usually draws more amperage than solid state stuff .. but I'd be more concerned with analog tube guitar amplifiers - they burn up lots - and one way to find out how many circuits you may need (to clarify Frederic's comments), is to check the power consumption on the amp spec tag. If it's rated in watts, then add up all the individual loads and divide the total by 120 (volts)

For example if you have 3 guitar tube amps, and a rehearsal PA that total about 1000 watts, the total consumption is 8.3 amps....
The NEC states that a continuous load should be only 80% of the ampacity of the circuit. So one 20 amp circuit should only see about 9.6 amps. In the case above, another 20 amp circuit would be a good idea ... capish? understand? :cool:

When all is said and done, (depending upon the studio size), an average might be about 2 or 3 power circuits for receptacles, 1 or 2 for lighting, and 1 or 2 for computers...

Hopefully your panel will accommodate this space?

Feel free to provide me with more info in regard to your set-up ;)

Best Regards
Michael Fraticelli
ROCKON@ucwphilly.rr.com
 
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ENIGMACODE said:
Perhaps your municipality requires you to hire a LICENSED Electrical Contractor?
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This'll probably scare you, but I live in a very large jurisdiction & as a homeowner I can do anything I want--electrical, HVAC, plumbing, carpentry--I have to pass inspection of course. I've run a couple of circuits, but just simple stuff like a single outlet circuit for a window AC and another for the garage . . . anything complicated I'd still sub out.

For plumbing I am completely useless. And let's not talk about carpentry . . . although I'm pretty good at building fences.

The NEC states that a continuous load should be only 80% of the ampacity of the circuit. So one 20 amp circuit should only see about 9.6 amps. In the case above, another 20 amp circuit would be a good idea ... capish? understand?
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Sorry, I don't! I don't get the math. What is the difference between the rating and ampacity? In other words why isn't it 16 amps? What about a bathroom where you've gotta turn on your 1875 watt hair dryer?
 
Not... I'm not required to have a licensed electrical contractor... only that I pass the city's electrical code test.

Everything I'm doing is legit and above table... I'm making sure of that.

Velvet Elvis
 
Um......... yeah. 80% of 20a = 16amps.

16a x 120v= 1920watts.

I don't know if you can buy a single-phase sub-panel. I've never seen one.

Usually, a subpanel in a house is fed with 120/240, behind a 2-pole breaker that corresponds to the ampacity rating of the subpanel. What size wire did they run for your subfeeder, and how long is the run in length? Also what type wire. It's marked on the jacket.
 
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c7...

I will find out for you tomorrow... I'm trying to write out some chord charts for some people tonight, so I can't go dig around in the basement :)

Thanks for the help man!

Velvet Elvis
 
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