@jwolchak- I'm not sure that's true. For a residential application the iso transformer would have to be tied back to the main electrical system ground. (You cannot float the ground on the secondary, as I understand it, or ground to a different grounding point without violating Code, at least in the States).
It will nonetheless isolate from certain things, but not everything. I'm currently using a large 10kVa isolation transformer from Controlled Power with a high K rating between the panel and subpanel for my system and it's great; the unit, which is large at 400+pounds, is installed in a weatherproof cabinet outside.
This is a more standard EI type, not a toroid. I'm a pretty big fan of iso transformers.
I've encountered different meanings for 'fully or completely isolated' in this context- some see a completely separate ground as essential but I don't think it is possible to do for a residence and stay within Code. (I'm not a Code expert or electrician, just used these things and dealt with their installation). Others here with a working knowledge of Code could amplify or correct any misstatement on my part.
Welcome to the 'Gon.
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Dedicated line is great. You could isolate the dedicated line completely by having your electrician install a isolation transformer. Square D makes them as well as many other manufacturers. You could even go so far as to place the transformer between your panel and subpanel (if you went wild and installed that too).
But a #12awg (2) wire plus ground, metal clad cable, or EMT raceway with wire to feed a high quality plug will work wonders for the sound quality. I think isolation transformers are the best if you live in a building with many other residents feeding off the same main service you are. |
Sometimes, it's just a matter of luck. Our house was built in 1952, the original wiring was two-wire, w/o ground. The boxes are all metal, and are (from all I've seen) grounded separately from the circuits. It's dead quiet, zero hum. In the twenty years we've been here, we've replaced the fuse boxes with a modern breaker panel, replaced the original meter with a 400A meter socket, re-did the service drop, replaced much of the old two-wire with modern Romex w/ground, as I've been able during remodels, etc. It was a fairly basic arrangement, done well (for the time), and wasn't ever botched up.My only caution to anyone would be to have the work professionally done, if you aren't certain what you're doing. Goes double, if you're in a multi-family dwelling.
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Lots of good posts already so I won't add any redundancy, just will comment that I ran a dedicated (also called a "home run") line to my dedicated listening room. The results were entirely satisfactory. Worth the $, IMO. YMMV
Tom |
@french_fries ,
You could do what I did and add a subpanel for your audio lines. The electrician tied into my house service panel and installed two dedicated 20A breakers, Romex, and 2 Hubbell duplexes which are grounded to the subpanel (not self-grounded).
Dedicated lines are not completely isolated, but in my case, the noise floor was lowered and a buzzing sound from an old circuit was eliminated.
And @jea48 helped advise me along the way.
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I had a great electrical contractor in Brooklyn when I lived there- sadly, he is in prison for life. When I saw the NY Post article about it (I had moved up to the Lower Hudson Valley by that point), I told my wife, "I’m tempted to go to court as a character witness. And say, ’Look judge, I know the guy was convicted or plead out to some really bad stuff, murder, embezzlement, money laundering, kickbacks, obstruction, etc. but you gotta realize, this guy was an unbelievably good contractor. You know how hard those are to find?"
You’ll be in good hands with @jea48 and some of the others here who really know their stuff.
A dedicated line will not isolate you from electrical gremlins within a system that shares ground with other stuff, even within a private house. It is still a good idea, if only to get a new fresh run, unencumbered by other appliances or connections. That does sound cheap, even by the standards of the guys with, ahem, you know, good connections? :)
good luck,
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I want a newer circuit breaker box but I wonder if I'm just spinning my wheels. It's not the money, and the box is ancient, but OTOH before I call the electrician is this really worthwhile? I already have a dedicated line to the stereo...and the hospital outlets, and a bunch of cumbersome wire, also. Oh, and Also the power company wants to install a surge protection device to fit under my meter outside. The air-conditioner company says this is a good thing to protect my investment. Which is pretty substantial. |
Georgehifi, ground clamps on water pipes are frowned upon in the NEC
We use both, earth spikes and the water pipe, if you have good salinated ground earth spikes work a treat, but if it's not, then the backup water-pipe is great to have also. Cheers George |
dumbeat OP
71 posts11-27-2018 3:11pm
Im in Brookly NY. Should have mentioned. Just a guess, the electrician will not pull an electrical permit? $300 for each dedicated circuit would cover the material. His labor must be free. Though the NEC is the electrical code book, States, counties, and cities, use across the US they do not have to fully adopt it in its’ present form. They can amend it as they see fit. NY is no exception. Your electrician will know what is required for your city. Electrical code as a rule is bare minimum. Nothing prevents you from exceeding bare minimum standards. I would assume the new circuit/s will have to be installed in a metallic raceway. No Romex.... More than likely because it’s an old building surface mounted raceway and boxes. Just a guess the electrician will recommend Wiremold raceway and boxes.Example of: https://www.platt.com/CutSheets/Wiremold/500%20and%20700.pdfAs a rule for audio applications: No multiwire branch circuits. There in, no shared neutrals. Do not share a common raceway with other branch circuits. Each dedicated circuit should have it’s own raceway. To prevent the chance of ground loop hum the hot and neutral conductors should be slightly twisted together and the safety equipment ground wire pulled in along side the twisted pair. (Size raceway accordingly) Read pages 30 through 36. https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdfAll dedicated circuits that will feed audio equipment that are connected together by wire interconnects should be fed from the same Line, Leg, from the electrical panel. Line 1 or Line 2. Not from both. 20 amp circuit/s only. Why waste your money on a 15 amp circuit/s to save a few bucks. Also..... Most after market audio grade duplex receptacles come in 20 amp only. Per NEC and AHJ (Authority Having Jurisdiction) a 20 amp duplex receptacle cannot be installed on a 15 amp branch circuit. On the other hand 2 ore more 15 amp receptacles can be installed on a 20 amp branch circuit. A duplex is two. Jim |
I think one member is jea48, and it looks like builder3 may be, not sure about that. |
The NEC is the National Electrical Code in the U.S. Covers every state. Personally, I’d run 12 wire for 20amps, rather than 14, there’s virtually no difference in the price of the material, compared to the job as a whole. Beyond that, I’ve no idea about audiophile grade connections, etc. Do your research ahead of time, or let the electrician know your plans/wishes before he’s on site, not after.This all presumes that it’s even possible to install a dedicated circuit in an old building like you describe. You may be downstream of other sub-panels, and the like. Georgehifi, ground clamps on water pipes are frowned upon in the NEC, have been for years, even though thousands still exist. Anything new almost always gets modern 10’ ground rods driven into the earth, and in pairs. Too much old iron plumbing has been replaced in pieces with plastic, disconnecting the electrical grounds. You may already know this, of course. Also, at least in the part of the U.S. that I'm familiar with, electricians don't work on any part of the service upstream of the meter, such as the "drops". Those are done by the local utility district. And as a disclaimer, I’m not an electrician. Good luck.
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This is a commercial HUGE building in Brooklyn. Aside form street power there is a lot going on in the building itself... It is my thinking that a dedicated line with proper ground would still be beneficial. He is charging me $300 per line... Not sure i have anything to lose...
Just want to get as many tips. Well your at the mercy of the buildings wiring. Yes do what you are going to do. For all your line level equipment, I suggest to use a 110v to 110v isolation transformer. Something like this. And if you use them, plug your mains filter distribution board into the isolation transformer, and your line level gear into the board. http://www.bkprecision.com/products/power-supplies/1604A-single-output-isolation-transformer.htmlFor your power amp/s, plug direct into the new dedicated heavy duty wall outlet. (NO power conditioners, they sap the dynamics.) Cheers George |
This might take some time but there are a few members here who are steeped in this, with one or two in the extreme and they may not see this as I haven't seen them post in awhile.
Having said that, do a search on "dedicated lines" and you'll see lots of discussion on it. It will take time but the few I mentioned will pop up repeatedly and you can zero in on their thoughts and maybe PM them with your particulars.
I can't, for the life of me, remember their names.
All the best,
Nonoise |
Here is a tip: plant corn early. |
This is a commercial HUGE building in Brooklyn. Aside form street power there is a lot going on in the building itself... It is my thinking that a dedicated line with proper ground would still be beneficial. He is charging me $300 per line... Not sure i have anything to lose...
Just want to get as many tips. |
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The electrician hopefully is a fairly smart guy or gal so I would begin by showing them what you want to connect to the receptacles they should be able to tell you what you need. Most likely a 15 amp circuit will be enough but if you want a 20amp ask for the price difference. The next thing I would ask for hosptial grade receptacles as they will grip a lot better than residential grade. They might be restricted by code and panel box manufacturer as to the type of breaker but get the best available. |
Im in Brookly NY. Should have mentioned. |
A 15 amp circuit is 1800 watts and a 20 amp circuit is 2400 watts. A 15 amp circuit is sufficient! |
Here in US, each state may have a slightly different code requirements for the electrical work and a certified electrician will and should not deviate from the code, no matter what you ask him to do, of course aside from tightening obvious loose connections. In my state, the only options I had were the choice of the 15 or 20 amp - I picked 20, and the gauge of the (Romex) wire; 10 or 12, and I picked the thicker gauge even though the electrician was adamant that it will make no difference in the sound quality. I also suggest buying some good quality outlets with good tight connections for the power cord.
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In Australia I would ask for quality 20A cable to be used, also get him to use high quality ac power points, and use dedicated very good HQ circuit breakers in the service box.
Also if he's licensed for it, get him to tighten all connections (neutral active and earths) check the earth on the water pipe,
add an earth spike if he can also
, all connections in the service box on both sides of the of the metering unit, also outside on the barge board of the house, and if he's able, on the street power pole that brings in to the house barge board.
Cheers George |
