"Ideal" power line from Service Panel - Page 2 - diyAudio
Go Back   Home > Forums > Design & Build > Construction Tips

Construction Tips Construction techniques and tips

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 5th April 2010, 12:49 PM   #11
diyAudio Member
 
Join Date: Feb 2010
Location: Back in CT!
Quote:
Originally Posted by Zero Cool View Post
One thing i will caution is that NONE of this will pass electrical inspection if not followed to code carefully.
This is a reason I am leaning heavily toward going with rigid steel conduit with (twisted) stranded wire now. Common steel conduit is something any competent inspector will be familiar with, and anyone else working on the installation long after I am dead will understand this far better than a piece of copper pipe with wires inside! Speaking as the guy now trying to make heads or tails of the house fire waiting to happen that passes for an electrical system in my house, I can understand it from both sides of the fence. So, standard electrical service parts, used in a more careful and deliberate manner.

Quote:
Originally Posted by Zero Cool View Post
and trying to get your local inspector to understand what your doing and why is a whole other issue.
Another reason to use standard electrical stuff. He may not understand it, but at least he can recognize electrical conduit with wire inside going to a transformer and out to an outlet. Should be easier to swallow than some of the other ideas!


Quote:
Originally Posted by Zero Cool View Post
SOOOO, things like stranded wire, copper pipe etc are not going to fly past an inspector. I would suggest you speak with your local and make sure of what you are doing before you do it!
Stranded wire is used quite often (all the time in fact) in our industrial installations. Pulled through galvanized steel conduit, so I will go that route. It will be easier to work with (slightly), cheaper (a lot), and an inspector will be able to wrap his head around it. He may not understand WHY there is a dedicated line of stranded in pipe across the basement; however he only has to see that it is not a fire waiting to happen. I am not doing anything overly-exotic with the power, just trying to cross my house clean!

Quote:
Originally Posted by Zero Cool View Post
Once you get cleared...I would mount the isolation transformer as near the room as possible to keep the secondary feed as short as possible. I would also think about HOW you are going to mount the transformer to reduce hum/buzz from being transmitted into the structure. Mounting on rubber pads or isolators is recommended. and use flexible plastic conduit as well.
Yes, the run to the upstairs outlets will be as short as possible; this was always the plan. However, I had not thought about acoustic isolation of the transformer... That is a good idea. I can do a wooden shelf with a rubber pad with a (some sort of) stone slab on the rubber. New rubber feet (it already has them) on the transformer housing itself is probably a good idea too.

Quote:
Originally Posted by Zero Cool View Post
and in the end you haven't done anything to reduce noise or stabilize voltage so i wouldn't go too overboard here.
Really? Not stabilizing the voltage, I fully understand (unless that power transformer has more going on inside than I think it does). But would this not be less noise than running 12-2 Romex across the house bundled with all the other 14-2 Romex feeding the rest of the house and into an outlet in the wall?

And would that not be better than having the stereo outlet daisy-chained with the other convenience outlets in the room? I'm trying to give the system the best shot I can. Sort of like carefully adjusting the speakers you have for the best image, or rebuilding the crossover, rather than replace the speakers all together- working with what you have and controlling what you can control. Am I wasting my time and money?
__________________
"When the world is running down,
you make the best of what's still around."
  Reply With Quote
Old 5th April 2010, 01:51 PM   #12
diyAudio Member
 
Speedskater's Avatar
 
Join Date: Sep 2002
Location: Lakewood, Ohio
If the outlet boxes are plastic, you don't need isolated ground receptacles. Switching from metal to plastic conduit might be an issue.

It would be good to have the convenience outlets on another circuit. With balanced power it's required.

At work we used Iso-Mode(sp) pads to mount vibrating equipment.
__________________
Kevin
  Reply With Quote
Old 5th April 2010, 05:11 PM   #13
diyAudio Member
 
Join Date: Feb 2010
Location: Back in CT!
The convenience outlets in (that half) of the room are (now) on their own 15A breaker (the other half of the room are similarly on their own 15A breaker). Those original outlets are (were) 1955 wiring practice, so they have metal boxes with the service ground twisted to the backside of the boxes, and no ground wire in the box itself. They also wired through (in on one screw; out through the other) each outlet which was disallowed some time in the 1970's I think. So, I am going in and putting a pig tail on each outlet and bonding the hot and neutral outside the outlet (rather than in and out of the outlet). It's a PITA, but at least I know it is right, and a failed outlet does not wipe out the chain downstream (which is why this code change came along). I am also installing new outlets as I go, so I know where I have been, and plugged-in stuff doesn't fall out due to weak contacts.

After looking through the white paper posted first (http://www.audiosystemsgroup.com/SurgeXPowerGround.pdf), I have made a decision for this installation.

I would like to run rigid conduit (the heavy pipe that is miserable to work with) grounded at the service panel as my service ground, but will more likely be running standard steel conduit (EMT) due to handling ease. Because of that, I may run a ground wire across each pipe junction to ensure a good ground path, but it is probably not necessary. This is why I think rigid is better (threaded on each end for a positive connection).

Within the pipe will be the hot, neutral and Isolated ground lines. I will run that to a metal box (or direct into the transformer enclosure) and then hard-wire to the transformer enclosure, which will use the service ground on its enclosure, but the IG will pass through to the outlet for the stereo.

Output from the transformer will go (as short as possible) to the stereo (20A, hospital) outlet, which will be in a metal box. The BOX will share the ground path of the conduit (the service ground- sort of retro-1955 style), the isolated ground will pass through the transformer enclosure (without contact) to the ground pin of the IG outlet as I mentioned above for a proper IG installation.

The thought process is that the service ground will provide a sort of 'shield' for my power line, while not allowing any induced noise to build up on the equipment ground at point of use (Isolated ground). All ground connections (and neutral) terminate at the same location within the service panel as required, which goes to the ground rod outside as well as the cold water pipe where it enters the house (the pipe happens to be very close to the service panel, and this ground was done when the panel was replaced- water pipe is actually copper too, because of the age of the house!).

One of the two outlets will have a line conditioner plugged in for analogue components; the other outlet will have another line conditioner for digital components. All the power will go through the transformer downstairs, but the point of use will be isolated from one another with power conditioners. (open to suggestions on those conditioners too!) I would like to use 1-rack space (maybe Furman?) conditioners and integrate them into the base of my (home made) equipment rack- maybe a sheet of Mu Metal over them so my power amp (on the bottom shelf of the rack) does not pick up any A/C noise (although that is a Counterpoint SA-220 which has copper plated steel for the enclosure).

The two 110 supply plugs will connect to the two outlets, and at the base of the rack (on the back side) each dedicated conditioner will have the corresponding components and/or their transformers plugged in separating analogue and digital.

I think that will get me as good as I can get without really ridiculous expense (such as balanced power; and I don't think the improvement will surpass the investment, and it seems to only be 'legal' for industrial applications only anyway).

How does that sound?
__________________
"When the world is running down,
you make the best of what's still around."
  Reply With Quote
Old 5th April 2010, 06:16 PM   #14
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
You should use EMT connectors that are compression type not the set-screw type. Grounding and shielding wise I think there are better.
Run bigger wires (#10) that #12 allowed.
Transformer secondary shall have one terminal grounded by NEC. You cannot have "floating" terminals and I won't recomend that either.

Last edited by SoNic_real_one; 5th April 2010 at 06:18 PM.
  Reply With Quote
Old 5th April 2010, 06:19 PM   #15
diyAudio Member
 
Join Date: Feb 2010
Location: Back in CT!
Good advice.

I like the compression fittings better anyway- I think they have a more 'finished' look once installed as compared to the set screw connectors.

#10 wire it is! The cost difference will be negligible between 10 and 12 anyway.

I'll probably run 3/4" EMT for plenty of pulling room...
__________________
"When the world is running down,
you make the best of what's still around."
  Reply With Quote
Old 5th April 2010, 06:30 PM   #16
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
I would still advice against the transformer, but hey... it's your choise.

Any transformer on the power path adds up some equivalent series impedance that will degrade the instantaneous current delivery capacity, will "dull" the attack and bass.
I can calculate the voltage drop on the secondary at the maximum load, if you have the data from label of the transformer.
And that is on a continous base, the transients will be much worse.
Only if it is big enough you won't feel that limitation. Something like 50 times the maximum power of your audio setup.
I did advice you for the AC/MC cables VS the EMT because the fact that there are twisted inside the shield and thats why they have lower impedance - good for transients. But you can "skin" some MC cable and use it twisted as it is inside the EMT.
Also probably both the primary and secondary have to be protected the way you are envision this.

Last edited by SoNic_real_one; 5th April 2010 at 06:36 PM.
  Reply With Quote
Old 5th April 2010, 06:38 PM   #17
diyAudio Member
 
Join Date: Feb 2010
Location: Back in CT!
I have to remember to get the specs off this thing; maybe a picture as well.

It is definitely big! No question there! Based on its original purpose, I always assumed those sort of things had been addressed; but I will open it up and see what's 'under the hood' on this beast...

If it is a simple 1:1 tranny, it probably is not worth using it sounds like. Since it was designed for the purpose of 'cleaning' the power for a large old computer, I assumed it would be adequate for a stereo rig... (I think it is 'Data General' branded but could be wrong- going from memory here!)
__________________
"When the world is running down,
you make the best of what's still around."
  Reply With Quote
Old 5th April 2010, 08:06 PM   #18
diyAudio Member
 
PaleRider's Avatar
 
Join Date: Nov 2003
Location: home
If there`s one thing I`ve learned; remove all stranded wires, signal or power. You can do a simple test to get a clue by running one stranded and one massive powercable, lets say 20ft long.

No cleaning-trafos survives in my system, even if I get them custom made like all my trafos. Everything that ears dynamics are banned, first of all multicore wires.
  Reply With Quote
Old 5th April 2010, 08:12 PM   #19
diyAudio Member
 
Join Date: Feb 2010
Location: Back in CT!
OK.

I built a passive preamp years ago from the Stereophile design and that was all solid cored wire when I built it. Unfortunately, I overheated the buffers installing them, and it has sat unfinished for years...

At that time, I believed solid was the way to go for signal; power was not such a hot topic as it seems to be these days.

Solid 12ga copper power leads to each component sounds particularly unpleasant to try and work with! Is this what you use?
__________________
"When the world is running down,
you make the best of what's still around."
  Reply With Quote
Old 5th April 2010, 09:07 PM   #20
DaveG is offline DaveG  United States
diyAudio Member
 
DaveG's Avatar
 
Join Date: Feb 2007
Location: Grease
don't think think was mentioned yet...why not run a dedicated 240 volt "dryer" circuit with standard large 3-prong receptacle. Can your power conditioner be configured for 240?, plus you have all sorts of high current wiring options after it passes inspection. Maybe you can have the line run with flexible metal clad wiring-I forget the brand name at the moment. That style is used in garages and such for added protection. Get the large conductor size with 4 wires, so one is a ground and also ground the metal clad jacket. And I believe all of that may be a more or less a standard dryer run.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
help in adjusting Vout in the power supply of the "Brute force in a line stage" by Er jarthel Tubes / Valves 9 30th May 2006 07:47 AM
"log line" and "pressure chamber" skrivis Multi-Way 0 21st April 2005 03:55 PM
Your ideal "ChipAmp", unlimited budget loong Chip Amps 23 12th February 2004 11:56 PM


New To Site? Need Help?

All times are GMT. The time now is 04:31 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2