New Electrical Circuit
I have an older house with open circuits so I am wiring a new dedicated circuit for my audio gear. Before I do so, would it be very advantageous to bump up the quality of the outlet and / or wiring to improve quality or is this overkill? Has anyone done this in the past and what would you recommend?
@puffbojie said:
That is correct. .
No, for the reason you stated in the above quote. .
Usually stated as minimum. Does not imply maximum of 15 amp circuit. (YMMV with your amp.) Food for thought. Why are the majority of consumer power amplifiers sold in the US designed to be plugged into a 120V 15 amp wall outlet circuit? Because the majority of wall outlets circuits found in the home are 120V 15 amp convenience outlet circuits with 15 amp duplex receptacle outlets. .
No... When looking at aftermarket power cords for power amplifiers seldom is a 20 amp (5-20P) 20 amp plug installed on the power cord. To require a 5-20P 20 amp plug the amplifier would have to have a continuous FLA rating of over 12 amps, not more than 16 amps. In most cases a 5-15P, 15 amp plug is used. What size wire, equivalent wire size, is used for the audiophile power cord? Might be #12 rated for 20 amp. might be bigger than #12awg. 10awg is common, 30 amp rating. Equivalent, #9awg and sometimes even bigger. Well that make no sense... Especially if the in wall branch circuit is a 15 amp circuit. My guess the electrician that told you a 15 amp circuit is all you need is going to use 14 gauge wire. 14awg is rated for 15 amps. (How long will the branch circuit wiring be? Distance from electrical panel to wall outlet?) Now nothing prohibits the electrician from installing #12awg or even #10awg branch circuit wiring and connecting it to a 15 amp circuit breaker in the panel. The circuit is still a 15 amp circuit. The breaker handle rating determines the size of the circuit. Not the size of the branch circuit wiring. Why bigger conductors, awg wire? AC mains Line VD, (Voltage Drop) under load conditions. Not just continuous load but for audio amplifiers high dynamic quick peak draws of current caused by the musical source material being played. Example: .
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Does AC mains VD impact the sound of a power amplifier? From my listening experience it does. YMMV. FYI, a 15 amp circuit breaker will pass quick short draws of current well above its’ 15 amp handle rating all day long without tripping open. The breaker doesn’t see or care about VD on the wiring. FYI if you have a 15 amp branch circuit installed, per NEC code you cannot install a 5-20R 20 amp duplex outlet on the 15 amp circuit. I believe that most of the audiophile outlets sold today are 5-20R 20 amp outlets. NEC code does allow 2 or more 5-15R 15 amp outlets on a 20 amp branch circuit. A duplex receptacle is two. . |
@jea48 Regarding the 20 amp circuit, vs a 15 amp circuit, would you not need a 20 amp plug on the amp’s power cord for the unit to utilize the 20 amps? -and what if the amplifier only calls for 15? Would there still be a benefit? My understanding is when connecting the amplifier to a 20-amp circuit that the amplifier will draw only the current it requires. I guess the question I am getting at is: should I use a 20 amp power cord/ “plug” for the amp to match up with my 20 amp circuit? |
OP I ran a years long test using a bunch of high end receptacles, and came out with a few winners: Furutech GTX-D(G gold) or GTX-D(R rhodium) depending on your tastes, Oyaide R-1 which has platinum and palladium coating)......these stood out amongst all others I tried. I am installing one each of these on 3 dedicated lines in my new listening room If anyone is on a budget, the Acme Audio Labs at $60 are excellent....and great replacements for stock receptacles without breading the bank. Silver plated over higher copper content brass |
Not a simple question to answer. Best answer I can give is, It depends. How long are the home runs? How many branch circuits will be installed? (You mentioned 3) Cost of a good sub panel and feeder to feed the panel ain't cheap. As for where the sub panel will be installed. I read occasionally where the panel is installed in close proximity to the wall outlets being fed. By close I mean less than 25ft of wire. Jmho that defeats one of the reasons for installing multiple dedicated branch circuits. To decouple audio equipment AC power supplies from one another. Not much impedance and inductance in 15 to 25ft length of wiring. . |
Not really. The electrician can use a, (example), EMT to AC/MC/FMC/NM Transition Fitting . He will remove the aluminum armor for the length of the EMT conduit and the wire needed for make up in the electrical panel. Or he can use a junction box inside to transition from EMT conduit box connector to an MC cable box connector. I think the EMT to MC transition fitting would work better, jmho. Your electrician on the job site will know what will work best for him for his install situation. If you decide to have MC cable installed make sure the electrician installs 3/8" anti-short bushings on all cut MC armor ends. Anti-short bushings are not required by NEC code. Have him install them anyway... They protect the insulation on the conductors from the sharp edge of the armor. . |
@jea48 My electrical box is outside. Can they encase the (Southwire Armorlite 125-ft 10/2 Solid Aluminum MC (Metal Clad) Cable) inside metal conduit for the outside portion for weather proofing? |
For a residential house I never recommend an isolated ground. It would not serve any purpose what so ever. FYI even in commercial and industrial facilities an IG, Isolated grounding conductor and IG type outlet are seldom used now days. They where big in the 1970s, 80s and 90s. They started fading in the early 2000s. I recommend 2 wire solid copper aluminum armor MC cable. Example: 10/2 Solid copper Aluminum armor MC (Metal Clad) Cable The reason I like MC cable better than Romex is because of the way it is constructed. Hot, neutral, and insulated green equipment grounding conductors are tightly twisted together in a spiral twist and held tightly together by the armor. MC cable NOT AC cable (commonly called BX). AC cable is garbage for feeding audio equipment. Romex is ok provided care is taken when installing it. Avoid twisting the cable as not to change, distort, the lay of the EGC (Equipment Grounding Conductor) between the Hot and neutral current carrying conductors. That’s next to impossible to do. If you tell the electrician to install the Romex keeping the cable flat without any twists. He will think you are nuts... Read pages 12 and 13. Note the chart on page 13. Integrating Electronic Equipment and Power . |
@jea48 Do you normally specify isolated ground and is that why you recommend MC? |
My guess, the electrician you are hiring is not an audiophile. He is basing his install of a 15 amp branch circuit on bare minimum electrical code. Electrical code could care less how an audio system sounds. Is it electrically safe? Code is satisfied. Like others have said have a 20 amp branch circuit installed. Slight difference in cost for the wire. Breaker and labor cost no difference. It’s a no brainer imo. Bare minimum for a 20 amp circuit is #12awg copper. You can have larger wiring installed if you choose. If the length of the branch circuit wiring is 50ft or longer from the electrical panel to the wall outlet I would recommend #10awg solid wiring. Breaker in electrical panel will be 20 amp. I would also recommend a minimum of two dedicated 20 amp branch circuits One for digital sources and SMPS 120V power supplies, the other for analog 120V power supplies. Reason, it helps decouple the digital 120Vac power supply(s) from analog 120Vac power supply(s). A dedicated branch circuit... A circuit with a dedicated Hot, Neutral, and EGC (Equipment Grounding Conductor). A true dedicated branch circuit should never be installed in a common conduit or cable assembly with other branch circuits. Current carrying conductors can/do induce voltage from one branch circuit to the other(s). (See Overview of Audio System Grounding & Interfacing Link below.) If two or more branch circuits are installed for audio or audio video equipment that is connected together by wire interconnects the branch circuits should be fed from circuit breakers on the same Line, leg, in the electrical panel. 2 conductor NM sheathed cable (Romex) is widely used by audiophiles. I used to recommend it to feed audio equipment. I now recommend 10-2 solid copper MC (Metal Clad) aluminum armor cable. I consider myself a qualified audiophile Licensed Master Electrician. Reading material: Read pages 11 through 13. Integrating Electronic Equipment and Power Read page 16. Read pages 31 through 36. Overview of Audio System Grounding & Interfacing Jim . |
I am with you with respect to managing noise in the mains supply. But I think most of the electrical noise affecting our components is generated by other components in our own audio chains. In particular, I have a subwoofer with a class D internal amplifier which injects so much noise into the power cable feeding it, that it completely destroys digital TV reception. The fix was ludicrously cheap - just a couple of ferrites round the power cable. This is an extreme example, but is completely reproducible. |
You did not say what country you are in! Most of the answers assume USA, but in much of the rest of the world we use higher voltages, so much less current is drawn for the same power. My supply is nominally 240-V RMS, though it is usually 250. Outlets are rated for 10-Amps, with 15-Amps for bigger loads like running a caravan! Someone mentioned phases, in the context of stages of rewiring. In Alternating Current (AC) mains electrical supply, there are usually three phases using three wires running down a street. Each phase is an AC sinewave rotated 120-degrees from its neighbours. Often, each house just gets one phase. When the lights are out in every third house, you know one phase has gone down! For high power devices (like my sauna and big bench sander) we have the option of using all three phases (3 wires plus earth) for three times the power. The average power delivered through three phases is very smooth - none of the stops and starts and reverses you get with single phase AC. Oddly, I have never come across audiophile power supplies designed for 3-phase. Another difference is that we use 50-Hz, not 60! |
I ran a dedicated 20 amp circuit. Leviton 8300-R 20-Amp hospital grade outlet. ZeroSurge 8R20W power conditioner. Preffair Audiophile HiFi shielded power cord, 10AWG, rhodium plated. Made no difference whatsoever. Skin effect, jitter, and drift do not make an audible difference. Circuits that handle audio are all powered by DC, so the correctness of the AC sine wave makes little difference unless it is massively out of whack. |
One standard receptacle has two outlets. If you need 4 or 6 outlets you’ll be using, respectively, 2 or 3 receptacles. You’re using the same receptacle "unit" regardless of how many outlets. Multiple receptacles in one box should be bussed rather than daisy-chained. Receptacles should always be wired at their screw terminals, NEVER backstabbed (although for some unfathomable reason backstabbing is still Code-compliant in the US). Enjoy!
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I’ve done several rooms over the years when we moved households. This latest was in an 1880’s Texas Gothic (Victorian) which had a full restoration in 2004. Almost the entire first floor, (with the exception of the kitchen) was original, including all woodwork, transom windows, shutters, etc. The listening room, upstairs is modern, and loft-like. I had a couple of phases of electrical work done. First, I had a commercial electrician go over the entire electrical system starting at the meter- which the power company pulled to inspect the meter block. A feed was run to a sub panel and since I had planned to install a large iso transformer, the feed continued upstairs- all done in 4 gauge. That led to a service panel for the music room- copper buss bar--and 10 gauge dedicated lines. System sounded a little bright for a couple weeks- wired with a junction box where the iso transformer was to be located (it was built to order). When it was installed, I cannot say it made a dramatic difference in sound, but the system was dead quiet. I use 104db efficient horns and you can hear grounding anomalies among components, and any noise on the line. Even though I am very close to downtown, the system is far quieter than it was in NY, along the Hudson, where the infrastructure was old. Next phase was installing a whole house generator. I wanted to avoid the problem Fremer complained about- that the automatic transfer switch, which is filled with semiconductors- made his system sound terrible. I figured there was a Code compliant way to wire the system so that it was powered from the service entrance before the ATS/Generator. I called on Rex, who helped Fremer re-do his system. Rex can do this remotely with drawings over the phone for modest cost. The electrician installed an ATS with its own breaker box--and only those appliances that are wired directly to the ATS breakers are supported by the generator. The hi-fi stayed on the main service panel, thus not connected to the ATS. I probably eliminated 1/2 the breakers on the main panel, everything got checked and tightened. The system sounds better than ever. I attribute that to fewer breakers on the main panel and having everything tightened; put in a fresh grounding block (I think they are zinc) that ties main ground to other utilities like phone and cable-I have neither, but do have Google Fiber here). I like to use commercial electricians b/c they are used to dealing with big equipment, heavier loads, etc. The grounds all tie back to the main household ground- a Ufer which is essentially rebar in the concrete foundation. Think carefully about receptacle layout for future needs, especially if you are breaking drywall to install the power lines. It’s a little messy-- I had this done before the system was uncrated and installed. Everything got patched and painted first. You don’t have to go to the lengths I did-- FWIW, I use the last of the Porter Ports Albert had. I did have a copper ground bar installed near the front end of the system (also tied to the household ground) in case I needed a verified "ground" for some additional equipment. The digital side (modest) runs off the regular household wiring- there is a power conditioner on that circuit, but not on the main system or analog side. There is a surge board in the iso transformer and I bought a new whole house surge- the Siemens (yikes the price on that doubled in the last couple years), but all good. Most electricians are not audiophiles- sometimes you’ll find a commercial electrician that has done work in stadiums or other venues. Those guys are used to the demands audiophile place on their work. Get several quotes and find an electrician that does both commercial and residential. That’s where I’ve gotten my best results. Good luck. @Jea48, a member here, is very knowledgeable on NEC but Code can vary (more requirements than national) based on location. The National Code is a minimum standard. Overkill is not a bad thing. |
Good article from MSB website: https://msbtechnology.com/faq/house-power/ |
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@fuzztone 14 is thinner than 12. I think you meant 10. FWIW I have two 20a dedicated circuits with 12awg romex. |
@puffbojie I am an electrician, so I installed them myself. # 12 AWG RW90 wire, 20 amp Sqaure D QO breakers for my panel, and Cardas Plugs. The difference was well worth the effort. Dead quiet, larger soundstage, seemed deeper and wider, the presence felt bigger. |
I'd run 20 Amps, which immediately requires 12 gauge wiring. At a bare minimum, use Commercial/Residential outlets, which now have to be Tamper Resistant (TR). Relatively affordable ($4-5 each). While your electricians are in there might as well also put in a whole house surge protector in the panel. |
@hilroy48 The electricians have it scheduled for 15 amp circuit. So a 20 amp is the way to go? What about the size or type of wiring ? |
Cruze first audio, Maestro outlets. These are like a component upgrade. I'd used Porter Ports for years and figured they were ok. Maestros don't change the sound of your system. You just get more of everything. Type in "outlets" in the search bar, you'll get all you want to know about all the different brands. Cheers |
