10 awg Romex with Hubble or PSAudio power port. |
Note that the world-wide price of copper has about doubled in the past year.
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I use Accustic Revive inwall cable which uses solid core 10 g wire for my digital front end and 8 g solid core for my amp. |
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I climbed my utility pole in the dead of night to run dedicated twisted effective 7awg to the transformer and was blown to bits. I am a ghost sent here to warn you not to try it. |
Glen: You haven't been looking too well then. While Albert shows up from time to time in threads, i know that he's doing more reading than posting. As for me, i never shut up. Then again, you probably already knew that : ) Sean
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Look who's talking Albert and Sean. I haven't seen you guys in the forums in months. By the way great pics of CES this year Albert :^)
I've been real busy fixing up my house, but I still browse Audiogon on a daily bases.
Got to go, I'm doing my lay out for a tile floor in the entry way
One thing I didn't mention; the maximum ampere rating of a conductor (table 310-16 of the NEC) is just the starting point in calculating the correct size. There are other factors that have to be addressed which will lower the ampere rating of a conductor (i.e. ambient temperature, number of wires in a conduit, length of run)
Glen |
Highend64: I think that you are correct. Due to the air gaps located between the stranded conductors, solid cabling of the same gauge offers slightly more material to pass power through than an equivalent stranded version. I could be wrong here, but that's what i remember. Sean
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Glen, dosen't solid have more surface area than stranded wire? |
Albert: I think that Glen's been playing "sniper in the weeds" with us. Like you, i'm glad that he decided to give Audiogon another shot : ) Sean
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Good to see you posting again Glen. |
Glen: Thanks for posting what you did. I had always thought that 10 gauge in conduit was rated for a max of 30 amps. Given that most of these ratings are running "on the edge" or even "slightly over the edge", i've always found that going at least one gauge heavier than what they recommend helps maintain steady current flow with minimal voltage sag. That's why i said that 8 gauge was good for 30 and "maybe" 35 amps. Sean
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I hate you guys, why, because it's Sunday night (my day off) and I just pulled out my NEC code book to check something.
Table 310-16 states that a #10 conductor THHN has an ampere rating of 40 amps. A #10 tw (Romex) has an ampere rating of 30 amps. Regardless of these ratings there is a note on this table (240-3) that say's the overcurrent protection shall not exceed 30 amps for a # 10 copper conductor.
Buy the way stranded and solid conductors have the same number of circular mils and thus are rated the same. |
I don't know what handbook you are reading, but try passing 50 amps through ANY 10 gauge wire for an extended period of time and see how hot it gets. Ratings like that are foolish at best. 50 amps of current through 8 gauge will show a very definite temperature rise. As far as i'm concerned, 8 gauge is sufficient for 30 to maybe 35 amps of current. It will obviously pass a LOT more than that on short term demand, but it is at the times of high demand that you want the least sag possible. That may not agree with anything else you ever read, but then again, i'm not willing to accept the low standards that the industry uses. Sean
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Glen, if 10/2 solid romex cable were run, wouldn't the cable withstand 50 amps max? According to my handbook, a 10 awg solid wire can hold 50 amps max while a stranded 10 awg can only hold 23 amps. Also, do you think is a good idea to use 10/3 20 or 30 amp twistlock connectors than a 20 amp Edison? ThanksAlfredo |
Solid conductors are prefered in any given situation except for situations where flexibility or repeated stress is of concern. I know of "honest" cable manufacturers that will agree with this statement even though most of their products are of stranded design for reasons of flexibility. Twisting reduces inductance and increases capacitance, which helps lower the noise floor and increase the rejection of RFI. Combining the two offers the most benefits with the least drawbacks of any other approach.
As a side note, use the heaviest gauge wires that you can use within reason. 12 gauge should be considered a minimum for any type of A/V installation. Sean
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Twisted conductors cancel RF. I use them all the time in low voltage control work though normally not for that particular reason. |
I notice that some of you have used #12 THHN stranded, and others #12 gauge solid core twisted. Can someone explain the rationale for choosing either? |
Budrew:
IMO, the advice you are receiving on this thread is spot on. If you search the forums, you will find lots of threads that are covering this subject, but the link that Albert provided is as concise and pointed in terms of your concerns as any you are going to find. Gotta agree with the others who recommend Alberts ports....they are a terrific quality outlet and offer big bang for the $. You will find some conjecture regarding the number of circuits that are appropriate. Some feel that more than one circuit leads to a higher chance of ground loops. In my experience, overkilling the ground system goes a long way toward solving this problem at the same time as enhancing safety.
Glen is an electrician by profession and IMO is the resident AG master on this subject. If you follow his plan to the letter you will not be missing much. I am a DIY person and have installed circuits in line with Glens recommendations with the exception of not having yet put in a sub-panel. In my experience, quality dedicated circuits have given me the biggest bang for the $ of any change I have made. |
Thanks KT88, I'll paypal you $20.00 right away :^). I've been wanting to come over and here those new speakers by the way.
Sean - The first 200amp main is just a breaker at the meter nothing else. |
Last Summer I had my homes 40 year old 100 amp main upgraded to 200 amps. A 100 amp sub-panel was added for my 2 channel audio room with 8 dedicated 20 amp circuits. Glen's construction methods and material suggestions as listed above were applied. My City signed off the electrical permit with no problems. Now my tubed monoblocks with Avalon speakers wrap their dynamic sound around me like never before. Glen has great knowledge of electrical as applied to our audio hobby. |
Dedicated 100A subpanel for theater room. All equipment on one leg, lights, utility outlets, etc. on the other leg. Standard to code 12-2 Romex for 20A ciruits. PS Audio Power Ports for PreAmp, Amp, and CD player, hospital grade isolated ground for the balance. |
Glen: If you don't mind me asking, what is the second 200 amp sub-panel for ? If i read this right, you'll have a 200 amp main feeding a 200 amp sub-panel feeding a 100 amp sub-panel. The 200 amp main would appear to be for the whole house and you mention using the 100 amp sub-panel at / near your audio system. Where does the second 200 amp panel come into play in all of this ? Sean
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Wow this thread is taking off, here's my take.
I just bought a "new" old house (with a view of course) :^)
I currently have a 100-amp service. I'm going to change that to 200 amps real soon.
Then I'm going to take out the existing sub panel (Approx 50 feet away) and upgrade it to a 40-space 200-amp sub panel.
I'll run a 2" conduit between the service and the sub-panel.
Then I'm going to pull two new hots, one Neutral (4/0 THHN cu rated for 200amps) a dirty ground and an Isolated ground.
I'll set both panels up with isolated ground bars, add a ground rod, replace the ground clamp at the water main, and run new bare copper continuous to both the ground rod and water main.
Then I'm going to tie the water and gas together with a jumper and two ground clamps, this I will do at the H/W/H for convenience and yes it is legal in CA.
After rewiring the new 200-amp sub panel I'm going to add another 100-amp sub panel on the other side of the house near my listening room (approx 150' away)
I will run a 1-1/4" conduit from the 200-amp sub to the 100-amp sub-sub. Then I'm going to size the wire for 120 amps (THHN cu) but only install a 100-amp breaker.
I will add another isolated ground bar at this panel.
Then I'll take six dedicated 20-amp circuits (#12 THHN Stranded) up to my listening room. Each with it's own neutral plus one isolated ground and one dirty ground. I may add a drain wire too (That's an idea Albert gave me awhile back that I found intriguing)
I'll be using industrial grade Hubbell I.G. 20 amp receptacles (Ground up of course) at my gear. That should get things rolling in the AC tweak department wouldn't you say.
OH, and yes I am an electrician and personally "Bang for the buck" this is as good as it gets IMO. |
Craig,
I consider $3/ft for cryo'd Romex excessive!...and still believe that better dielectric DOES matter. |
Dedicated 100 amp sub panel just for audio with three 110 volt and one 220 volt dedicated circuits.
I run THHN stranded # 10 doubled up for all hots, grounds and neutrals which gives me around 7 gauge conductors. Very nice for my amps. I use the 220 volt line for my power plant and two 110 volt lines for each amp and the last one for my Logans. I have found the two 10 doubled up is much better than single 10 gauge, I also twist the two conductors about 3-4 times per foot. Dedicated ground rod and all breakers and wire treated wit pro gold.
My next upgrade will be using two 12 gauge stranded conductors twisted around one 10 gauge solid conductor and giving it about 3-4 twists per foot, this should yield me about 5.5 gauge.
The way my dedicated lines are config, the system is dead quiet, the best it's ever been in regaurds to quiet, noise floor, blacker back ground, etc...
I think the dedicated sub really helps as nothing else is in the sub and everthing is in phase which is something that people over look as it does make a difference! Happy wiring! |
Garfish ( and others using similar set-up's ): Even if you have four 20 amp breakers, you do realize that these are being fed by a single 30 amp breaker. As such, you are limiting the total current capacity of the sub-box to 30 amps total, regardless of how many breakers and their ratings in the secondary box.
From my line of thinking, you should have had the electrician tie the secondary breaker box into the mains. This would bypass the 30 amp breaker and allow you to pull as much as you needed from the mains. The only limitation at that point would be the master breaker on the smaller secondary box. In order to do this though, you would need to replace the 10 gauge wiring that goes from the AC mains to the secondary box with something heavier.
In my opinion, 8 gauge is sufficient to handle 30 amps continuously, so you would need at least 4 gauge for an 80 or possibly 100 amp service. That is, if you were ever going to pull that much power on a steady-state basis. The reason that they can get away with using smaller gauged wires in most installations is due to the fact that most people aren't pulling that hard on all of the circuits at the same time, so momentary overloads are not that big of a deal.
Please bare in mind that i am NOT a certified electrician and building / electrical code may vary from location to location. As such, the info that i or anyone else posts to a thread like this should always be verified at the local level prior to taking it for "gospel" and acting upon it.
As i've mentioned before, PLEASE correct me if i suggest something wrong, as this is NOT just a matter of opinion on stuff like this. It can be a matter of life, death and /or personal property loss. None of these are matters where mistakes should be allowed to slide as far as i'm concerned and those that are knowledgable and / or skilled professionals should chime in ASAP in such cases. I would much rather have a boot to the head than be responsible for possibly helping someone to kill themselves or harm their gear. If you don't know what you are doing with electricity and wiring, DON'T try this stuff on your own. Sean
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PS... Unlike 9 volt batteries, you should never put AC wiring into your mouth and touch it to your tongue to see if it is live : ) |
Jmcgrogan2....The uninsulated ground wire goes without saying in X/2 or X/3. With either voltage you need only power wires (plus ground). With 110 it's 110 and neutral (which is nominally ground). With 220 it's +110 and -110 so that you have 220, line-to-line (plus ground). |
I used 10/2 romex. I would be cautious, check with your insurance company, about using something that does not meet or exceed your building codes. If it causes a fire you could be liable.
Chuck |
I just upgraded my ded. AC system using all Virtual Dynamics cryo treated wire, breakers, and Hubbell 5362 outlets. 10/4 BX from Main panel to sub-panel $3./ft. (actually 10/3 w/ ground), and then 10/3 (10/2 w/gnd) from sub panel to outlets. 30 amp cryo'ed breaker in main panel, and four 20 amp breakers in sub-panel. All this is now broken in and sounding excellent-- sweet, mellow, live, and most of all very, very natural. At $3./ft. for the wire, I did not consider it excessive. This has been a very worthwhile upgrade. Good Luck. Craig |
Eldartford, 10-3 has four conductors as Glen stated. The fourth leg usually is used for running an isolated ground. You would also need to have a receptacle capable of using that feature though, like a PS Audio Power Port. My electrician shook his head and declared it overkill. I told him many would think much of my system is overkill.
Regards,
John |
Check out the Virtual Dynamics site. The have cryo'd circuit breakers and inwall wiring.
http://www.virtualdynamics.ca/products/HWS
I haven't tried it yet, but I will. |
If you can find heavy gauge ( at least 12 with 10 being preferred ) twisted pair, that would be excellent. I know that Anixter used to stock 12 gauge solid core twisted pair. This design will lower inductance, especially if you've got a long run. It is bulkier and harder to pull through conduit, but it should offer some benefits.
While i don't know how "lawful" this is in various States, you might want to run this by your electrician. You can use the conduit as ground and isolate it at the breaker box. Install a dedicated ground rod for the audio system in very close proximity to the ground rod that is used the mains and ground the conduit to the secondary ( audio ) ground rod. The two ground rods should be tied together electrically and weatherproofed once you have very solid connections.
Since the rods are tied together at the point of Earth ground, noise from the rest of the house will be shunted at that point. This is especially true since you now have two ground rods, giving you twice the conductive area to ground. Since electricity typically prefers to take the shortest, lowest resistance path to ground, any type of noise coming from the house / AC mains would be shunted at the point of connection.
The system now has a dedicated ground AND is connected to the rest of the house in a manner that should be both legal ( building code & home-owners insurance ) and harmless in terms sharing a common ground. On top of that, your AC feedline to the audio system is basically a 100% shielded low inductance twinaxial cable. This saves you from having to run the third wire and leaves more room to pull the twisted pairs through. Sean
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Just want to clarify that you don't count the ground when buying romex cable. 10-2 is a hot,neutral and ground. If you buy 10-3(2-hots,neutral and ground) you could use one of the conductors for an isolated ground(I.G.) in theory. |
Sorry and thanks, I meant 10/2. |
1. Why the -3? (10-3 instead of 10-2). With 10-2 you still get a third conductor for ground.
2. If you go to 240volts your wire size can get smaller because fewer amps are drawn. 12-2 at 240 volts is better than 10-2 at 120 volts, and, depending on how long the run is, will save a few bucks. |
10-2 or 10-3 BX cable not rOMEX not code in NYC. |
This is the same cable that SignalCable uses for their MagicPower cable. I had it and was not impressed as much as I am with the ChrisVH series cables. IMO. I would just use romex, but can anyone chime in who has used this carol cable vs. romex???
Thanks! |
Hi, Albert. It is obvious to me that I actually posted first. :)
I'm looking at the Parts Express catalog #21 on pages 55 and 141 where they have a heavy duty 10/3 power cable that is 99.9% OFC. However, it is stranded and I thought it was solid core.
Their price for this is $33.15 for 50 feet. But there should be a few other places to check for quality solid core 10ga. but not many.
I bought my solid core 10/3 99.95% OFC house wire from a friend who had quite a bit of custom made for his new listening room which has perhaps 20 or so dedicated lines throughout the room.
Hope this helps,
-IMO |
Stehno, we must have been posting at the same time. If Parts Express has 10 gauge OFC copper for about the price you quote, it must be considered as an option. I can't imagine better quality copper NOT providing superior results.
Wish I had known when I ran my dedicated lines. I may consider upgrading later. |
I have great sound and I am using Romex brand 12-2 and 10-2.
Other option is 6 or 8 gauge wire and 240 volt, provided your amps may be switched. I got a small but very noticeable improvement both times amps were run in this configuration.
Even with 240 and several 120 dedicated lines, your cost will likely be less than buying audiophile power cords.
No question audiophile power cords are beneficial, but dedicated lines are a huge bang for the buck, even if you later decide to go for aftermarket cords as well. |
10/3 should be sufficient for all lines and as mejames says, would definitely meet or exceed code.
Look for an aftermarket 10 gauge solid core 99.95% OFC flavor.
PartsExpress.com used to carry such a product for about $30 per 50ft. roll I believe. You can certainly get more exotic than this type of house-wire, but this should level of quality would suffice.
And is much better alternative to the Romex brand found at home depot.
-IMO |
10/3 would definitely meet Code. |
