We had our meeting with our new house electrician Tuesday. All went smoothly. I want to thank all the posters that helped make that happen. With special thanks to Al (almarg) and Jim (jea48). Both went above and beyond in terms of help and effort. In fact, several of Jim's PM communications were specific to my circumstances and he was amazingly specific; taking time out of several of his days to help a fellow audiophile. My hat is off to you both? Cheers, -Mike
Whole House Mains Wiring -- Ping: Jea48 (Jim) -- & ALL Others for your HELP!
I had the following PM discussion with member Almarg. As you can see he -- as always -- was quite helpful! However, upon my suggestion to post our conversation for others to see and perhaps learn, Al readily concurred, but suggested for the questions that he couldn't address, he referred me to Jim [Jea48].
It should be noted that I drug my Atma-Sphere amp manufacture, Ralph Karsten into this conversation via email. As generous and helpful as he always is, he too helped a bunch. I haven't copied his single email because the below is complex enough, without adding more.
My hope is that where my assumptions are questionable or for my questions, others will respond.
Our new house's rafters are about 50% installed, so the other trades will be in soon. And I will have to soon inform our electrician of our needs. But I don't want to request something that isn't needed. More IMPORTANTLY, I don't want to MISS something that is NEEDED! So your help in checking this thread is greatly appreciated!
NOTE: I've listed our conversation as Audiogon would -- the most recent post last. So, the real important part for me, is getting answers to the set of questions I asked towards the bottom -- Today at 20:28!!
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mrmb (you)
January 27, 2018 23:49
Thanks Al! That's what I was seeking.
Speaking of electrical noise/hum, I just found a Martin
Logan article speaking about pre-wiring
https://www.martinlogan.com/learn/faq-prewiring-a-home-theater.php.).
It addresses one of my other concerns about inserting
multiple dedicated circuits in one room. They advise to connect all
outlets/circuits with the same ground wire. I've previously read that ALL audio
components should be connected together -- i.e., on the same dedicated circuit.
If one didn't tie 2-dedicated circuits together by using the same ground, I can
see why I've seen that advice.
Have a great remainder of the weekend AL. And thanks for
sharing your expertise on Audiogon and in this PM. It's appreciated!!
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almarg
January 28, 2018 13:37
Hi Mike,
Thanks for sending the link to the article, which I hadn't seen before. A couple of comments on it:
1)As you appear to realize, the benefit of the single ground wire approach they advise is that it would minimize or eliminate any differences of potential (i.e., voltage) between the safety ground connections of the outlets for the various dedicated lines, and hence any differences in potential between the chassis of components that are interconnected in the same system but are powered by separate dedicated lines. Which in turn will avoid ground loop issues that might otherwise occur.
2)If the electrician indicates that such an approach would be problematical, due to either practical considerations or code compliance issues, using 3-conductor Romex (e.g., 12-2 with ground) for each of the dedicated lines should come close to accomplishing the same thing. And could very conceivably provide results that are just as good.
In 3-conductor Romex the safety ground wire is symmetrically placed between the hot and neutral conductors. Therefore voltages that may be induced into the safety ground conductor by the magnetic fields surrounding each of the two current carrying conductors [current flow in a conductor produces a magnetic field around that conductor] will tend to cancel, since the fields produced by the two current carrying conductors are in opposite directions.
For further explanation see pages 31 to 35 of the following paper, which was written by a renowned authority on such matters:
https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf
Best regards,
-- Al
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mrmb (you)
January 28, 2018 20:28
Hello Al,
RUN LENGTHS/BALANCING:
I did recently find elsewhere as you suggested, that using 12/3 was a prudent approach, but thanks for seconding that approach.
We talked about Martin Logan’s single ground wire
recommendation. And you mentioned that using 12/3 (verses 12/2) may well
compensate, if code prevents the implementation of ML’s plan. I suppose if code
allows the M/L single ground wire approach and then 12/3 is also used, that
would be icing on the cake!
Because it’s a breeze to do while the walls are open, I
believe I will put 2-20amp outlets in the most important room – the 2-channel
one (just in case)! Residing therein will be: 1) Atma-Sphere MA-1 monoblocks; a
Lampizator Golden Gate DAC and 2-Soundlab M1PX stats.
For now let’s ignore the Soundlabs, which will be about 7
feet from the rack and that wall’s outlets, and thus, probably on their own 15amp
circuit. Would you recommend that the Atma-Sphere amps be plugged into 1 of the
dedicated 20-amp outlets and the Lampizator plugged into the 2nd. 20-amp
circuit? Or would it be better to plug all 3-pieces into the same 20-amp
circuit (plugging the Lampizator into an additional receptacle on the same
circuit)?
Ancillary to the question of what component(s) should be
plugged in where: Would there be any sonic downside to installing a Wall-Switch
for the 2-Soundlab’s dedicated line (and its ganged outlet on the opposite side
of the room)?
That is, would a Wall Switch be some sort of sonic negative;
because it was a part of that circuit (sonically deducting a positive, or
adding a negative)? And referencing the Martin Logan’s single ground wire plan:
I’m unsure if we tied 3-dedicated circuits together (both 20-amp ones and the
15-amp Soundlab one) with a single ground, if a Switch would prevent that
process from being implemented? Or would a Switch somehow negatively affect the
“single ground logic”, or simple be too cumbersome to install?
Lastly, if code will allow M/L’s method of using a single
ground on all dedicated circuits for my room, it may be difficult to implement
because of the distance the Soundlab's (7-Feet) are from the front wall
outlets. Especially when considering that the Soundlab’s outlets will be
19-Feet from each other – on opposite sides of the room.
My concern may be unfounded, because being the neophyte that
I am; I can’t envision how to implement a single wire ground for 3-dedicated
outlets as far apart as mine will be. And overall, I wonder if would be good
enough (in audiophile terms) to simply install 3-dedicated circuits and not be
concerned with using the same ground for each? However this may be confounded
by the fact that folks have suggested that if multiple dedicated circuits are
used, one should make the wire length for each one as close to the same as
possible. Without rolling-up and storing several feet of cable (in the walls or
at the panel) for the circuits longer that the other’s, this would be all but impossible.
I apologize for my hyper-granularity or should I say my
“analness” regarding this wiring issue, but that’s sort of the definition of we
audiophiles isn’t it? At any rate, I appreciate your assistance in a topic that
I’m flying blind on! After we’re all said and done here, for others to gain
from your teaching, I would like to post our communications on Audiogon as long
as you’re amenable to same. That’s the beauty of forums, many sharing/learning
from ONE!!! But I digress…..
WIRE:
The plan is to specify Southwire’s Romex ® brand of Solid Core (vs stranded) wire – is Southwire Solid Core also your recommendation? But I’m confused about the type of Romex ® to use. I’ve seen various ones: with “XHHW” recommended over “THHN”, but also “NM” recommended. What say you?
WIRE GAUGE, MULTIPLE OUTLETS:
Additionally, I've found a piece posted by MSB to be informational. As you can see (http://www.msbtechnology.com/faq/how-to-wire-your-house-for-good-power/) their thesis is that gauge size is of utmost importance! I’ve found some disagreement relative to whether 8 gauge wire can be installed in an outlet or not -- your opinion? At any rate, can an electrician pull 8 gauge to the audio room and terminate it in some sort of junction box and go from there to my audiophile grade outlets? And then, is there any downside to ganging several outlets from one dedicated circuit? In my home theater area, rather than multiple wall outlets, I’ve found it more advantageous to use a power center such as the Furman Elite-20 PF I’m presently using. It has a video and a sonic benefit, plus I find DC Triggers to be useful. So, unless you believe ganged outlets are better than a Furman (et al), I won’t have the electrician install anymore outlets than I think will be needed when using a Power Center.
PANEL-TO-PANEL WIRE GAUGE AND CONNECTION METHODOLGY:
Should I recommend a specific wire gauge or type for the electrician to use BETWEEN the main 200-amp panels and the sub-panel? Should I ask the electrician to use a specific method to use to tie these panels together? One forum poster advised: “running one large wire from the very top position in the load center on the leg with the least number of noise-generating devices to a sub-panel”. Would this be your method?
BREAKERS:
I also found the following discussion from PS Audio (http://www.psaudio.com/ps_how/how-to-install-a-dedicated-ac-line/). It advised that 20-amp breakers should be used “for even the lowest draw source equipment feed”. I took that to mean that although the circuit may be less than 20-amps, that a 20-amp breaker should be used. Is that what you would suggest?
LOAD CENTERS:
So, my present plan for the 2-channel room (mentioned previously) is to install 2-200 amp panels and a 60-100 amp subpanel for the 3-A/V areas (to get it as close as possible to 2-channel audio room – is this your preference?
Speaking of load centers, I’ve found several positive
mentions of Schneider’s Model: “Square D QO” Panels (the “QO” Model with copper
plated busing). Does QO Square D model work for you?
GROUND ROD:
I’ve read rather lengthy dissertations on this subject. Not being interested in getting into the weeds here, is there a material, length and methodology you would suggest using here?
SERVICE:
And lastly, should I even be concerned about the wire/cable used for the service drop or service entrance? NOTE: Service will be buried.
IT’S ABOUT TIME….THE CONCLUSION:
Whew, I can’t tell you how much I appreciate you wading through all and helping with all of this!! It’s all but impossible to find folks educated in this subject such as Electrical Engineers and Electricians who care about the details we audiophiles do! So, I consider you a wealth of information on the subject form your previous responses to my questions but more importantly, from the number of posts and volume of information that you’ve posted on Audiogon and I’m sure elsewhere!!!
Be well and take care,
-Mike
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almarg
January 28, 2018 22:06
Hi Mike,
Thank you again for the nice words.
I should have been more explicit when I referred in the previous communication to "3-conductor Romex (e.g., 12-2 with ground)," and subsequently to "3-conductor Romex." My reference to three conductors included the ground conductor, so I was referring to "12-2 with ground" and not to 12-3. The additional "hot" conductor in 12-3 would serve no purpose in this situation, and if that conductor were used to carry a current the benefit of the symmetry I referred to between the current conductors and the ground wire in 12-2 would likely be negated.
My suggestion of 12-2 Romex as a potentially suitable
alternative to ML's suggested configuration was in contrast, for example, to
using conductors within metal conduit, which as explained in the reference I
cited would be much more conducive to ground loop issues. Especially when
multiple dedicated lines are used to power the components in a single system.
Regarding your first question, my guess is that it would be
best to put the amps and the DAC on separate circuits. I say that in part
because various comments I've seen Ralph provide over the years lead me to
believe that his designs are less susceptible to ground loop issues than most,
and consequently there is unlikely to be any downside from keeping the amps and
the DAC with its potentially noisy digital circuitry on separate dedicated
lines.
Regarding a wall switch for the power to the speakers, I
don't see that as being a negative in itself. However as you alluded to the
considerable distance between the various outlets does sound like implementing
the ML approach would be cumbersome at best. And perhaps more significantly the
considerable length of the ground connection between some of the outlets may
negate a lot of the benefit of that approach. So perhaps just using "12-2
with ground" Romex in the normal manner, for each of the dedicated lines,
would be simpler, more practical, and provide results which are just as good.
Regarding the suggestion of keeping the lengths of all of
the dedicated lines the same, which I too have seen stated a number of times
and which the ML writeup implied is desirable, FWIW I am not a believer in
that. In nearly all applications the different lines would be carrying very
different amounts of current, and correspondingly their conductors would be
surrounded by magnetic fields having very different strengths, resulting in
very different amounts of current being induced in the ground wire. Not to
mention that voltage drops in the hot and neutral conductors would be very
different. So I don't see why keeping all the lengths the same would provide
any benefit.
Regarding posting our communications in the forums, that
would be fine with me. If you were to do so, or at least start a thread with
some of your questions, chances are it would catch the eye of Jea48 (Jim), who
is by far the leading expert at Audiogon on electrician-type (as opposed to EE)
matters.
And for that matter, Jim would be the best person to address your questions about NM-B vs. XHHW vs. THHN, use of 8 gauge wire (which I suspect would be extremely difficult to work with, as well as probably being overkill), and most or all of your subsequent questions.
Regarding the question about PS Audio's statement that "we recommend you use a 20 amp breaker for even the lowest draw source equipment feed," though, I can say with certainty that it would be both unsafe and a code violation to use a 20 amp breaker on a circuit which "may be less than 20-amps." In other words, if a 20 amp breaker is used the outlet must be a 20 amp type and the wiring must be 12 gauge or heavier. What they no doubt meant, as you probably realize, is that even if the equipment powered via that line only draws a small fraction of 15 amps, they would still recommend a breaker, outlet, and wiring rated for 20 amps. Which would have no downside, and I suppose might provide at least a small benefit in some circumstances.
Best regards,
-- Al
56 responses Add your response
Thanks Frank! You mentioned a Central Vac. among other neat things one can do when building a home. Indeed, we have installed one in each of our last 2 custom builds. And are doing a 3rd. one in this build. This time we're doing the Hide-A-Hose (yeah, I know that's what she said) rather than 5-inlets, only 2, and the system really looks convenient. |
If I was building a home today I would try and have least 4 dedicated circuits for the stereo equipment alone. Each duplex outlet would be a hospital grade receptacle. They are available at electrical supply stores. They're colored orange. I have many outlets behind my gear but only 2 are dedicated lines. They are 10/2 romex protected by 30 amp breakers. When I installed these many years ago I felt it made a bit of a difference. The breakers are to protect the circuit and a 30 amp breaker goes with #10 wire. Anything larger than 10 awg won't fit under the receptacle terminal screws. 10 wire won't be easy. This is definitely overkill but I like having plenty of power available when the equipment asks for it. THHN is the wire used in homes and many other applications. There are many types of insulation as there are environments in which electrical circuits are used. If you go with a subpanel be sure to only bond the neutral at the primary panel otherwise you'll get a ground loop hum. For the digital conductors a conduit raceway between your gear and its source would be nice. Preferably 2", but smaller would be ok. This would make it easy to upgrade when something better is invented. As for the rest of the receptacles in your new home, I would recommend that the electricians pigtail ( with wire nuts) and have the wires wrapped around the screws and not stuck into the holes in the rear of the receptacles. I am not a fan of those push-in devices that are being used today instead of wire nuts. They're probably the main reason why arcfault breakers are now being required. I replaced and rewired all the receptacles in our home a few years ago and feel much better that I did. This is just my suggestion and I hope it's of help in your construction project. There are a lot neat things you can do when building a home if you have the budget to do so. Central vacuum, security system, standby generator, dedicated circuit in the kitchen for a commercial microwave to name a few. Best wishes, Frank |
@mrmb, Dedicated 120V branch Circuit. A dedicated 120V branch circuit is a circuit with a dedicated, Hot conductor, neutral conductor, and safety equipment grounding conductor. Usually the circuit is dedicated for a piece of equipment or appliance. Example, a manufacture may require a dedicated 120V 20 amp circuit to fed his equipment. Or the manufacture may have a cabinet with several pieces of equipment installed within the cabinet and he will require a 120V 20 amp dedicated circuit. A true dedicated branch circuit, (an accepted electrical industry standard), does not share the same raceway, conduit, or cable assembly with any other branch circuit/s. In your case you want to use dedicated branch circuits to power audio and video equipment in an audio room and HT room. The dedicated branch circuits are meant to supply power to audio and video equipment. General convenience 120V wall duplex receptacles outlets in the two rooms will be fed from a convenience outlet branch circuit. You asked how many receptacles you can install on a 120V 15 or 20 amp branch circuit? Going from memory, NEC, in a residential dwelling unit you can install as many as you want. With that said, AHJ has the final say. Jim |
The need for multiple circuits is well documented in the AV world. A high quality AV receiver can draw 12 to 15 amps when playing a movie at what most people consider a realistic listening volume. If you consider a high end system with a separate power amplifier you will need 15 to 20 amps just for the power amp. A 5 channel 200 watt per channel power amplifier will draw 15 to 20 amps at higher powers. It will only do it for a few fractions of a second at a time, but if it cannot get the current, it will clip, and not be able to do the job you expect out of it. I will admit that I assumed you were talking about quality high end equipment because you were talking the time to research on a sight such as this. Any of the high end home theater equipment manufactures, dealers or professional installers will verify what I am saying. Mcintosh, Levinson, Krell, and Classe all recommend dedicated circuits for their power amps. Try this; if you have a laser printer in your home office, turn on the lights and print something. If the lights flicker, you are seeing the result of not having enough capacity. A typical home office laser printer draws 12 to 15 amps when it prints. Most home offices have multiple outlets all daisy chained together on one circuit breaker. |
For me this would be overkill - not running a factory here. Many audiophiles use fancy power conditioners anyway. I have one dedicated 20 amp circuit with vintage Macintosh equipment, bi-amped, etc. Of course, if I added several toasters and a hairdryer, I would be in trouble. BTW, we should be clear about the “neutral” white wire, and the conduit, or third wire (“ground”). Open your service box and you’ll see that the neutral is connected to a strip that is fastened to the frame of the box, i.e. having continuity with the conduit. Then, there’s a strap from the ground that goes to the cold water pipe (there has to be a jumper connecting the pipes on both sides of of the water meter as well). Currently, code requires ground connection to a six foot solid copper pipe pounded all the way into the earth. It’s all about safety - throughout the house the neutral is not to carry the ground, or vice-verse. Remember that it’s not just the black wire to watch out for in a live, loaded circuit. If you come between the neutral and the ground, or cut the neutral and hold both ends - you’ll complete it and get shocked. Having said all of that, it’s not difficult to add your own breakers to the service box and wire it all DYI, if you’re comfortable with electricity. Check your town’s code. Mine gives the option of letting the home owner wire his own house (only), after taking a special test, of course. The inspector comes to check it afterwards. |
Have to agree with fisher_400 here, as after moving in to our recently completed house, I saw the need for a dedicated 20A circuit for our “entertainment centre”, which housed telly and all the stereo gear, incl. powered sub. Installed a 20A breaker in service panel, then ran 12/2 w/grnd. Romex cable, and parallel-wired via junction box to two commercial-grade 20A receptacles, and have enjoyed clean, noise-free operation ever since. Also of note, I did install an isolated-ground, dedicated 15A circuit for home office use to support PC, printer, and telecom/network peripherals, with hospital-grade duplex receptacle plus power bar...never had any adverse effects following repeated power outages, electrical storms, etc. However, would be overkill for hi-fi equipment support, IMHO. |
I mentioned "ganged outlets" in the above post. I believe -- with "believe" in quotes -- I understand the term. If a dedicated line is involved, "ganged outlets" means several outlets (receptacles) connected to that one dedicated line. Have I kinda' got it? If so, does that mean that the dedicated line would go back to a single phase or leg of the load panel? If so, this then would define it as a "dedicated" line? And if we're NOT dealing with a dedicated line, multiple outlets in many different locations could be ran off any one leg/phase of the panel? With equally as many "ganged" outlets (as the load would permit) from the same leg/phase, because they are all emanating from the same load panel leg/phase? Man, if any, or all of this is remotely correct, I would be surprised. If I have some or part of it correct, how many ganged outlets should be/could be ran from a dedicated circuit? I suppose that depends upon the circuit's amperage and any resulting load would need to be estimated to determine that answer? Nevertheless, for our audio/video needs, what would be an average &/or maximum number of outlets (before a too negative voltage drop were encountered) that could ran/connected from one dedicated circuit? |
Quote: hig3: Also plan on at least one 20 amp circuit for your analog sources, and one for your digital sources. You should also have a separate circuit for your video components and displays. And one for your control system, if you will be using something like Control 4 Crestron. After just deciding to install a 120" projection system
adjacent to the 2-channel Soundlab room, your suggestions help to decide how to
manage the dedicated circuits. Having all -- Oops, I accidently prematurely hit
the post buttton -- so I will continue: It also takes the concern off the table, of keeping appliance motors, dimmers and other nasty's on the different panel position/legs/phase, and at bay. Quote: Hig3: Have the electrician run 10 gauge wire if you can afford it, and it is allowed by code… After finding the aforementioned and linked to MSB article (http://www.msbtechnology.com/faq/how-to-wire-your-house-for-good-power/) ; I decided to run 10 gauge to all A/V locations.
In this context, do the terms “phase” and “leg” mean the same? I’ve seen them used interchangeably? Quote Ottuso: i wonder if an electrician would install 3 circuits with a common ground? With 2 circuits from vertically adjacent panel slots the hots would be out of phase - okay for a ground of the same wire gauge. 3 circuits would put 2 in phase. Perhaps, one could use 12 *[EDIT: 10] gauge for the hots and 8 for the neutral? Ask... Being ignorant in panel wiring techniques, I would have to show your quote to the electrician, because for my knowledge base (or lack there of), the logic is confounding. But after I show your paragraph to the electrician, he and I can discuss it. Thanks for that!!! Because I haven't a clue, I wonder if your – at the panel suggestion addresses the single ground discussion (I had above with AlMarg? ) and the difficulty addressing it in a situation where ganged outlets are several, have some distance between them and multiple dedicated circuits are involved? Quote Mrmb to AlMarg: “Speaking of electrical noise/hum, I just found a Martin Logan article speaking about pre-wiring https://www.martinlogan.com/learn/faq-prewiring-a-home-theater.php.).” “It addresses one of my other concerns about inserting multiple dedicated circuits in one room. They advise to connect all outlets/circuits with the same ground wire. I've previously read that ALL audio components should be connected together -- i.e., on the same dedicated circuit. If one didn't tie 2-dedicated circuits together by using the same ground, I can see why I've seen that advice.”
Quote Ottuso: Also why not use conduit? You could pull and replace wires to your heart’s content. Yes, when building, Conduit is your BFF!! One of the few things that I believe I have covered! Always consider Conduit NOT ONLY for future mains pulls, but also low voltage pulls. The mains concern -- rather than the need to later add a different gauge or romex configuration – in my mind, derives from the future transition to fiber. Speaking of same, I was surprised to recently learn that the fiber cable itself, was competitive, if not cheaper than copper. However, one must add-in the cost of the Fiber Media Converters (10/100, as well as Gigabit) that enable one to convert Ethernet network connection to a fiber network connection and vice versa.
Wow, perhaps light switches, but then I wonder if there any switches presently made with Ethernet connections so they can be inserted into the LAN? Perhaps so (I don’t know), in a professionally installed “smart” system? One, that as a DIY fan, I’m not interested in. Because I believe these professional installed systems are usually only installed and serviced by trained technicians – the only ones that are allowed to purchase and resell them. Being the cheapskate that I am, I would shy away from those. I know....I know, in some instances, and for some folks, the benefits outweigh the cost. Nevertheless, that’s why WiFi enabled light devices (and in some cases many different ones and manufacture’s are compatitable), are such good things for DIY’ers. Although granted, WiFi is not as robust as hard-wired. However, WiFi is changing the home automation game for DIY’ers in a really big way! Moreover, I’m not sure I want to, or need to live with “smart” appliances and thermostats. Personally, lighting and perhaps security systems are the only automation systems that I’m presently interested in. As always, and with everything else in life, that could change... Quote Hig3: “People above have already mentioned keep distance between 120v and low voltage wires. If they need to cross, 90 degrees is preferred.” Also as this thread has uncovered, each A/V critical Dedicated mains wire, needs to be handled in a similar fashion.
Interesting..... |
hig3: Also plan on at least one 20 amp circuit for your analog sources, and one for your digital sources. You should also have a separate circuit for your video components and displays. And one for your control system, if you will be using something like Control 4 or Crestron.After just deciding to install a 120" projection system adjacent to the 2-channel Soundlab room your suggestions help to decide how to managed the dedicated circuits. Having all |
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Mrmb/Mike: i wonder if an electrician would install 3 circuits with a common ground? With 2 circuits from vertically adjacent panel slots the hots would be out of phase - okay for a ground of the same wire gauge. 3 circuits would put 2 in phase. Perhaps, one could use 12 gauge for the hots and 8 for the neutral? Ask... Also why not use conduit? You could pull and replace wires to your heart’s content. |
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Buy this: Ideal, 61-164 SureTest Circuit Analyzer It will show you voltage drop. I installed a dedicated 20 amp circuit using a 10 wire with extra shielding. I also added a 2nd grounding rod. Your electrician won't likely have seen an analyzer like this one. Don't use cheap plugs and switches in your house. I used an AQ Energy plug, which is probably overkill, but it accommodated the 10 wire. For all other plugs, I pay about $5 each for the professional ones at Home Depot. These plugs have a strong grip. |
When dealing with large systems getting enough circuits is very important. Figure one 20 amp circuit, terminated in a duplex outlet per power amplifier or powered speaker. Hospital quality plugs also are worth the investment. A 20 amp circuit can handle most amplifiers up to 600 watts total power. Have the electrician run 10 gauge wire if you can afford it, and it is allowed by code. Also plan on at least one 20 amp circuit for your analog sources, and one for your digital sources. You should also have a separate circuit for your video components and displays. And one for your control system, if you will be using something like Control 4 or Crestron. The video and control circuits should be wired to one phase of the breaker box, and the audio components to the other phase. Power strips and "outlet bars" do a very good job of keeping the grounds on the same plain to help eliminate any ground loops that cause hum. You are planning on having three separate systems, so you will need a lay out for each system. Run at least 2 CAT 6 or 7 for control to each room, and two per video display. Shielded wire is always preferred for low voltage wires except speaker wires. If you have runs over 200 feet, consider fiber, it is very expensive, but worth it. If you plan on going to 4K video or 8K when it comes around in a few years, run wire with enough bandwidth now!!! 4K video will need at least a 10 gig network, and 8K is looking like it will need 50 gig. Wire is relatively cheap and easy to run when the walls are not covered yet. Also run a CAT 6 or 7 to each light switch, each of your appliances and your thermostat so you can wire them into your LAN. Computers, printers and phones should also be planned out. Wired is always preferred over wireless. You will probably need a LAN port for each component eventually when you figure out how many ports you want for your network switch. I will not even guess what you will need for your security system. People above have already mentioned keep distance between 120v and low voltage wires. If they need to cross, 90 degrees is preferred. |
@whart , LOL, This one? https://www.youtube.com/watch?v=s33ScN4D-HU How about this scene? https://www.youtube.com/watch?v=05WhNMT8FWE Jim |
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RACK & NETWORK COMPONENTS: Our LAN and COAX systems are as inelegant as they can get. But for a buck-ninty-eight vs $3,000, I will take the former any day. If I were doing it myself, which I physically can't, rather than $900 for a cabinet, I would nail shelves between the basement's 2x4's or install peg board to mount the components. Well probably not, but an open rack mounted between the studs, should work quite nicely and for 90% less $. The funny thing is this guy’s cable pulling labor was not outlandish and without crunching the numbers, significantly less than another Low Voltage guy’s quote, go figure. Lots of fun…. |
jea48 (Jim) Not all low voltage cable installers are created equal.A quote was obtained by whom our custom builder uses and I obtained one from a locally quite well reviewed (over 300 samples) installer. However he is sourcing cable from SnapAv were reluctant to tell him, but claimed to source Liberty CAT6. However, I wasn't too enamored with his insertion of a 23" $900 cabinet. Probably double its street price. Plus, he included labor to install the cabinet and its contents. Charge double for components and lob labor onto doing so -- good if you can get it! Yeah, I have ~36 CAT pulls. But Lutron and Tripp-Lite make an open rack for a fraction of the enclosed cabinet quoted. Bottom line: I'm still negotiating with the installer. I will keep your other comments and suggestions in mind. |
The biggest effect was isolation transformers. After installation, I compared different power cords as well as premium power conditioners on standard outlets, against the transformers, and nothing came close. But they do growl. Plitron makes a good one, and they sell direct to the public. The medical isolation transformers are best. I used braided shielding from a rack mounted central power supply on all my DC power cords as a default, so I cannot say with certainty, that they made much difference. I like to add what may be tiny incremental improvements where they can do no harm. Note that an amplifier is essentially a power supply modulator, so clean power is important. Fire protection was also on my list of benefits - the gas furnace is adjacent. And it's noise stays out too. By all means make it into adobe - let us know how it works out. |
mrmb said: Not all low voltage cable installers are created equal. Did you ask the electrical contractor who he uses? Make sure the Communication Company you hire will supply you with a copy of a certification test report for each data cable installed. Also the person testing the cabling, from the Patch Panel to wall jack, must be certified for the test equipment used. Here is some reading info. http://www.informit.com/articles/article.aspx?p=1403240&seqNum=3 Here, for an example, is a video showing an Ideal scanner cable tester. Go to time mark 7:50 to see what’s involved in testing a 4 pair Lan data cable. https://www.youtube.com/watch?v=wn-EsoD-FnQ What manufacture of cable CAT6 cable will be used? What manufacture of CAT6 Patch Panel/jacks and wall jacks? I like Panduit. A little more pricey than the competition. Pair twist is maintained right up to the terminations. Same jack plugs into their Patch panel plate. http://www1.panduit.com/en/products-and-services/products/safety-and-security/physical-network-secur... Jim |
Good unique suggestions terry9. They're accepted even before a contradiction. Was you experience a jaw dropping one when you first heard your system with "braided shielding for power lines"? Multi-function tweaks, what's not to like? Room resonance damping and fire protection all rolled into one (the 'ole sand on the fire trick). I wonder though, which color of sand works best for both purposes: brown, white, black, some combination, or with the additive of equal parts of snake oil and bull manure? |
I defer to both Almarg and Jea, so if either contradicts me, please accept that view. Consider an isolation transformer. I use one on every audio circuit, all of them grounded to to a common copper pipe, which is soldered to house ground (and paralleled to the oversized copper water line). But, isolation transformers do growl when they are doing their job, so it is important to site them outside the listening room. I also use braided shielding for power lines which are not metal clad, like DC power cords, especially near signal lines. As a result, my system is black. Also, you might want to consider sand in the walls. This makes the walls hard to move, because they are heavy, and to not ring because they are dead. There is more than a ton of sand in my ceiling. |
jea48 (Jim): Gesh -- forehead-slap -- reading one thing and assuming another, I apologize for my MC misinterpretation and confounding the issue!! You patience is appreciated! Although we've had 2 custom houses built previously, I seem to have spaced (as I did with the MC, NM-B issue) the hurry-up-to-wait process. When the builder told us that wiring should start soon, I thought jeez, although I had compiled lots of data, I didn't have a summary of same or conclusions to tell the electrician. You corrected that concern with your cogent and thoughtful replies. I will indeed use your advice when meeting with the electrician. Hopefully, it will go well, but Murphy's Law is ever-present. I'm dealing with the Low Voltage estimates presently. Fortunately I'm much more attuned to the ramifications of what was needed to be spec'ed. with CAT6, Q/S-RG6 and fiber. Especially how CAT6 should be kept separate from the Romax, much like you explained about with the minimum 12" separation of the individual parallell branch circuits. I'm sure that sort of spacing isn't something most electricians or low voltage technicans get overly concerned with, unless they're required to.... The "Mr. Blanding's Builds His Dream Home" with Cary Grant is indeed a classic. What a FUBAR position he found himself in. Sorta' like the beginning of "Green Acres" when Mr. Douglas (Eddie Albert) bought his farm house. Thanks for the grin with the mention of Mr. Blandings. Cary's movies are some of my favorites, as are his co-star's, Myrna Loy in the "Thin Man" series with William Powell. Humorous memories.... Thanks again, Mike. |
@mrmb , You might want to contact your builder and ask him if he would call the electrical contractor and schedule a meeting where you can meet with the contractor, or his representative, so you can address your concerns. The fact that you said the electrical contractor’s main business is commercial and industrial is a good thing. That does not mean the electricians that will be wiring your new house will be Inside Wiremen and not Residential Wiremen. (Pay grade is a lot less for a residential wiremen.) It’s not unusual for a contractor to employ both inside wiremen and residential wiremen. Not to mention residential wiremen are trained how to wire houses fast. Make sure at least one of the electrical contractor’s representatives you meet with is a State Licensed Master Electrician. He/she will have a better understanding of your concerns. Instructions will be given to the electricians who will be wiring your two audio/video rooms. It is a lot cheaper to layout the job on paper beforehand than to make changes after the job starts. Change orders can be/are expensive. If you have not watched the Cary Grant movie, " Mr. Blandings Builds His Dream House", I highly recommend you watch it. https://en.wikipedia.org/wiki/Mr._Blandings_Builds_His_Dream_House Jim |
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mrmb OP227 posts01-31-2018 9:47am @mrmb, I didn't recommend the use of MC cable over NM-B cable. I don't think Al, (almarg), did either. As I said in one of my posts I installed 10/2 with ground NM-B cable using plastic boxes for the two 120V 20 amp dedicated circuits for my 2 ch audio system. I believe you said your 2ch and HT rooms will be located in the basement. I assume at least one of the 200 electrical panels will be installed in a mechanical room in the basement as well. I assume from that panel, the 100 amp sub panel will be fed from. I assume the electrician will install the feeder wiring from the 200 amp panel, in the basement, to feed the sub panel through bored holes in the above engineered I floor joists, or trussed floored joists, above. The electrician, I assume, will also install the dedicated branch circuits wiring for the 2ch audio room and HT room from the sub panel. Either through the above floor joists or basement wall studs. Just make sure he keeps them from the ceiling can lights and load side branch circuit wiring of the can lights for reasons I stated in an above post. |
To Jea48, Jim: As previously noted above, Al deferred to your choice of Romex MC (Metal Clad) as opposed to his original choice of Romex NM-B, by saying that he had “no reason to doubt that”…MC..”was a better choice”. Well NOW, if you are BOTH suggesting MC -- winner, winner, chicken diner, that’s what I will definitely use! Because it is determined that I will DEFINITELY be installing MC (and NOT NM-B), then how does it get installed -- as compared to your excellent description below (beginning with your below quote labeled #1 -- of how to properly install NM-B? Jea48's, Jim's Quote: If you use NM-B cable for the audio/video dedicated branch circuits there are a few installation guidelines that should/must be followed. I assume the house will not have a basement or crawl space. You said in a post the branch circuits will be installed above the ceiling joists/rafters/attic space area.
I'm unsure how the basement question correlated to your following installation description. So, assuming that your NM-B comments apply ONLY to an “above the ceiling joists/rafters/attic space area”. Then for others reading this thread, and they’re going to use NM-B, what would your instructions for them be – i.e., what would you add or delete from the below 3 bullet points, for those that DO have a basement and want to use NM-B?
So, now that you provided those fine 3 bullet points for installing Romex NM-B, but I’ve decided, based on your recommendation and Al’s concurrence to install Romex MC, what are your recommended bullet points for handling and installing Romex MC? How do they differ from the above bullets? And a 2nd. question is: would you install MC ONLY for the dedicated CIRCUITS to be used for audio/video applications? Is NM-B (as opposed to MC) the Romex usually installed in a residential situation? Posed another way: is there a reason either from a handling, installation or quality of use perspective, why MC shouldn’t be installed house-wide, or why the electrician may not want to install MC house-wide? Again thanks for your assistance Jim! |
Very timely and prudent questions. I was on the AVS Forum yesterday searching for what folks were doing to their dedicated H/T rooms. All I saw pertained to SOUNDPROOFING -- i.e., stemming the sound between floors and rooms; which I really don't need. HOWEVER, I am very interested in suggestions about the ACOUSTIC applications that could be done to enhance the 2-channel experience and the H/T one, since both rooms are connected/adjoining -- i.e., tricks or tips that could be installed BEFORE the drywall is installed? In the past I've read about installing extra layers of drywall, using glue etc., but wondered if that had any advantage other than soundproofing. Please by all means let me know what would make sense to do.... While I was on AVS, I did find some good suggestions about isolating the projector from above the basement, main-floor vibrations; which was something I hadn't thought about -- a vibrating PJ is not a good thing, contrary to what she said (grin)! So, I was pleased to learn that. My area will be multi-functional. That is, the H/T side won't look like a theater. So, H/T equipment will be on a rack in front of the screen and speakers and subs won't be hidden etc. I like seeing my toys too much, ha! But I am considering installing can lights. Any sonic precautions to take with these? Also because I saw so many instances on AVS, I did briefly consider having bulkheads installed in our 9' basement ceiling, but other than for aesthetics, I couldn't imagine what the sonic benefits would be!? On the other hand, I do take acoustics and sound absorption VERY seriously and will do whatever it takes to tame the area, moderate standing waves and inhibit reflections!! But as I've done in our present house, that has been done after the drywall is installed. HOWEVER, if I'm missing something that COULD/SHOULD be done before the drywall, PLEASE let me know!! -Mike |
From the AA post above: almarg said:+1 ~ ~ ~ A 120V 12 amp load? What if the 12 amp load was fed from a single branch circuit? What then? 120V loads are changing all the time. Yes by code the electrician is supposed to balance the electrical panel connected 120V loads the best he can. But he doesn’t know what the home owner might plug into any given wall electrical outlet. How about a vacuum cleaner? Most draw 12 amps. Sure he can balance the circuits above the counter tops in the kitchen. He can put the circuit that feeds the microwave on a breaker fed from say L1 and the Dishwasher circuit on a breaker fed from L2. If they are running at the same time the two loads are somewhat balanced. What if the dishwasher is running and the microwave is not? Or the microwave is being used but not the dishwasher? Like I said 120V loads are changing all the time. The electrician tries to balance the 120V loads the best he can for the what if.... What you don’t do is move all the know 120V loads like the microwave, dishwasher, garbage disposal, washing machine, refrigerator, deep freeze, sump pump, and any other motor load you can think of to one Line, leg, in the electrical panel, so the other Line, leg, can be used for an audio system that draws maybe 8 to 10 amps tops. jea48 said:The sub panel 120V loads will be somewhat balanced. The same if the 2 ch audio room was fed with a single 120V 20 amp branch circuit connected to say L1 and the HT room was fed with another 120V 20 amp branch circuit fed from L2. What is the total connected load to L1? What is the total connected load to L2? What are the chances both systems will be in use at the same time? ~ ~ ~ @mrmb, Have you considered what you will be insulating the wall stud spaces with in the audio and HT rooms? Sound type insulation? What will you be covering the wall studs and ceiling joists with? Dry wall, sheetrock, I assume? How thick? How many layers? Type of glue used between layers? Resilient channels installed on wall studs and ceiling joists? Example of: http://www.soundproofing.org/infopages/channel.htm What ever you decide to do the electrician will need to know before he installs the outlet boxes. Type of lighting in the rooms. Jim |
Al, if you don't understand it, I'm not knowledgeable enough to speculate one way or the other. It would take about 3-minutes of typing to describe what I know about the electricity subject. Here goes: I can re-set a circuit breaker, screw-in a light bulb and on a good day, change out a switch or receptacle; but anything more, I'm flying blind. Hence, why this whole topic is such a mystery. I can't help but think that probably is the case for many. Which is exactly the reason why I believe a thread like this has such value to anyone in my position. Someone with virtually zero theoretical and practical knowledge about power distribution. Which is what makes you and Jim's commentary so valued! I inserted the AA post because I thought it may help someone in a similar circumstance. Hopefully, our electrician will know how best to balance the load and not install something that would be over sized, or present an "asymmetric load" -- as the A/A poster said. |
Wow, this is great information.+1. Great info indeed. Thanks, Jim! Mike, I don't understand the AA post you quoted. In the stated example it seems to me that if the load is unbalanced by 12 amps, it is unbalanced by 12 amps regardless of whether the sub-panel is a 60 amp panel or a 100 amp panel. Best regards, -- Al |
Did not see it mentioned, you want to make sure you buy main and sub panel that have copper buss bar, Square D QO , Siemens, cutler hammer. I ran a Sub panel like you want to I used 0 THNN which was way oversize for a 100 sub, glad I did. You may want to also consider whole house surge protection, wires right into your main panel. One last thought, a lot of folks on dedicated lines, incorporate Isolation transformers. Congrats on your new home! |
Wow Jim, GREAT response!! Ask and ye shall receive. Thanks so much for your recommendations. It sure helps me provide specific instructions to the electrician; whether I fully understand the technical logic behind the instructions or not. Wiring should begin in ~2 weeks. Contrary to your assumption which would normally be correct, the electric company sub-contractor does have a significant commercial and industrial resume, in fact, it's greater than it's residential one. The good news is that our builder doesn't skimp on labor or materials. The bad news is we're paying for that (grin). So, (2)-200 amp panels plus (1)-100 amp sub-panel were included in the estimate. The question for my electrician is whether the sub-panel should be 60-amp or 100-amp. From the following A/A thread, it appears that too much "headroom" (i.e. 100 vs 60 amps etc.) could be a problem: My builder has already greased the skids with the electrician by telling him I would have some pretty unique needs. In turn, via email, I sent the electrician a heads-up of some of my general needs, including links to my gear. Next because of your help, I will document the specifics of what we're desiring and place notes for him on the pdf's of our house plans. I really appreciate your comments about the breaker box wiring!!! That was one area that had me stumped. Especially because the sub-panel will be dedicated to JUST A/V type equipment. I suppose installing a sub-panel is prudent. The box is fairly inexpensive and it will be placed closer to the 2-channel audio alcove and the adjacent entertainment/home theater area. These areas are combined in a "L" type configuration. Only extend the bottom leg of the "L" to look like the traditional perpendicular drawing. The audio room is at 1-end of that leg and a bar is at the other end; with the H/T room on the other end of the "L". Fearing as you suggested, that the bare minimum would be provided, I was happy to read your suggestion of feeding "the sub-panel with at least #4 copper or #2 aluminum wire". Speaking of same, do you find any value in doing the connection as I found someone advised on another forum by: “running one large wire from the very top position in the load center on the leg with the least number of noise-generating devices to a sub-panel”?Lastly, if it means anything relative to your service grounding commentary, we're in Indiana. All the best, -Mike |
@mrmb , Where to start. Electrical code says the safety equipment grounding conductor shall be part of, installed in, the cable with the current carrying branch circuit conductors. I guess the electrician could tie all the equipment ground wires together with a bonding jumper at all the wall rough-in outlet boxes locations. You would need to ask him if he has a problem with it or if the AHJ, (Authority Having Jurisdiction), Electrical Inspector would have a problem with it. I am pretty sure, depending on the State and city you live in, the electrician will install AFCI (Arc Fault Circuit Interrupter) breakers in the the load center panel that will feed the new dedicated branch circuits. Connecting all the equipment grounds together at outlet boxes could cause a problem. I don’t know, the electrician might know. I personally do not see the need to bond all the equipment grounding conductors together at the wall outlet boxes, IF, the proper branch circuit wiring is used and the proper branch circuit wiring installation method is followed for audio/video branch circuit wiring. Just a guess the electricians that will be wiring your new home are Residential Wiremen. They will follow, meet, the bare minimum electrical safety code required by NEC and the AHJ in your area. That is how the electrical contractor bids the job. You will need to spec and pay extra for any additional materials and wiring methods you want for the audio/video branch circuit wiring. Your wants must meet bare minimum electrical safety code standards for your area. You can exceed bare minimum electrical code standards all you want. It’s what ever you can afford. My suggestions are based on NEC, (National Electrical Code), standards. The AHJ in your State and or local governing body has the final say. The main electrical service. Depending where you live, soil resistivity and severity of lightning storms, the earth connection of the electrical service is very important for lightning protection. In my area I highly doubt any residential electrical contractor checks the electrical service grounding electrode to earth resistance. They just supplement the required ground rod with a second ground rod. That meets the requirement of NEC. IEEE recommends 5 ohms or less. NEC says if the grounding electrode to earth resistance is greater than 25 ohms it shall be augmented by one additional ground rod. That’s it, no further testing is required. https://en.wikipedia.org/wiki/Soil_resistivity The test must be preformed by someone that has been trained and certified for use of the testing equipment used. I would suggest you hire a well established "Power Quality" testing company in your area. Most large Commercial/Industrial Electrical Contractors can recommend one to you. Price in my area runs around $150 to $200 for the testing. IF additional earth grounding is needed to achieve a ground rod to earth resistance of less than than 5 ohms you will have to pay an electrical contractor to install the additional earth grounding electrodes. Usually more 10ft earth driven ground rods is not the answer. In most cases a 30ft deep driven ground rod will do the job. (Three 5/8" X 10ft ground rods coupled together.) BUT it depends on the soil resistivity where you live. I think I pretty much covered the rest of your questions in my last post. I will add if you are going to install a sub panel feed it with at least #4 copper or #2 aluminum wire. For audio equipment, system, connected together with wire interconnects it is recommended the dedicated branch circuits be fed from breakers fed from the same Line, Leg. All from Line 1 or all from Line 2, not from both though. In your case, If I read you posts correct, you have multiple A/V systems. You could balance the sub panel out by using line 1 for one system, connected together by wire interconnects, and the other system, connected together by interconnects, from Line 2. If the electrician questions your directions, for feeding the dedicated circuits for each system from the same Line, just tell him the total connected continuous load is less than 16 amps. And the dedicated circuits are intended to be used to feed audio and video equipment only. That should satisfy him as well as the electrical inspector. Speaking of the electrical inspector, there is a very good chance the electrical code in your area requires "Tamper Resistant" receptacles. Are your audio grade duplex receptacles Tamper Resistant? The electrician will have to install Tamper Resistant outlets for the final electrical inspection otherwise the inspector will Red Flag the job. Not to mention the inspector will chew out the electrician for installing non Tamper Resistant ones, wasting his time on a callback inspection. I am not going to suggest what you can do after the final inspection an the occupancy permit has been issued. Dedicated branch circuit wire size for the 2 channel audio equipment? I would install overkill and use #10awg solid copper wire. The breakers will be 20 amp making them 20 amp circuits. For the speakers I would install #12awg solid copper wire minimum, fed from a 20 amp branch circuit breaker. Type of branch circuit wiring used? If you choose NM-B use plastic boxes, not ferrous steel boxes. The electrician will use deep plastic boxes for the #10 solid wire. He will need all the room he can get for the #10 solid wire to make up on the duplex receptacle outlet. Ask the electrician to please connect the #10 solid wire to the side terminal screws, by curling the wire clockwise around under the screw head, instead of using the back wire terminal screw plate to secure the wire. The connection made under the screw head will remain tight even as the electrician pushes, forces, the duplex into the wall box to complete the installation. What are you using for a duplex cover plate? Avoid low grade stainless steel plates with ferrous materials. It will degrade the sound. Use a strong magnet to check for ferrous materials in the cover plate. A cheap nylon unbreakable/flexible plate works just fine. If you use MC cable make sure the electrician buys solid copper conductors and aluminum armor. Yes it can be bought with stranded wire conductors. The electrician would much rather work with stranded #10 wire instead of solid. Problem with using MC cable is the type of wall rough-in boxes used. I am not a fan of steel ferrous boxes used for the duplex receptacle outlet. For what it’s worth I installed two 20 amp dedicated circuits, using #10/2 with ground MN-B sheathed cable, that are around 75ft each in length from the electrical panel to the wall outlets for my two channel audio system. The system is dead quiet. Jim |
Jim said: I assume the house will not have a basement or crawl space. You said in a post the branch circuits will be installed above the ceiling joists/rafters/attic space area.The house does have a walk-out basement. In fact, that is where 2 of the 3 audio/video rooms will be, with the most important one being my 2-channel Soundlab room. |
And the cable is? It looks like Jim prefers what he linked to: Solid copper 10/2 with ground MC aluminum armor cable. https://www.homedepot.com/p/Southwire-10-2-x-125-ft-Solid-CU-MC-Metal-Clad-Armorlite-Cable-69117005/... Have I got it? Both the clad and un-clad seem to be the same price, so cost isn't an issue. If indeed I got it right and clad (MC) is the choice, would that only be for the A/V areas that I want dedicated lines to, in the new house? My total guess is that it would seem that unclad -- NM-B -- may be easier to work with for all the other pulls. So, that means that MC will be used for my audio dedicated lines and NM-B will be used everywhere else? |
@mrmb, I am still working on a reply to your long posted message. You asked a lot of different questions. In response to your last post. Thanks Jim: To make sure I got it, the lower GVI of MC aluminum clad a negative and thus, supports Al’s suggestion of using NM-B?No it’s a positive thing. The lower the GVI the better. With that said I would say the majority of dedicated branch circuits installed for audio equipment is NM-B cable using plastic rough-in wall outlet boxes though. If you use NM-B cable for the audio/video dedicated branch circuits there are a few installation guidelines that should/must be followed. I assume the house will not have a basement or crawl space. You said in a post the branch circuits will be installed above the ceiling joists/rafters/attic space area. 1) * Each NM-B cable needs to be installed separated by at least 12" from any other parallel run branch circuit wiring. More than 12" is better yet. If the parallel ran dedicated branch circuit cables are not kept separated from one another, as well as other parallel branch circuit wiring, the magnetic fields of the AC current carrying conductors can/will induce a voltage onto the equipment grounding conductors of the other cables. This can cause ground loop hum problems. The induced voltage can/will also transfer AC noise (EMI/RFI) from one cable to the other. Dedicated branch circuit NM-B cables must be kept separated from one another as soon as reasonably practicable after existing the electrical panel all the way to the drops down the wall stud cavity to the wall rough-in boxes. That includes keeping the dedicated circuits rough-in wall boxes separated from one another by at least 12" or more. * * * EDIT: Depending on the location of the sub panel to the room, the dedicated branch circuits will be installed, it is possible the electrician could install the dedicated circuits entirely through individually separated bored holes in the wall studs. 2) * MN-B cables should be installed at least 5ft from any ceiling lights / can lights where dimmers, or LED, or CFL lighting is used. That includes load side branch circuit wiring of the noisy harmonic producing items. The nasty, filthy, harmonics will infect the audio dedicated branch circuits if the electrician does not keep the audio dedicated branch circuits away. https://www.youtube.com/watch?v=OCK5W9vlAE0 3) * Same goes for the sub panel feeder that will feed the sub panel. I assume the electrician will install a 3 wire + ground NM-B cable to feed the sub panel from one of the 200 amp electrical panels. Keep the feeder away from harmonic producing things like dimmers, LED and or CFL light fixtures. That includes load branch circuit wiring. I’m still confused at to whether we should use NM-B vs. XHHW vs. THHN.The insulated conductors used in NM-B sheath cable is THHN insulation. http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet6 XHHW? Single insulated conductors pulled/installed in an empty conduit after the conduit is installed? Are you thinking of having conduit installed? Any experience with XHHW vs NM-B when used for audio? My guess is that it would be difficult at best, to try to discern a sonic difference between the two (I hate auditioning audio cables; let alone Romex). So why not just USE what’s readily available (NM-B)? Sound like a plan? XHHW is commonly used in industrial facilities where its’ add heat temperature rating is desired. Because of the tough insulation XHHW also has a high resistance to chafing due to vibration inside conduits, boxes, make up boxes for large motors, and such, where vibration may be a factor. XHHW insulation is tough as steel nails. XHHW is also used in underground conduit runs for its’ added moisture/water protection properties. It will hold up better in hash environments far better than than THHN/THWN will. Beats me how it would have any impact on the SQ of audio equipment though. Here is a pro audio white paper for you to read through. https://www.anixter.com/content/dam/Images/Logos/Supplier-Logos/Middle-Atlantic/PowerPaper.pdf Jim |
Thanks Jim: To make sure I got it, the lower GVI of MC aluminum clad a negative and thus, supports Al's suggestion of using NM-B? I'm still confused at to whether we should use NM-B vs. XHHW vs. THHN. One of the differences of XHHW verses the other 2 is in the insulation. XHHW's is Polyethylene; whereas NM-B and THHN is PVC. One poster in another forum suggested that Polyethylene Insulation (& thus XHHW) may be better. However, a quick search suggests that NM-B is the most prevalent and thus, should be what we recommend to our electrician -- i.e. Southwire Brand Romex NM-B. Any experience with XHHW vs NM-B when used for audio? My guess is that it would be difficult at best, to try to discern a sonic difference between the two (I hate auditioning audio cables; let alone Romex). So why not just USE what's readily available (NM-B)? Sound like a plan? |
