I think its overkill, but you should have lights on a different branch circuit.

Are the lights and HVAC on different breakers?
Hope so.

How do you plan on running your grounds?
Here is a good picture of a star (or medical) grounding method:

http://members.ozemail.com.au/~tabbler/GndRule/GndM06.html

This will help clean up a lot of potentional noise issues.

Breaking the load on different breakers doesn't hurt. I had 5 seperate breakers for my last studio and it worked out well. 3 for the live room and two for the control room.

oops

Are the lights and HVAC on different breakers?

The house has no AC, but my audio equipment will certainly be on different breakers than the lights and furnace.

How do you plan on running your grounds?

Question of the day!! I just went downstairs to check out the main breaker panel in the house and found there is one twisted copper ground wire attatched to a water pipe and another that goes out through the wall and outside somewhere. I've been running my studio equipment upstairs in this house for about a year now and have never had any noise/grounding issues. Therefore I assumed I could take advantage of the extra slots on my panel, pop in a few new breakers and wire the outlets up as one normally would in a home. This house has a (HUGE)200A panel, as well as a sub panel. Should I be worried about grounding differently?

Thanks for the advice - keep it comin

The ground wire running to the copper water pipe (or galvanized depending on the age of the house) is considered the main bonding jumper for your system. It originates in the water meter main at the street and presents a few feet of direct contact with earth in its passage to the entrance into the house. Hopefully 20' or more. The other copper wire which goes outside to an unknown destination is most likely to a ground rod. It is considered a supplemental ground. Its also the reason you wont have grounding noise issues.

All power to your studio should be on the same phase in the panel. If you are installing the breakers on the same side of the panel, this would be every OTHER slot. ie: 1=a, 2=a, 3=b,4=b,5=a etcetc..reading from left to right of course.

is it overkill? Most definately.

Its simple. 1500 watts divided by 120 volts equals 12.5 amps. Legally, you can load a breaker to 80% of its nameplate rating, so 1500 watts is a bit over what you should put on a 15 amp breaker, though this is NOT outside of a safe installation, it is simply the electrical code.

Remember this. A breaker is protecting the wire, not the equipment. The equipment is the demand on the circuit.

If you wire your room with this in mind, you cannot go wrong.

If you DO NOT put everything on the same side of the phase, you risk a hazard of a different potential between pieces of equipment on different phases. The potential for noise is only a small part of this hazard....the chance of you getting 240volts across your heart while dinking around behind the rack has a much more permanent and unwanted effect than a little buzz could ever have.

Please be neat and tidy with your install. Proper strip lengths on the wires, no crowding of devices and too much wire in the boxes, no short wires to devices in the boxes!!! (theres a happy and safe medium there) Use commercial grade devices. DO NOT use the quik-wire terminals on the devices.....use the screw terminals or if you spend a bit more and go a bit higher grade , you will have lugs instead of wrapping the wire on the screw terminals. Much better. I use hospital grade devices on everything. The ground wire is isolated from the mounting strap on each plug and it allows for a redundant ground to you boxes if you are using metal.

Too much? Its why you hire a pro.

Davedog wrote: The ground wire running to the copper water pipe (or galvanized depending on the age of the house) is considered the main bonding jumper for your system. It originates in the water meter main at the street and presents a few feet of direct contact with earth in its passage to the entrance into the house. Hopefully 20' or more. The other copper wire which goes outside to an unknown destination is most likely to a ground rod. It is considered a supplemental ground. Its also the reason you wont have grounding noise issues.

All power to your studio should be on the same phase in the panel. If you are installing the breakers on the same side of the panel, this would be every OTHER slot. ie: 1=a, 2=a, 3=b,4=b,5=a etcetc..reading from left to right of course.

is it overkill? Most definately.

Its simple. 1500 watts divided by 120 volts equals 12.5 amps. Legally, you can load a breaker to 80% of its nameplate rating, so 1500 watts is a bit over what you should put on a 15 amp breaker, though this is NOT outside of a safe installation, it is simply the electrical code.

Remember this. A breaker is protecting the wire, not the equipment. The equipment is the demand on the circuit.

If you wire your room with this in mind, you cannot go wrong.

If you DO NOT put everything on the same side of the phase, you risk a hazard of a different potential between pieces of equipment on different phases. The potential for noise is only a small part of this hazard....the chance of you getting 240volts across your heart while dinking around behind the rack has a much more permanent and unwanted effect than a little buzz could ever have.

Please be neat and tidy with your install. Proper strip lengths on the wires, no crowding of devices and too much wire in the boxes, no short wires to devices in the boxes!!! (theres a happy and safe medium there) Use commercial grade devices. DO NOT use the quik-wire terminals on the devices.....use the screw terminals or if you spend a bit more and go a bit higher grade , you will have lugs instead of wrapping the wire on the screw terminals. Much better. I use hospital grade devices on everything. The ground wire is isolated from the mounting strap on each plug and it allows for a redundant ground to you boxes if you are using metal.

Too much? Its why you hire a pro.

Depending on the age of the house, and how it's framed (wood, or block) the ground rod should be in the slab of the house, usually in the garage and there's a blank plate over the acorn clamp holding the bare copper to the ground rod. Block houses however have it outside the slab of the house actually in the gorund rather than the concrete slab. At least that's code here in Florida.

I am a residential electrician and I just wanted to emphasize on what dave said about making sure wires are stripped out to proper lengths etc. You can create all kinds of problems if you strip out too much...especially if you use the quick-wire terminals too which as Dave said DON'T use in this application.

also are you putting your studio stuff on a 15A or 20A circuit?

A grounding element in a slab is known as a U-fer ground and should be a 20' uninterrupted piece of 5/8' or larger rebar. This is either in the slab or in the footings IF the footing has a direct contact with earth.

Though there are local differences in code, the ones I'm am talking about are national code, and even though he is in Canada, they also adopt a code very similar to the American code.

In my part of the country we are required to drive two 8'X5/8" galvanized ground rods as supplemental grounds due to the soil conditions . This assures that the impedance of the ground will be under .4ohms throughout the system.

Unlike talent, the measure of this 'potential' is not something you want to encounter.

I came across this interesting thread while planning the wiring for the composition studio I'm building. I could have started a new thread, I suppose, but the information already given here is relevant, so I thought I would add on to it. Hope that's ok.

The build is a retrofit in a previously finished basement in my residence. I'm having a sub-panel installed, which will be connected to a 30A feed from the main panel. The circuits will be isolated ground type using IG 12/2 AC90 cable. Only the studio receptacles will run off the sub-panel. The lighting and HVAC power will continue to run off the main panel, as prior to the retrofit.

I'm hiring a licensed electrician to install the feed to the sub-panel, but will wire the circuits myself. I'm technically knowledgeable and have wired the electrical panels for two previous studios I've built.

So here's the question I'm struggling with:

Davedog, post: 246136 wrote: All power to your studio should be on the same phase in the panel. If you are installing the breakers on the same side of the panel, this would be every OTHER slot. ie: 1=a, 2=a, 3=b,4=b,5=a etcetc..reading from left to right of course.

Davedog, post: 246136 wrote: If you DO NOT put everything on the same side of the phase, you risk a hazard of a different potential between pieces of equipment on different phases. The potential for noise is only a small part of this hazard....the chance of you getting 240volts across your heart while dinking around behind the rack has a much more permanent and unwanted effect than a little buzz could ever have.

If you would be so kind then, Davedog, to please follow my thinking:-

I realize it might simply be a difference in jargon, but as I understand the research I've done, with rare exceptions in the U.S. (and none in Canada that I'm aware of, which is where I live), all modern residential house wiring is single phase. Both legs of the 240V power coming into the panel are at 0 deg with respect to each other, i.e., there is no phase difference between them, the bus bars or the breakers connected to them.

To reiterate, I understand it may just be parlance, but when you say "on the same phase" and "on the same side of the phase", can I assume you mean the same 120V power leg of the 240V?

That said, again as I understand it, one should not put all of the studio circuits on the same leg by themselves, not because of phase issues, but because it will unbalance the power, and therefore the relative current that flows in each leg.

I can readily see how this current difference might lead to the hazards you are describing. That is why, as far as I know, if one decides to put all studio circuits on one leg it is necessary to balance the opposing leg with other non-studio circuits. The current draw must be balanced between the two legs.

I'm not trying to be troublesome here. As you've pointed out, these issues are critical, not only for audio performance but for safety.

I may very well be missing something in what you've said. To be honest, I don't see the problem with balancing my studio circuits across both legs of the sub-panel (the main panel which feeds it is already balanced).

Believe me, I do not underestimate the seriousness or hazardous nature of electrical work. And I am consulting a local professional. I would appreciate it very much if you would clear up my misunderstanding of this issue.

Thanks in advance, and kind regards.:)

- Wayne

Just wanted to offer an update, for any readers who might be unclear on the phase issue, as I was. My electrician was here this morning, wiring the sub-panel, so I asked him to explain.

He told me the two 120V legs of the 240V line are indeed 180 degrees out of phase, so when one leg is +120V, the other is -120V. However, that is not what "180 degrees out of phase" actually means (hence the distinction between phase and polarity) and (in the case we are discussing) we are working with a single phase system, so I did some further research.

I found a forum frequented almost entirely by licensed electricians, and the thread discussing this conundrum was a diatribe, to say the least. I don't see any explicit rule about posting links to other forums, so here it is:

[="http://www.electriciantalk.com/f30/120v-240v-residential-180-out-phase-7596/index4/"]120v /240v residential 180° out of phase - Page 4 - Electrician Talk - Professional Electrical Contractors Forum[/]="http://www.electric…"]120v /240v residential 180° out of phase - Page 4 - Electrician Talk - Professional Electrical Contractors Forum[/]

See posts #65 and #66 for a succinct explanation. Also that same fellows earlier post #48.

Here's another link to the same discussion, this time among engineers:

[[url=http://="http://forums.mikeh…"]Battle of the Phases[/]="http://forums.mikeh…"]Battle of the Phases[/]

In short, the 240V is supplied from a single transformer with a center tap, which is single phase by definition. As expected, when measured from the center tap (120V) the ends are positive and negative. This is polarity, not phase. There's no phase shift.

Another way of looking at it is that in order for the two 120V legs to add up to 240V, they must be in phase. If they were 180 degrees out of phase, they would cancel resulting in zero volts.

That said, from a particular engineering point of view, it appears that two voltages opposite in sign can be said to be 180 degrees out of phase. As an audio guy, I don't really understand this. I do think it's a matter of mathematical semantics though.

The argument involving current in the neutral as a result of unbalancing the two legs, however, still holds, I believe. Any more informed opinions on this aspect would be welcome, I think (not being the OP). Certainly, we would all like to know what we're dealing with when wiring up our studios.

Overall, I think I'm quite a bit clearer on the subject now, but I don't feel too bad, since even experienced electricians and highly educated electrical engineers seem to disagree on the nomenclature.:)

Cheers,

-Wayne

Hmmmm... I actually thought this was pretty straight forward... as I was taught this about 32 years ago.

Glad to see our education system is getting so much better!!

Hey MadMax,

I still don't have an answer to my basic question: Why should you put all your audio circuits on the same leg, and what about the balance issue?

How critical is it?

Since you have 32 years of experience, with all respect, I would be grateful if you would offer your thoughts.

Here is the original quote I'm having a problem understanding (so you don't have to scan the entire thread again):

Originally Posted by Davedog

If you DO NOT put everything on the same side of the phase, you risk a hazard of a different potential between pieces of equipment on different phases. The potential for noise is only a small part of this hazard....the chance of you getting 240volts across your heart while dinking around behind the rack has a much more permanent and unwanted effect than a little buzz could ever have.

I guess my quick response to Davedog's first statement would be "that's what the Neutral is for", and to his second statement, "as far as I know, the only way to get 240V through your body is to touch both live wire ends at the same time, so the best solution, I believe, is to shut the appropriate breakers off before you start 'dinking' around behind the rack."

I'm honestly not trying to ruffle feathers here. I'd just like some clarification, if you would be so kind.:)

Thanks,

-Wayne

The generally "accepted" reason for putting everything on the same phase is so simple, it's complex to explain, but what the hell... I'll give it a go.

Let's start with transformer inductance, since we're well passed Ohm's law...

As voltage rises through a wire, there is a magnetic line of flux that gets generated. As voltages fall, those line of magnetic flux collapes around the wire. (Are we good so far?)

That collapsing energy, when intersecting at the same angle, another piece of wire, that energey from the first wire, is transfered to the second wire. However, it will be exactly in the opposite direction. (Still with me?) Let's call that 180 degrees out of phase. (And where people just go wooby stoopid in single phase energy circuits. 3 Phase, everyone seems to get... but simple stuff gets complex, I guess.)

Just as a side note; If that collapsing field is perfectly perpendicular to the line of flux, you get a phase rotation of 90 degrees (90') (I know, boring right?)

OK, so when you are powering lots of different devices, (who's primary objective, is to amplify voltage signals), they all have power supplies, inductors and capacitors... (at least in their power supplies.)

"So...What does that do?"

Well, think about it... if all of your devices are converting energy into audio, it would be a bit more than prudent to be sure that they were all converting the same energy at the get go, no?!?

To achieve 240VAC, you have a single phase of energy coming into the power transformer that feeds your house. That energy is converted from couple hundred volts down to two legs of 120VAC at the transformer. (That "center tap to ground" job on the pole outside.)

While the energy is a single phase, it is indeed opposite polarity to center tap. If you were to put a scope on the two legs of the secondary, you would see them as exact opposites of each other, and thus "out of phase with respect to each other". (Pay attention to the ground wire now)

That CENTER TAP is what establishes what the highest voltage will be in relation to the widings on the transformer's secondary widing.

If a secondary winding is litterlly 300 turns of wire, then it should be exactly 150 turns to the center of the winding - to the center tap point.

If that winding is perfectly wound, then it doesn't matter which leg you tie to, either one would be 120 VAC.... in theory. (Reality is that they're usually pretty damn close... close enough, for most things anyway.)

However, since this isn't a perfect world, the practicality just dictates the prudence of using one leg for all your gear.

Now, onward...

There's a curious thing that happens in this world... I like to refer to it as reality.

Just as when you get a bunch of people together and give them a substantial amount of stimulant, beer is one of my preferred methods to illustrate... so, if I might be allowed?

People start to yak, and drink and socialise, and drink a bit more... and then a bit more... and just when the peak of flirtin' with the hotty next to you comes along... you gotta hit the head and ease some tension on your kidneys.... WHEW!!! Man... MUCH better!! Now you can go back to yakkin' up said previous conquest...

Well... things like lamps, toasters, microwaves, motors, compressors and the like, are all kinda' like our beer bash above. Whether that relief comes in the form of heat, reverse current, fluctuating current use, instantaneous surges, temporary voltage sags, etc... All that energy "noise" is gonna happen in that crowd in the room.

The room is the polarity "phase" of our story, and heat, surges, spikes and noise is the excess beer in our kidneys. It's GOTTA go somewhere babe... And unfortunately, where we're having our gathering of beer guzzlers, doesn't have a bathroom... so... rude as it sounds, the floor's gonna get rather nasty after awhile.

So, we are actually dumping a lot of nasty waste energy right back into our polarity phase circuit.

Now, would it make sense to put all that nice, expensive and sensitive gear that's DESIGNED to amplify noise signals on the SAME circuit where it's going to be creating it's energy as a pee trough?

Uhhh... not if I can help it, no.

"But what about ground?!? Won't it pick up the noise and carry it away?"

BWAHAHAHAHAAA!!!

no

Ground is the origin path for voltage and current.. or if you prefer... The final destinnation for voltage and the origin path for current. (The former is correct when discussing vaccum tubes, sorry)

If there is noise in a circuit, it does not exist on ground. It exists because of ground. (I hope you're still with me on this.)

Electricity coming in on that transformer would still power all the stuff in your home if it only had two wires... the hot and the neutral (center tap that is tied to ground). The ground is there as a current path... actually, a safety path. The neutral is the real reference side of that phase. It just happens to be at ground potential.

So, neutral is the same as ground in that it does not carry noise... it is what noise (and usuable signal) is referenced to. Noise is only apparent on the +VAC side, in reference to noise as we're discussing it on the primary/input side of powered electronics gear.

If you look at a transformer secondary that is a center tap secondary, you can generate a modest amount of signal/noise on one leg and it will not show up on the other leg. This is due to the phenomenon of hysteresis in inductors and due to the typical ferrite cores and interleaving techniques when transformers are wound. Lesser designs are where this becomes an issue... and all the more reason to keep like items together to minimize dirt and noise from being on the same "leg" as sensitive electronic devices.

I would go on through balanced line and unbalanced line circuits, but we're not really discussing that type of power conversion or amplifier circuits... so...

Why do we reccommend putting all your gear on one "leg", and not put anything else on that leg???

Cause it's smart to. It keeps all the dirty items together and all the clean items together.

See??? Simple, common sense approach... but not without it's moments of having to deal with realiy silly physics.

Excellent Max.

Noise is the issue and it is the residual noises born of different types of demands that create havoc amongst sensitive amplification equipment. Motors create a certain type of field and they can be found in many appliance types of usage. Heaters and other sorts of radiant types of circuits do something else to electricity.

So, in your installation of a sub-panel fed from your house panel, even though the length of the feeder will act as a sort of resistor and therefore buffer the input to the secondary panel, if you load your sensitive equipment on the same phase as the one in the main panel that feeds the furnace blower motor, the exhaust fan in any bathroom, the exhaust fan in the kitchen the television and other related devices upstream from this sub-panel, you are going to be encountering some noise on the line.

But you might argue that its only a single 240V breaker feeding out of the main panel.....Yes, and it sits on both sides of the bus in that panel and all applications relative to what is operating on that particular phase in the main panel will simply transfer to the new install....although, as I said, at some reduction due to the length of wire feeding it.

The most efficient way to to remove possible line noise from a shared service is to install a transformer at the new panel. In doing so you also create a new point of reference to ground through the new windings. There are lots of relatively inexpensive transformers available. A simple buck/boost 240v/240v @8 or 10 KVA's will get you 30 amps of clean and green power for anything you might want to plug in. Most will mount on the wall and arent very large. You could get crazy and buy something very technical like a shielded tranny but why? Home studios even small commercial installations simply dont need anything more than a second set of windings to protect from stray noise. If you are in an industrial park with a couple of manufacturers and big machine shops then the answer is a different one as is the budget.

Does that answer your questions or clarify the situation?

One other comment......on 'balancing the loads'.....Yes, this is a good practice. Because most household loads are not 'continuous' in their nature, getting a handle on a balance of these loads which come and go fairly often is a crap shoot. The main load in a house is always going to be water heating and if you have natural gas then its a moot point. I say this as main load simply because it is the load that can be counted on to be doing something most parts of a day in comparison to most of the others. Heating and cooling can be considered there also though depending on you climate in your area it may not be continuous.However if you have long cold winters and an electric furnace, this is going to spin the meter a lot more than the water heater at times of demand. Same with cooling in a warm climate. BUT...I reiterate, the water heater is always doing something and most of them are dual element and can draw 5000 watts. Rarely are both elements going at the same time unless you have a large number of showers per day.

Aint electricity fun?? I've had fun with it for almost 40 years now.

There's other reasons for balancing the load. For instance, as in many cases, folks start to have ground loop issues even when they are plugging into different outlets, within the same room. The quick and dirty way to fix most of these problems from ground loop, is by sticking on those 3 into 2 AC outlet plug adapters. And this usually corrects for ground loop hum. Especially since most folks use patch cords where the sleeve or, pin one, are grounded at both ends. While this may correct for the ground loop hum, it also presents a serious shock hazard. And while it may not be 240 V, it can definitely be a killer amount of 120 V. And plenty a rock 'n roller has been killed over the years because of that. As soon as their lips touch the metal ball of a microphone while they are holding their guitar, they instantly become deadheads of the truest kind. In fact it only takes one amp, at virtually any voltage, to kill a human being almost instantly. So whether it's 12 V from your car battery or from a 120 V ground loop, you're going to wake up dead. And then your ghost will wonder why ya can't pick up that Fender guitar anymore? And that will make your music production really frustrating. I mean you want pass-through monitoring just not a pass-through guitar. LOL. And nobody will like your ghostly singing in deep reverb, in the middle of the night.

I'm in a different and unique situation as a Remote Truck owner. The technique I utilized in my electrical wiring within the truck, all passes through a 100 pound, electrical isolation, step up/step down, electrical isolation transformer. I can pull 104/120/208/240 V, Single or three phase, without a ground and without a neutral. Then, the secondary of my transformer has a center tap, which then becomes my neutral also tied to the ground connection but not actually to any ground at all. And there is no risk from shock as there is no ground potential. But I also must balance the load on the secondary output side of that transformer. So my equipment is not being powered from just one side of that transformer output. And my multiple electrical outlets are all same length cabling to the breaker box within the truck. Which also lowers the potential of any ground loop activity. The transformer also has a limited frequency response which helps to filter out other electrical interference and RFI. The transformer only needs to pass 50 or 60 Hz and nothing beyond that. Many control rooms at other studios also rely upon a separate power isolation transformer, for each control room, in a multi-room facility so as to also help prevent any electrical interaction between different control rooms. Some Transformers also help to regulate voltage such as ferrou-resonant transformers and you'll find a lot of those at other studios. So it's really not just about balancing the power. It's really more about clean power. And a balancing act so as to not cause any stray differential voltages between pieces of equipment. And no electrician has ever been able to actually figure out my wiring scheme and how it works LOL. Go figure? There are other types of regulated and balanced power distribution devices that also help to lower noise. While my distributed power within my control room is not what we would call balanced i.e. 60 V on each Edison lug, with a reference to the ground pin. But because of the isolation transformer and my wiring scheme, it's balanced power within the transformer being distributed in an unbalanced way, which still took my noise floor down quite remarkably. However the electrical isolation transformer I have, in and by itself, draws more than 800 WATT's of power, with no equipment plugged in, at all. So one must figure in that additional load as well. And then there is the HVAC, which requires 208/240 V. I can take that on the raw incoming side, that has to include a ground or, I can take it from the secondary side of the transformer, which requires the 700 kVA capabilities of a 100 pound electrical transformer. I almost went with the 1000 kVA transformer, which now in hindsight, would have been a better decision when we outfit a video control room in the truck. And where the power supply connection lugs on the transformer, started to melt. In fact I had to repair that transformer about 10 years in, because of that.

Back in early 1973, when I went to work for Flight Three Recordings Inc., the largest multi-room recording facility, south of NYC, bigger than anybody in Philadelphia at the time, had a pair of Scully's, in the control room I was working in. Wired by somebody who really didn't know what they were doing. So one day, I had one machine in high-speed shuttle mode. Rocking the buttons between fast-forward and rewind as my other hand went to the other Scully. Soon as my finger hit the ground, on the Scully right next to the one I was using, I got a good shock, a hell of a shock. Only to find that Craig had removed the ground pin from the electrical plugs on both Scully's, because he was feeding a console with unbalanced line inputs, the stupid ****! And both electrical outlets on the wall, were right next to each other and likely with the same distance of cabling. Which really makes for the argument to stick everything on one side of the electrical feed. Of course this industrial building was 208 V, three phase but doesn't really make for any difference in a single phase house power scheme. And that's why God created AC voltmeters, so we don't kill our clients.

I 'bout laughed myself to death over this one. Ouch! It hurts when I laugh.
Mx. Remy Ann David

MadMax & Davedog,

Got it! I can't thank you guys enough for your detailed explanations. I understand everything you've said and can see my path forward from this point, sort of.

Davedog, I realized the relationship of the sub-panel to the main. In fact, that was my next question. Thanks for answering it in advance. A few more questions, if either of you wouldn't mind. This is great!

I'm installing isolated ground receptacles (all the studio receptacles going to the sub-panel will be IG; the lights are on the main panel). I'm guessing, from what you guys have said, that this should solve any ground loop problems, but not necessarily the interleg interference issue. I'd appreciate your clarifying thoughts on this point.

I like the idea of installing a transformer to isolate the sub-panel. The main panel breakers feeding the sub-panel are 60A. The feed comes around the house underground to a J-box, where it is split onto two pairs of breakers. A pair of 40A GFCI's on the feed for a future hot tub in the back yard, and two 30A breakers on the feed coming back inside to the sub-panel for the studio. Unfortunately, the hot tub motors will inject noise at a closer point to the studio feed than I would like. All the more reason for installing a transformer.

The buck/boost 240V/240V @ 8 or 10 KVA's allowing 30A seems perfect for my application. I'm not familiar with the term "buck/boost". After looking it up, would this term still apply to a 1:1 isolating transformer? None of those I could find online had 1:1 ratios.

Also, how do I hook it up? I'm guessing there's a center tap on each winding, so I just connect the hot wires from the feed to the ends of the primary and the neutral to the center, same for the sub-panel on the secondary, presumably with the polarity the same on both sides, and the ground connected to the transformer chassis on both sides. Correct, or no?

In any event a thorough analysis of the loads on the main panel is in order. We just moved here a little over a year ago, so I've recently done a circuit analysis. A few circuits I've not been able to identify, but I'll have to do the best I can. I just need to have a look at how the loads are distributed.

RemyRad,

Thanks for filling in some of the more subtle details. I've read a few of your posts. Always knowledgeable and very helpful.

If installing a transformer on the sub-panel also helps filter out RFI, that would be great. Most of my equipment is connected using balanced audio lines. The few pieces of gear I have that are unbalanced are connected using audio grade isolation transformers. Apart from being dangerous, I find lifting the ground on the power cord often doesn't stop the hum anyway. We all know how frustrating it is when you plug in a piece of new or rented gear, and suddenly get a background chorus you hadn't planned on. I'm hoping the IG receptacles will solve any ground loop problems.

I completely get the grounding issue:

Many years ago, I was playing in a band at the Canadian Pavilion at Osaka '70 (the World's Fair) in Japan. In the center of the pavilion was a 2500 seat arena, with a stage that floated on a large pond, replete with lily pads. Rising up from the center of the pond, supposedly protecting the stage from the weather were three giant mirrored columns with a huge vinyl umbrella atop each one. We were there partly during Japan's Spring rainy season. It rained every day for a month. At times, the rain was quite heavy. Much of the time it was just a mist that hung in the air, making it difficult to see and breathe.

One Thursday afternoon, we were in the middle of our set, when the light mist turned to rain. The stands were about two-thirds full, a sea of umbrellas. The Japanese had come prepared. We were just ending our second tune, when a flash of sheet lightning bounced off the pond and everything around it. The four members of the band, including me, could feel the current go from the mics through our bodies and out our guitars. We looked wide-eyed at each other, politely said "domo arigato", and shut down immediately.

The Japanese tech crew were excellent, so I doubt if that was the issue. In fact, maybe the system was well grounded and that's what saved us. I once experienced a direct lightning strike on a taxi I was driving. A ball of fire literally rolled around the hood opening, came inside and lit the dash up like a Christmas tree. I lifted my hands and feet in the air and held my breath until it dissipated, then shut the engine off. Electrical current is nothing to fool around with.

And yes, I will be installing lightning arrestors on the main panel.

Looking forward to hearing your responses.

Thanks again guys,

-Wayne

Hey Wayne.....In response...Glad you are seeing the wisdom of these posts. It will serve you for a long time.......probably longer than any software you might be using....I'm really pissed at Waves right now so forgive me..........The only thing I will install is a UPS. I only need something for three hours for a shut-down so its not a big deal. I very rarely lose power here. Its great to live in a grid that has a number of options for the utility.........

ISO grounded receptacles are fine....a little overkill if you were to ask me in person...I've wired studios that had hospital grade devices everywhere....Fine if you have the budget......Once you have a transformer in place theres no need to go above commercial grade devices....Your isolation in this case begins at the new tranny.....Anytime theres another set of windings that makes a neutral you are isolated from any feeder noise....maybe not as effectively as an isolated tranformer might be but enough for most applications and "home studio" is one of them.....

YES..1 to1 windings. Plenty of them to choose from..........search function..."isolation transformers" buck/boost transformer.....etc....You do NOT need some high=tech transformer for this. As I have said, windings create another service which has no aspects of its feeder......A isolation transformer will only have a solid reference to ground as a difference from any basic transformer used in this scenario and would be redundant. If you are powering 29 outboard Manley preamps and you live close to a power station then lets get an Isolation tranny in place.

Otherwise save your money for sound control.

I purchased my electrical isolation step up/step down transformer from the Signal Transformer Corporation, here in the US. This transformer has multiple primary taps and multiple secondary taps. Allowing one to match the incoming voltage and allowing one to tap, for proper output feed voltages. Both with split primary and split secondary windings, provides for your center tap.

When I was planning the design for my Crowmobile.com truck, I contacted John Ariosa at Sheffield Recordings Ltd. whom I had known for 17 years. He has one of the best remote trucks in the country in a huge semi trailer that was all custom-built. He told me I needed to have a Liebert Computer Power system which he had installed on his truck. Well that was more than $4000! So I contacted K00STER McAlester, from Record Plant Remote who told me he was using a Signal transformer and that was all I needed. And he was right. The Liebert obviously offers a level of protection and regulation you won't find from a single transformer. But that transformer along with something like a Furman, regulated distribution power device, will certainly be much more affordable and just as effective. And of course perhaps some UPS devices. The Liebert has all of those elements built into it. So I just did it the à la carte way of system integration.

We should connect sometime? Like into the electrical service LOL. I think my minor electrocution episodes coincided with my love of ZAP COMIX? (Circa 1970) I'm not only a pale white Caucasian, I'm crispy brown around the edges MMM MMM yeah. Turn me over. I'm done.

My mixes are electrifying!
Mx. Remy Ann David

Hey Dave (if I may),

Sorry to take a few days to respond. I've been researching transformers and talking to my electrician. What he came up with is an isolation transformer: 240V/240V @ 10kVA, 12" x 12" x 12" in size and costing $700. I don't think this is what you had in mind when you said not very expensive and not too large. Can you give me some approximate idea of how big the transformer should be and how much it should cost. Just a rough idea, so I know what ball park I'm in.

I think my electrician is struggling with the terminology, as I am. It seems we don't use the term "buck/boost" in Canada. We call it "step-up/step-down", so as soon as we start looking at a 1:1 transformer the guy with the book automatically goes for an isolation transformer, which if I understand what you're telling me, is a specialty transformer that has a whole lot of features that I don't need. You said there were lots to choose from, which is great. Problem is, neither I or my electrician knows quite where to look. Any further direction you can provide is much appreciated. A link to an example would be great, if you don't mind taking the time.

I'm planning on mounting the transformer outside the house, where the feeder comes in, after the split-off to the hot tub. This will keep the noise outside, but require a weatherproof enclosure, vented to allow the heat to escape. How loud are these things?

And of course, the whole thing has to meet code.

And RemyRAD,

I'll check out Signal Transformers to see if I can learn more about what's needed in my situation. Thanks for the suggestion.

I enjoy your sense of humor. Like the anteater in Animal Crackers said when the ants dropped a huge rock on his tongue, "bery punny".

I remember ZAP Comix. One of my best friends was from the U.S. and managed a record store/head shop in Montreal, ca. early '70's, which is how I managed to see the occasional issue.

Kind regards,

-Wayne

These transformers don't need to be placed outside. They really don't make any noise of their own, anything more than any other power supply you have running. Sometimes a simple soundproofed box around it, sitting in the bottom of the rack with all of your other gear, would work out just fine. Really though, I wouldn't want to be setting it next to or near any microphone preamps/instrument preamps. And that's why you stick it back in the corner on the floor. I mean you're not going to be running any heavy industrial mechanized equipment that presents a greater back EMF are ya?

Buck strap is a valid electrical term the definition of which seems to escape me, on a Saturday night, staring at mindless television.

This power transformer is just, well, a transformer. It's got two inputs with multiple selectable impedance taps. And the same on the output side. It's just a big fat 60 Hz audio transformer capable of delivering 7000-10,000 W of sound pressure level, into the power supplies of our computers and other equipment gobbledygook. And it won't hum much because it already knows the words. And of course you certainly wouldn't want this thing under the desk of your console and preamps.

Here's another reason why I don't think you should mount that transformer outside in its own enclosure. Sure it gives off a fair amount of heat when you are running a full load upon it. But I thought you Canadian folks were a little more in step with the green conservation movement?? I grew up in Detroit. And I happen to know, the winters are brutal. So to keep it in a non-technical corner of the room, it makes a great space heater in the cold and winter time. Reducing your heating costs which exceed air conditioning costs.

But it's all fun.
Mx. Remy Ann David

Hey RemyRad,

Just to reiterate. The earlier suggestion was to put a transformer between my main panel and the new sub-panel. The idea being that all of the receptacles in the studio would be isolated from noise.

In my situation, that would mean the transformer would have to go outside the studio. The sub-panel is in an adjoining closet, which will be sound isolated, though not quite as well as the studio itself (of course, I'll need to install a fairly hefty door).

The transformer I spoke of above puts out about 45dB, hence the need to either place it outside or in the furnace room next to the closet (although there's a lot of heat in that room already).

I really would like to find a smaller, quieter, less expensive solution. I don't really know enough about the subject to understand whether the transformer you're suggesting could be wired between the main and sub panels. And if it were, would it pass code?

I can't see putting it inside the studio, then running the cabling back through the closet wall to the sub-panel. However, if it can be used in the way I've described, maybe I can build a box for it in the closet wall, beside the sub-panel. Again though, maybe that wouldn't meet code (my understanding is that there needs to be 6" clearance on all sides).

Can you point me to a link showing the transformer you're suggesting, so I can look at all the specs, and find out more about it? Please and thanks.

Is this an audio power transformer, of the type used in the power stage of an amplifier? I feel I'm misconstruing some aspects of your suggestion.

I understand the way you're using this type of transformer in your remote setup, as you described earlier. I just don't see how it would work in a home studio. Maybe I'm wrong, but aren't there things electrical you can do in a truck that won't pass muster in a residence?

Still, I can't pretend to know much about it, so I'm certainly prepared to listen and learn. And thank you for taking the time and energy to help me solve this issue. I really do appreciate it.

Davedog,

I'd still like to hear some further details from you on the specific transformer you had in mind. A link would be great, if you know of a specific product, for comparison to what is available here in Canada. Also, your comments on the size and cost, of the one I've sourced would be helpful. If you would be so kind, sir.

-Wayne

Wayne,

There's a couple of different routes to look at... Now, these are real 10KVA isolation transformers... and 10KVA is indeed some serious power.

[[url=http://[/URL]="http://www.temcoind…"]Federal Pacific SE2N10F FT2065 - Isolation Transformer 240 x 480 Primary 120/240V Secondary - 10 kVA 60Hz 1 Phase NEMA 3R Copper[/]="http://www.temcoind…"]Federal Pacific SE2N10F FT2065 - Isolation Transformer 240 x 480 Primary 120/240V Secondary - 10 kVA 60Hz 1 Phase NEMA 3R Copper[/]

APC WW 10KVA Isolation Transformer

When you get much above 5kva, I've found that mechanical hum is a real issue. So, getting it outside of your enclosure is a good thing.

Another good thing is that isolation transformers are pretty simple devices, and unless they're physically destroyed, you're pretty safe to buy them used at significant savings.

I was looking at a 15kva costing upwards of $3000 and found one on fleabay for a coupla' hundred and then another hundred-ish to ship it from California to NC.

I put my transformer outside on the same pad as my HVAC units. We fed the transformer from the main panel, and then brought the clean power back into a sub-panel.

To keep things as "clean" as practical, I put all of the converters, mic pre's and outboard gear on the same leg, putting all the other "amps/misc" on the other leg... e.g. the control room on one leg, with the rest of the tracking rooms on the other leg.

Then too, call me Capt Overkill if you want, but I seriously believe in doing what it takes to get you into solid margins of safety and minimal noise. So, while 15kva was expensive, it's giving me a power margin of about 300% for an ~1600 sq ft studio... giving me PLENTY of "head room" to grow in the future.

If you're only looking at providing clean power for the control room and no real plans to expand your gear too much, I would honestly suspect that 5kva should be plenty of power... at a significant cost savings compared to 10kva.

Just some food for thought.

Hi MadMax,

Thank you very much for providing the details I asked for. You've pretty well nailed it for me.

The Federal Pacific SE2N10F FT2065 is very similar to the unit I had specified locally. At $522. it's slightly lower in cost than the one I can get here, but with the shipping from the U.S. could end up costing the same, or a little more.

I called APC about the WW 10KVA. It's larger, heavier and costs $1450 USD. Not really an option for me.

It would be fairly easy to put the transformer outside. The weatherproof enclosure would add size and cost, but it would definitely simplify the hum issue. The sub-panel is running off 30A breakers, which would need about 7.5kVA. My electrician tells me I have to allow for 25% over capacity, which boosts required capacity to 10kVA. The smaller unit would be lighter, generate less noise, and cost less, so I'll check the requirement with my local inspector.

I could put the transformer in the adjacent furnace room, but I already have the furnace, air handler, water heater and a whole-house dehumidifier in that room. The dehumidifier is quite noisy (45dB). It's currently hanging from the joists on cables, which will receive four spring-type isolation mounts, which I've bought but not had installed yet. I can't do that on my own!

Point is, in total that's a lot of equipment in the small, 6' x 9' furnace room. So outside would probably be best.

I'll check around to see if I can find a used transformer. I certainly have no problem buying used gear, if it's been well looked after. That's an excellent idea?

Thanks again, for closing the loop on this for me. I have all the information I need now to go ahead with it.

I can't express my appreciation enough, guys. :cool:

I'll post again when I've sorted it all out, to let any interested parties know what I've done and how it's working.

Cheers,

-Wayne

Sorry I didnt get back....I'm tracking and mixing a record....Max has you going ....good deal. Let us all know how it turns out. BTW...most transformers rated for wet and damp locations dont have really elaborate cases....usually just a drip barrier or a rail.......If you're going outside its best to build a nice little doghouse instead of paying a premium for 'weatherproof'. That way you can look at Nema 1 rated trannys rather than Nema 3.

Davedog, post: 397467 wrote: Sorry I didnt get back....I'm tracking and mixing a record....Max has you going ....good deal. Let us all know how it turns out. BTW...most transformers rated for wet and damp locations dont have really elaborate cases....usually just a drip barrier or a rail.......If you're going outside its best to build a nice little doghouse instead of paying a premium for 'weatherproof'. That way you can look at Nema 1 rated trannys rather than Nema 3.

Ooops... yeah... forgot to mention that!

We had a "hood" made from sheet metal that acts as the weatherproofing enclosure.