Dedicated lines for power

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I assume the transformer that feeds your residential housing units, single family dwelling unit, is an isolation type transformer. There in the primary and secondary windings are not electrically connected together. That means to create an AC grounded system one leg of the 240V secondary winding is intentionally connected to earth as well as bonded, connected, to the service equipment metal enclosure. The intentionally grounded leg becomes the neutral, The Grounded Conductor.

As for the primary voltage that feeds the primary winding of the utility transformer found in residential neighborhoods in the US it can vary. In my neck of the woods the voltage is 7200Vac nominal.
the 7200V is one hot leg to neutral of a 13200/7200V 3 phase 4 wire WYE AC grounded power system.

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It's all about electrical safety.
You would not believe the electrical safety that is required for new residential dwelling units built in the US.
Our NEC Code is revised every three years. In 2005 big electrical changes were started. Even more in 2008, 2011, and the current 2014.
IF the AHJ, (Authority Having Jurisdiction), adopted all of the 2014 NEC Brian Gupton's electrician would not be able to wire the audio grade Oyaide R-1 duplex receptacles to his new dedicated branch circuits.
http://www.vhaudio.com/oyaide-r1.html
That is unless the duplex receptacles are Listed Tamper Resistant and have the child safety shutters that cover the hot and neutral contact slotted holes on the front of the receptacles. And of course the receptacles have to be safety Listed by a recognized testing laboratory. Example, http://www.leviton.com/OA_HTML/SectionDisplay.jsp?section=42525

The breakers in the electrical panel that will be used to feed the dedicated branch circuits would need to be AFCI. Example, http://www.schneider-electric.us/en...o-combination-arc-fault-circuit-interrupters/

 

Yes, a wye configuration. The star point of the transformer is used to connect earth and neutral directly to the system ground at the substation. Each house is connected to a single phase. The earthing configuration dictates how earth and neutral are distributed to the house: (i) Terra-Terra were the house is supplied with phase and neutral conductors, but no earth conductor, and an earth rod uses Earth as the return path back to the system ground at the distribution transformer; (ii) Terra-Neutral-Separate provides the house with phase, neutral, and protective earth conductors; and (iii) Terra-Neutral-Combined-Separated were the house receives a phase conductor and a combined protective earth/neutral conductor.

It was the TN-C-S system I was trying to describe in a previous post, but had no idea what it was called. I thought I best at least make a reasonable effort to find out what I was talking about, and also came across the other two systems, which I never knew existed. TN-C-S is apparently our most modern and commonly used earthing system.

I highlighted and right-clicked on your "3 phase 4 wire WYE AC grounded power system" to access a search, and headed off on what turned out to be a bit of a marathon of research. It was good fun. I enjoyed it and learned a lot. I would like to thank you for taking the time to post a reply which was both informative and stimulating enough to encourage further investigation.

Well there's a good thing... Just kidding. I know what you're saying.

Yes, we've had child-proof sockets over here for a while now. That'll be EU interference probably. They're always up to something.

Sometimes I think the world's gone mad, but most of the time I know it has!
Thanks for your input. Household power supplies have now clicked into place.
Best regards,
John.

 

The whole child proof receptacle this is one of the biggest PITA codes. It's not unusual for an electrician to install them and then swap them out after his final. Shhhhh I didn't say that!

 

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Not all receptacles are created equal. There is more to a receptacle than just its' ability to grip the plug blades and equipment ground pin tightly.

An orange color receptacle, there in an IG, isolated grounding type receptacle.
An IG receptacle can also have a face color of other than orange with an orange color triangle found on the face of the receptacle. Not all IG receptacles are hospital grade type receptacles.

What is an IG receptacle?
An IG receptacle has the equipment grounding contact, the U shaped hole in the face of the receptacle isolated, insulated, not electrically connected, to the metal back supporting strap of the receptacle. NCR, National Cash Register, used to and maybe still does, spec an IG receptacle for their equipment. The theory is objectionable AC noise travels on the metallic conduit systems in buildings. Lots of metallic things within a building for the AC noise to travel on and through. Electrical conduits, metal HVAC ductwork, metallic plumbing pipes, drop ceiling grid, metal decking of the building, steel beams, the list goes on and on. Again, theory that an IG receptacle can help prevent unwanted AC noise from entering sensitive electronic equipment through the safety equipment ground……

How does NEC Code treat the IG receptacle?
First an IG receptacle serves no purpose when used on a branch circuit that is not contained within a metallic raceway or conduit. In fact, if an IG receptacle is installed on a branch circuit like NM-B cable, (Romex is a Trade Name of ), and a plastic box is used a conductive metal cover face plate should not be used. The metal plate could become electrically charged and be dangerous. The cover plate 6/32 mounting screw hub of the IG receptacle is secured by the back supporting strap and is not connected to the equipment ground contact of the IG receptacle.
Bottom line an IG receptacle serves no purpose when connected to a branch circuit fed with NM-B cable.

When an IG receptacle is installed in a metallic box connected to a metallic conduit system.
NEC says the IG safety equipment grounding conductor wire has to be insulated with a green color, or a green color with a yellow stripe.
The IG equipment grounding conductor has to be installed in the same raceway or conduit with the current carrying branch circuit wiring.
The IG equipment grounding conductor has to connect to the equipment ground bar in the panel the branch circuit is fed from.
[i/]Exception[/i]. NEC allows the IG equipment grounding conductor to pass through a sub panel, boxes, conduit system, unconnected along the way, to the main electrical service panel the sub panel is fed from and connect to the bus/neutral/ground bar the service neutral is connected to.

Nowhere in the NEC does it say an IG type receptacle’s IG equipment grounding conductor can be connected to an isolated earth driven ground rod.

 

I had an IG receptacle damn near kill me years ago. When I used to install security systems at the entrances of retail stores (the "tag" bad systems) we would routinely ask the owner to have their electrician install a dedicated circuit for our equipment in the ceiling. We didn't need it for any real isolation, but to make sure it was powered 24/7. The EC took that to mean an Isolated Ground and sure enough installed an orange receptacle at our location. Somehow he managed to swap the ground and hot words on the receptacle and being isolated it did not trip the breaker and sat there unused for a year before they added the security system. When I plugged out system into it, it energized the chassis of our system which when I touched it, got my attention. Add that I was standing on a ladder and was accessing through a metal hatch in the ceiling. Fortunately my elbow was resting on the metal in the ceiling so it was only my arm that got the brunt of the current and while hurting like hell I managed not to fall from the ladder. Had anything else been grounded I could have been very bad.

Suffice it to say I have absolutely no love of orange receptacles in an application that does not require them. Yes the EC made a horrible mistake in his job, but it still created a very unsafe condition unnecessarily.

Just an anecdote, but something to be aware of.

 

IF the #8awg wire connects directly to the receptacle, first off the receptacle would have to have side terminal screw and plate connections.

Simple instructions.
Strip the insulation from the #8 stranded wire slightly longer than recommended by the manufacture of the receptacle.
Split the strands evenly into two groups forming a fork looking lug.
Cut the ends of the finished product for the length of wire needed for the termination.
Insert the wire under the terminal plate of the receptacle. (The equally split strands of the #8 wire will straddle each side of the supporting terminal plate screw.) Tighten down screw onto terminal plate.

Will the electrical inspector red flag the wiring method? Depends on the inspector.

A Sta-Kon crimp fork lug would probably work better. At least for a mechanically made connection.
http://www.grainger.com/category/fork-terminals/wire-connectors/electrical/ecatalog/N-ipxZ1z0r1a2

 

LOL, sorry I can't help but laugh, LOL. I would be willing to the electrician was color blind.
I bet you used a meter to check IG receptacles after that experience.

 

Considering that I do Commercial Lighting controls these days, almost any 120 jolt kinda pales in comparison to getting tickled by 277.

 

Some random thoughts, mostly pertaining to US type AC power systems:

Receptacles:
a] Almost all quality dual 15/20A receptacles will only accept 10AWG and smaller wire. If your circuit has larger wire, use a short 10AWG pigtail to join the larger wire.
b] 15 and 20 Amp dual receptacles. The only real difference is the plastic cover plate that allows a 20A plug to be inserted. The current carrying metal parts of a 15A unit have to be rated at 20 Amps. If all your plugs are 15A plugs, you don't need 20A receptacles.
c] Hospital Grade Receptacles have:
1} A strong plug gripping design.
2} Plating to resist repeated cleaning with harsh solvents.
3} Documentation.
So you pay a lot extra for good plug gripping that is available for much less cost.
d] 20A receptacles are not permitted in 15A circuits.

Circuit wiring:
a] Oversize wire is always good.
b] Romex® is a better choice than typical metal conduit wiring. Bill Whitlock has a paper on why this is true.

The Stake in the Garden:
The ground rod is mostly for safety during thunder storms! It adds nothing from an audio power quality perspective. If the building inspector is happy, then you should be happy also.

GFCI and AFCI breakers & receptacles:
New work may require these. Both GFCI & AFCI units can be problematic with legacy or boutique equipment and power conditioners.

Cyro:
NEC rules state that all units and even the bits & pieces hardware must be used following all manufactures instructions. Way down in the fine print of the manufactures instructions is storage minimum temperature. So when you cryo a unit or a wire, you break the manufactures instructions.

 

Brian,
How'd it all go?
What did you decide on in the end?
Did you have a look at IsoTek conditioners?
John.

 

Can't say I have ever seen any reference to "storage minimum temperature" with any receptacles or plugs I have in use on any manufacturer datasheet. I'd be curious to see it. Can you post a link? Wire maybe, but I've never seen that either.

 

Here is the temp specs for a Hubbell receptacle. I would bet they are the same for the heavy duty industrial series as well.
http://www.hubbellcatalog.com/wiring/section-a-datasheet.asp?FAM=Straight_Blade&PN=HBL5362
"Operating Temperatures Maximum continuous 75°C, minimum -40°C (w/o impact)."

I wonder if anybody has ever checked with Hubbell about cyroing their receptacles?

 

Yes. I've seen that operating temperature spec before (it is on all their datasheets) but never a "storage" spec. An operating temperature spec is quite different I would say. We'd have to define "storage" I suppose if there is such a spec. LOL

Just curious. In the end it would not make much difference to me. I've been using cryogenically treated Hubbell and various other receptacles, along with plugs, connectors, interconnects, speaker cables and power cords for the better part of 13 years now with no issues. I have a couple of line conditioners that have been in continual use in that time period as well that were also treated.

Hubbell would be like most manufacturers I would expect and say that cryo is unnecessary.

 

I only have photos of the finished product. I can tell you that he swore and grunted for about an hour to finish the job. He knew that I didn't want any compromises and is a Red Seal Certified electrician, so he had the experience to finish the job off. If you are in Vancouver, you are welcome to come by and admire his handy work.

 

Don,

Just curious when you first told the electrician what you wanted, did you ask him for an up front price or did you ask what his hourly rate was and just hire/pay him by the hour plus material?

>>>>>>>>>>>>>>

Imagine this conversation between a non-audiophile electrician and an audiophile enthusiast.

Electrician: So you want 4 - 20 amp dedicated circuits. You want me to install #10 gauge Romex wire. My goodness how much power does your audio equipment draw? #12 is good for 20 amps per code. Who told you, you needed #10? So how much power does your audio equipment need?

Customer: Well, my tube CDP I think is around 50 watts. My tube preamp is around 150 watts. My tube phono preamp is around 30 watts. My Power amp is rated at 120 WPC. At full power output of 120 watts it could draw around 700 to 800 watts (800W 6.7 amps full power). My sub, I am not sure but class D draws less power than an A/B sub amp. I have a large screen plasma TV and a DVD player. I think that stuff can run off the house circuits.

Electrician: So what are you feeding all your stuff off of now?

Customer: Just the existing wall outlet.

Electrician: You know that is more than likely a 15 amp circuit, fed from a 15 amp breaker.

Customer: It's not just the amount of power the equipment uses. From what I have read on audio forums the reason for installing multiple dedicated circuits is to decouple the power supplies of audio equipment from one another. Especially digital from analog. I have also read instead of installing one using #12 wire, like for the digital equipment, and #10 for the power amp, it doesn't cost that much more to run them all using #10 wire. That way I will not be limited on which wall outlet I want to use. I won't be saying down the road later, I wished I would have......

Electrician: Well I have been an electrician for over (??) years and that's a new one on me. Like I said I will do what ever you want as long as it meets local code. I think #12 wire is plenty big though.

Customer: Are you sure?

Electrician: OH Ya, #12 is plenty big enough. By code I only need to use #12 wire for a 20 amp circuit. And you really don't have any load to speak of. I mean you are running everything plus the lights, more than likely, off of one circuit now.

Customer: Oh I forgot to mention, can you put the new circuits on the same phase in the electrical panel.

Electrician: I will have to check if you have enough empty spaces left in your electrical panel.

Customer: Somebody told me that the electrician would tell me he couldn't do that. Something about balancing the load across the two hot phases.

Electrician: Well technically that is usually the case. But in your case you don't have any load to speak of. You are feeding it all off a 15 amp breaker now. I will check your Mains and see if the hot "phases" are somewhat balanced now. The only sure way, to be honest with you, would be for me to put a recording ammeter on them for a couple of days. Loads are changing constantly, turning on and off.

Customer: Oh I almost forgot, I read it is a good idea to keep the Romex lines separated from one another by at least about 8" ....

Electrician: Why's that?
Customer: I read it helps prevent induced AC noise/voltages from being transferred from one Romex line to the other.

Electrician: Just looks at the customer not saying anything back......

Customer: So can you look over what you will need to do and give me a price?

Electrician:

 

Work is getting done tomorrow. Not doing the IsoTek for now.

 

I'd say that was pretty much exactly how my conversation went down.

 

Electrician: Well technically that is usually the case. But in your case you don't have any load to speak of. You are feeding it all off a 15 amp breaker now. I will check your Mains and see if the hot "phases" are somewhat balanced now. The only sure way, to be honest with you, would be for me to put a recording ammeter on them for a couple of days. Loads are changing constantly, turning on and off.

First almost all US homes have only single phase power! It's two legs or poles not phases.
But anyway it's highly unlikely hat you could ever balance the loads in a residence. And most of the heavy loads are 240V like heating, air conditioning, cooking & hot water.

***********************************************************
Customer: Oh I almost forgot, I read it is a good idea to keep the Romex lines separated from one another by at least about 8" ....
Electrician: Why's that?
Customer: I read it helps prevent induced AC noise/voltages from being transferred from one Romex line to the other.

Well if that other Romex® is for new lighting systems or appliances, then OK. Theater lighting system even more so.
But if all the circuits are for the audio/video system then no! Cable overheating would be the only limiting factor.
You don't even need to separate signal cables from their AC power cables by much. One wire expert, tapes his signal cables to the power cables when he does weekend semi-pro audio stuff.
But if you are doing a multi-circuit A/V room, it's best to run one heavy circuit from the main breaker box (panel board) to a central location in or near the A/V room. Then at that location, use a small breaker box, for the individual circuits.

 

Electrician: Well technically that is usually the case. But in your case you don't have any load to speak of. You are feeding it all off a 15 amp breaker now. I will check your Mains and see if the hot "phases" are somewhat balanced now. The only sure way, to be honest with you, would be for me to put a recording ammeter on them for a couple of days. Loads are changing constantly, turning on and off.
First almost all US homes have only single phase power! It's two legs or poles not phases.
>>>>>>>>>>>>>>>>>>>>>>>

I know that! The secondary winding is a single phase split phase winding. Most layman call them phases though don't they? You would be surprised how many electricians call them phases. Especially electricians that work in the commercial/industrial electrical industry. You want to guess why?
jea48
>>>>>>>>>>>>>>>>>>>>>>>>>
But anyway it's highly unlikely hat you could ever balance the loads in a residence. And most of the heavy loads are 240V like heating, air conditioning, cooking & hot water.
>>>>>>>>>>>>>>>

Speedskater,

You need stick with being an EE.
I suggest you spend a little time reading the whole thread of the OPs. At the very least have the decency to read my posts.

There are plenty of other 120V loads that should be balanced somewhat across L1 to neut and L2 to neut.

What loads would that be?

Refrigerator
Kitchen circuits above counter top/s
Dishwasher
Microwave
Freezer
Washing machine /
Gas cloths dryer (120V motor)
Gas furnace
sump pump
Lighting circuits

Speedskater you may find this hard to believe but when an electrician makes up the branch circuit wiring in an electrical panel he tries to somewhat balance out these loads.
AND NO these loads are not all running at the same time. But can you say they never do? Or that some do at the same time?
jea48
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

***********************************************************
Customer: Oh I almost forgot, I read it is a good idea to keep the Romex lines separated from one another by at least about 8" ....
Electrician: Why's that?
Customer: I read it helps prevent induced AC noise/voltages from being transferred from one Romex line to the other.
Well if that other Romex® is for new lighting systems or appliances, then OK. Theater lighting system even more so.
But if all the circuits are for the audio/video system then no! Cable overheating would be the only limiting factor.
>>>>>>>>>>>>>>>>>>

Really is that right?
So two or more 2 conductor with grd MN-B sheathed cable dedicated branch circuits that are closely run parallel next together are just fine for audio power circuits? No worry about the magnetic fields of the current carrying conductors inducing a voltage on each other? No problem with digital hash on a dedicated circuit for digital equipment loads crossing over to the analog branch circuit/s?
No problem with the magnetic fields of the current carrying conductors of the dedicated circuits inducing a voltage on the equipment grounding conductors of one MN-B cable to another?

I bet you would say it is ok to run a dedicated circuit in a conduit with other branch circuits.
jea48
>>>>>>>>>>>>>>>>>>>
You don't even need to separate signal cables from their AC power cables by much. One wire expert, tapes his signal cables to the power cables when he does weekend semi-pro audio stuff.

But if you are doing a multi-circuit A/V room, it's best to run one heavy circuit from the main breaker box (panel board) to a central location in or near the A/V room. Then at that location, use a small breaker box, for the individual circuits.
Click to expand...

It's called a feeder.... And not everybody wants or needs a sub panel.

Best regards,
Jim

 

make sure to get the carbon fiber receptacles covers. those will definitely improve resolution and tighten the bass.

 

I can say noise is a real concern in wiring. More than the "code" can discern. Just ask anyone who has dimmer noise on their audio setups (ever herd a vacuum cleaner on your stereo?) (video box noise?).

A black art at best. Proper power supply design should isolate/remove this problem but rarely does.

Probably more bout grounding issues than just a simple new wire for your audio equipment.

 

Best mod/dollar improvment?

Listen to your system late at night when the load on the power grid is much less.

You'll never get as big of an improvment in the regular hours no matter how much you spend.

Bubble burst...move on. Dream on.

 

That might have some merit if one lives in a high density area. However, a power regenerator will negate that issue.

 

I think we need a new sub-forum for Electricians. Or maybe just skilled tradesmen in general, plumbers, joiners, etc.

Gorts, could you...

 

My recommendation: I would chose Shunyata over IsoTek simply because I borrowed an IsoTek from a dealer and did a comparison with the Shunayta PS8/Defender and found it much less effective. I don't know how dependent this is on a particular system.