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I'm having an electrician install an upgraded circuit panel and a dedicated line for my audio system. The panel will be about 35-40' from where the 20 amp outlet will be.
My question is what gauge wire should I have him put in? I've heard 12AWG should work, but was told by someone else I should use 10AWG for this distance.
Which would be the correct gauge to use? Thanks.
Follow Ups:
Taking your distance, max voltage drop at max load, and other parameters into consideration, 12AWG will work more than perfectly fine and your voltage drop will be minimal even if you were to draw a continuous 20-Amperes.... which you will never do.
Using the proper gauge in your case will not be skimping at all. 12AWG is MORE THAN adequate. But of course, audiophools like to spend MORE THAN NECESSARY (sometimes much more) on just about everything. We're all guilty of that! It's just a matter of where you want to foolishly spend your money! ;-)
I had a 20-Amp dedicated circuit installed for my audio setup a few years ago. It was a ~40-Foot run from the breaker panel to my audio gear. I have no issues and no regrets going with 12AWG, and I've had a couple large hot running tube monoblocks in the system.
You are correct about this! And I bet all the amps listed have a 15 amp ac fuse not 20!
Be prepared to pay more for labour as 10g is a bear to work with.
1. Consult with your electrician about this.
2. As long as you are going to the expense of doing this, do not
install only one duplex outlet. Install at least 2 and perhaps 3 duplex
outlets. If possible, put each duplex outlet on its own breaker.
nt
Thanks to all for you replies.
I purchased a cryo Hubbell HBL 5362 from Cabledyne.
Ed, the owner did suggest a deep metal box, not plastic, but to use plastic for the conduit.
Quote is for the NEC 2008 edition, same for the latest 2011 edition
Quote from Link provided.
NEC Article 90 draws boundaries around the National Electrical Code—boundaries many people fail to understand. For example, Article 90 has long made it clear the NEC is not intended as design specification or instruction manual. The National Electrical Code has one purpose only.
NEC 90.1 has four subdivisions:
(A) says the purpose of the NEC is the practical safeguarding of people and property "from hazards arising from the use of electricity."
(B) distinguishes from the adequacy concept (provisions necessary for safety) and other concepts. The Code is a minimum standard. Further effort may be required for an installation to be efficient, convenient, or adequate for good service or future expansion. This is a fundamental concept upon which many Code disagreements arise. The Code is not a target you’d like to hit. It is the minimum you can do.
(C) clearly states the Code is not intended to be a design specification or instruction manual.
You will have a voltage drop of .47 volts
if you use #12 wire instead of #10 wire.
Jerry P
Bob24,
jea48 makes two very good points -
1: #12 wire is the minimum
2: getting away from an Aluminum bus
The incremental cost is well spent.
When I re-wired for dedicated outlets, I used #10 for approximately the same distance and have been quite satisfied with the effects.
Happy contractoring
40 feet is not a long run. A 20 amp circuit can handle 2400 watts. An audio system would never come close to using that kind of power. Anything more would be something you would never use. This is not a hot tub we are talking about! You can do what you want but IMHO you would be wasting your money!
What is the equivalent wire gauge of the conductors in the cord/s? How long is it?
Yes the conductor size of the OEM cord that came with the audio equipment is more than adequate. Who says so? The manufacture says so.
The cord and plug meets all minimum safety standards of UL and or CSA or what ever other recognized testing Lab Listed standards.
An audio system would never come close to using that kind of power...
of course you're using high powered amps from companies like Audio Research, Emotiva, Pass Labs and VTL - among others. In some cases, the mono amplifiers each require a 20A circuit.
While the total current draw of the upstairs system is about 17.5 A, I use two dedicated 20A circuits to provide better isolation.
Unless...
Absolutely correct!
Not really correct. Those amps idle at 300 watts each and the absolute most they will ever draw is 1000 watts each, and if they ever got there, both at the same time, it will be a momentary peak power consumption of 2000 watts. That will never happen.
So even under the absolute worse case scenario he would have been just fine with a single 20-Amp circuit run.
To which do you refer? I listed brands, not models. Ok, let's fix that.
Check out the requirements for the Emotiva XPR, Audio Research REF750, VTL Siegfried, Pass Labs X1000.5, etc.
Has categorically stated that the 20 amp circuit "requirement" for the XPR Series of amps is only there to satisfy bench testing requirements which in no way mimic real-world use. There are many XPR users running their amps on 15 amp circuits with absolutely no problems.
-RW-
the power rating of the XPR-5 is overstated. It is rated at 600 watts x 5 at 4 ohms. While Class H isn't 100% efficient, let's assume it is for the moment. That's a 25 A draw.
While that's peak, why would anyone purchase an amplifier and hook it up to a circuit that cannot meet its current requirements?
"The XPR-5 requires a 20 Amp circuit and...
While that's peak, why would anyone purchase an amplifier and hook it up to a circuit that cannot meet its current requirements?
In the majority of homes in the US, living rooms, dens, family rooms, bed rooms, are wired with 15 amp branch circuits using #14 ga wire. Therefore the receptacles in those rooms are 15 amp duplex. If a manufacture wants to sell his/her products they better make sure it will have a 15 amp plug on the end of the cord.
With that said NEMA says if manufacture uses a 15 amp plug to feed his equipment the FLA cannot exceed 12 amps. That does not mean the equipment cannot draw short quick bursts of power well over 12 amp.A standard 15 amp breaker will pass quick surges, bursts, spikes, current fluctuations of over 100 amps. Of course the power amp in question won't draw bursts of current as high as a 100 amps but the point is it should handle what the amp throws at it.
It would be interesting to see what the voltage at the receptacle is doing if the user is listening to music with lots of dynamics at a fairly loud level on a 15 amp circuit that is wired with #14 awg wire for the amplifier in question. E x I = P
I personally don’t want my audio system to sound fine. I strive for it to sound great.
Edits: 11/16/13 11/16/13
If a manufacture wants to sell his/her products they better make sure it will have a 15 amp plug on the end of the cord.
That being the case, they failed in this instance. The entirety of my quoted text reads:
"The XPR-5 requires a 20 Amp circuit and standard IEC 20 Amp outlet (which is different than a 15 Amp outlet)."
But,
Big Dan, owner of Emotiva...
Posted by rlw (A) on November 16, 2013 at 04:46:11
In Reply to: "Those amps?" posted by E-Stat on November 15, 2013 at 09:50:39:
Has categorically stated that the 20 amp circuit "requirement" for the XPR Series of amps is only there to satisfy bench testing requirements which in no way mimic real-world use. There are many XPR users running their amps on 15 amp circuits with absolutely no problems.
-RW-
Curious? Does the manufacture of the amp supply the power cord with the amp? I am guessing not. Is the IEC power inlet on the amp a 20 amp?
For some strange reason you can buy a Listed power cord that has a NEMA 5-15P amp plug on one end and a 20 amp IEC connector on the other end. Makes no sense to me.
Try buying a Listed cord with a NEMA 5-15P 15 amp plug on one end with a 5-20R receptacle on the other end. You can't.
Does the manufacture of the amp supply the power cord with the amp? I am guessing not.I'm guessing they do. Follow the pictures link found on the first post of this thread
Looks like a 20A plug to me.
edit:
For some strange reason you can buy a Listed power cord that has a NEMA 5-15P amp plug on one end and a 20 amp IEC connector on the other end. Makes no sense to me.
Audio Research among others uses this approach even with line stages. Why? The connector is said to be more secure and less subject to movement than a lesser IEC.
Edits: 11/16/13 11/16/13
Yes, and I see so is the IEC inlet on the back of the unit a 20 amp.Power specs......
Power Requirements: 115 VAC or 230 VAC +/- 10% @ 50 / 60 Hz (user selectable).
The XPR-5 requires a 20 Amp circuit and standard IEC 20 Amp outlet (which is different than a 15 Amp outlet).If you don’t have a proper circuit and outlet, we recommend you have one installed by a qualified electrician.We recommend that the XPR-5 be plugged into its own dedicated 20 Amp circuit.
I see the amp is CE certified. I would assume the certification is given using the 20 amp rated power cord.
I personally would not plug the amp into a 15 amp circuit.
Note the max AC power consumption by the IEC inlet. 3500 watts.
3500/120V = 29.17 amps. 3500/115V = 30.43 amps. Wonder how big the line fuse is inside the amp?
Power Supply:
3.3 kVA toroidal power transformer.
180,000 uF of storage capacitance
WOW what a pig!Going from memory, the ampacity rating of wire shown in NEC Article 300 Table 310-15(B)(16) is actually for the termination point of the wire at the breaker and receptacle in general simplified terms. UL says for #2 and smaller wire the 60 degree C column shall be used. Hopefully if cdb reads my comments here he will chime in.
I would like see what the wire and insulation looks like at the receptacle and receptacles that might be wired daisy chained on a 15 amp circuit fed with #14 ga wire when this amp has been connected to it for a few years. I would bet the copper wire is discolored from heat and the insulation if not burned back from the termination point will be hard and brittle.
Edits: 11/16/13 11/16/13 11/16/13
"I see the amp is CE certified..."
CE is a "self-certifying" label. Yes, I agree to follow your guidlines/specs/RPs/whatever. No lab, no testing/inspecting of random samples, AFAIK. Not an OSHA approved NRTL (see linky).
"NEC Article 300 Table 310-15(B)(16)"
It's Art 310, Table 310-16 and above for for conductor ampacities.
Emotiva seems confused and the bosses' comments don't help matters. I may have missed it, but I didn't see any power draw numbers in their spec column. ARC also has me confused. It seems all their Reference line of products now have a 20A IEC, regardless of power draw. A dealer told me it was for parts standardization (weak), a tighter connection (possible & probable), and they sound better on a 20A circuit (everything? partial bunk).
In my dream world, and with Powerball winnings, I'd get Neutrik to make a line voltage/amp rated XLR connector for power connections. A mini pin-and-sleeve connector if you will...
"UL says for #2 and smaller wire the 60 degree C column shall be used." Correct, though the text is actually 100A , over and under. #2AWG being the 60C 100A cutoff point where you jump to the 75C column.
This is from ULs "green book", Electrical Construction Materials Directory , Appliance and Utilization Equipment Termination section. Any guidelines in that book are NEC mandatory per NEC 110-3(B).
I've avoided this wire size discussion since the OP omitted one critical fact, and that's the load served size. Length of circuit run is fine, but without a load in amperes, it's (IMO) all guesswork.
Personally, I'd do additional 20A/#12AWG circuits rather than try and bulk up a single one with fence-wire-stiff #10AWG. Unless the residence is a monster McMansion with runs over say,125ft,(just to grab a fast number) and a monster HT setup, I wouldn't see Vd as much of an issue, for small-to-moderate sized 2CH systems. If so, at some rapid point a local sub-panel would be called for.
Sometimes forgotten is the fact that stereo equipment has a specified operating voltage spread. It's not going to sound bad because you have 119VAC at the outlet, nor better if you have 121VAC.
CE is a "self-certifying" label. Yes, I agree to follow your guidlines/specs/RPs/whatever. No lab, no testing/inspecting of random samples, AFAIK. Not an OSHA approved NRTL (see linky).
In other words worthless.... The amp would never pass UL or CSA, jmho.Emotiva seems confused and the bosses' comments don't help matters. I may have missed it, but I didn't see any power draw numbers in their spec column.
Just the 3500 watt by the IEC male connector on the back of the unit.
And this,
Power Supply:
3.3 kVA toroidal power transformer.
180,000 uF of storage capacitance.
Sure would like to know the size of the equipment Line protection fuse.NEC Article 300 Table 310-15(B)(16)"
It's Art 310, Table 310-16 and above for conductor ampacities.
Sorry about that, don't know why I typed Article 300 and not 310. Especially when I got the Article, 310, correct in the Table.
For the 2011 NEC edition Table 310-16 is now Table 310.15(B)(16).
Page 70-154. A lot of code changes in the 2011 edition.
Personally, I'd do additional 20A/#12AWG circuits rather than try and bulk up a single one with fence-wire-stiff #10AWG.
I would tend to agree if he was installing at least a couple 20 amp circuits. Total connected load? Who knows.Curious if the OP added into his length calc, up out of the panel and down to the recept location. Also if routing will affect the total length. You would be surprised how many newbie electrical estimators figure feeders lengths short. They forget to add the up and down, over and around.
Unless the residence is a monster McMansion with runs over say,125ft,(just to grab a fast number) and a monster HT setup, I wouldn't see Vd as much of an issue, for small-to-moderate sized 2CH systems. If so, at some rapid point a local sub-panel would be called for.
Well depends. Sometimes there is not a space for a sub panel. You have to consider resale. Some people don't care for the looks of a flush panel cover in a habitable room.And then I remember reading places you do not want multiple dedicated branch circuits too short if your intension is to decouple the power supplies of audio equipment from one another. (Digital from analog)
My audio room's 2 dedicated circuits for the 2 channel system are over 75' from the panel. Both circuits are
#10-2 W/Grd NM-B cable. Preamp (tube), power amp (tube), and phono preamp SS, on one circuit, digital on the other. System is dead quiet.Sometimes forgotten is the fact that stereo equipment has a specified operating voltage spread. It's not going to sound bad because you have 119VAC at the outlet, nor better if you have 121VAC.
Probably true if the voltage changes are somewhat steady state. But what if the changes in voltages are fluctuating fairly rapidly due to dynamic music played at a moderate to loud level. What does that do to the power supply of the amp and the power supplies of other equipment that is fed off the same circuit?
Edits: 11/16/13 11/16/13 11/16/13 11/20/13
"But what if the changes in voltages are fluctuating fairly rapidly due to dynamic music played at a moderate to loud level. What does that do to the power supply of the amp and the power supplies of other equipment that is fed off the same circuit?"
A well designed power supply should effectively isolate the downstream circuits it powers from rapid line voltage fluctuations AND it should also largely isolate the line from rapid fluctuations in downstream energy draw. This is part of the benefit of a large power supply energy storage capability in the form of "charged" power supply capacitors and/or inductors when there is no active power supply regulation employed. If long term and slow fluctuations are important, active regulation should be employed.
And then there's the variability in voltage supplied to your main panel that's caused by random load switching by your neighbors who happen to be on the same distribution transformer as you. No dedicated circuit will reduce or correct this condition.
Overall, I believe it's very easy to lapse into marginally effective AC power overkill once basic safety and convenience issues are addressed.
A well designed power supply should effectively isolate the downstream circuits it powers from rapid line voltage fluctuations AND it should also largely isolate the line from rapid fluctuations in downstream energy draw. This is part of the benefit of a large power supply energy storage capability in the form of "charged" power supply capacitors and/or inductors when there is no active power supply regulation employed. If long term and slow fluctuations are important, active regulation should be employed.
Agree. A well designed power supply ...... How about a not so well designed power supply? Not all power supplies are created equal.
And then there's the variability in voltage supplied to your main panel that's caused by random load switching by your neighbors who happen to be on the same distribution transformer as you. No dedicated circuit will reduce or correct this condition.
Highly unlikely a home owner would experience voltage fluctuations on his mains caused by varying loads of a neighbor home owner sharing the same utility transformer.
"Highly unlikely a home owner would experience voltage fluctuations on his mains caused by varying loads of a neighbor home owner sharing the same utility transformer."
Happens frequently at my location, esp during a summer heat wave when central AC is in full force. Momentary blips to around 110V when compressors start and long term sags to 115V when nominal is ~121V. I can also tell when my neighbor is using his welder.
Happens frequently at my location, esp during a summer heat wave when central AC is in full force. Momentary blips to around 110V when compressors start and long term sags to 115V when nominal is ~121V. I can also tell when my neighbor is using his welder.
Summer air conditioning loads not only put a demand on the transformer feeding your home and your neighbors A/C units on the same xfmr, but all the other A/C units on utility xfmrs. All those loads put on the HV Line that feeds the xfmrs to the sub station all the way back to the generating plant.I would bet most of the short, blips, voltage drops you are experiencing is from your own A/C unit kicking on.
I can also tell when my neighbor is using his welder.
That you do not have to put up with. Call your power provider. Ask them nicely if they would have someone come out to your home to investigate the situation.Solution may be to increase the size of their xfmr.
If the neighbor is running a business out of his garage and the area you live in is not zoned for the type of business, the Power Company MAY have the right to disconnect power from his premisses if he does not stop using the arc welder.
Or they may contact or instruct you to contact the local zoning dept in your area.
A simple phone call can't hurt.
Edits: 11/17/13
Emotiva seems confused and the bosses' comments don't help matters.
Remember that you are relying upon the unsupported claims of one individual. I withhold judgement until I see factual information.
...a tighter connection (possible & probable)
No $hit. Isn't that what I said?
In Reply to: Other points posted by cdb on November 16, 2013 at 15:11:39:
Emotiva seems confused and the bosses' comments don't help matters.
Remember that you are relying upon the unsupported claims of one individual. I withhold judgement until I see factual information.
Good point!
It was in a post about a similar Sherbourn 7-350:
Dan's comment
That notwithstanding, the manual has a different take than the Prezdent:
" We STRONGLY recommend that the PA 7-350 be attached to a dedicated power circuit. Under real-world conditions, with typical loads, playing music, the PA 7-350 will deliver full dynamic power when attached to a single dedicated 115 VAC 20 A circuit! If the PA 7-350 is to be used for demanding commercial applications or under laboratory conditions, a dedicated 230 VAC 30 A circuit is REQUIRED.
Why bother buying a high powered amp if you plan to starve it for current? Maybe that makes sense to someone.
Power specs...
I linked to the Emotiva page several posts back.
180,000 uF of storage capacitance
WOW what a pig!
It uses ON MOSFET outputs, so the rails are likely not run higher than 60V. Assuming that's the case, it has 320 odd joules of storage.
Even my 300 watt VTL MB-450 mono amps have 250 joules each. The Audio Research REF750 mono amp , by contrast, has 1300 joules!
I was referencing your VTL MB-450's (per your profile) if that is what you are still running. How do you arrive at 17.5 Amps of current draw? It doesn't add up when I do the math, and certainly not a continuous 17.5-Amps.
Do you know if the OP runs Emotiva XPR, Audio Research REF750, VTL Siegfried, or Pass Labs X1000.5?
If so, you put in two runs of 12AWG using two circuits, not 10AWG or fatter on a single circuit.
Unless your gear draws more than an electric dryer, I would bet that 12AWG is more than adequate for 99.99% of all home audiophile setups.
Maybe he's in the that last 0.01%, but I seriously doubt it. ;-)
I was referencing your VTL MB-450's (per your profile) if that is what you are still running.
In the main system, yes.
How do you arrive at 17.5 Amps of current draw?
Left MB-450 1000 watts/8.3 amps
Right MB-450 1000 watts/8.3 amps
SP-9/DAC-7/Touch/Scout/U-1s ~ 100 watts/.83 amps
Do you know if the OP runs Emotiva XPR, Audio Research REF750, VTL Siegfried, or Pass Labs X1000.5?
Have no idea. For context, read my original response to BCR where he avers that "An audio system would never come close to using that kind of power."
Many do.
If so, you put in two runs of 12AWG using two circuits, not 10AWG or fatter on a single circuit.
Correct. Electrician wanted a couple hundred more for the longish runs. Spent the money towards Skyline diffusers instead.
One amp and preamp connect to one circuit with outlet to left of dormer. The other amp and turntable run to other circuit with outlet on right side. DAC/Touch linear PS connect to a third, 15 A line behind rack.
How do you arrive at 17.5 Amps of current draw?
Left MB-450 1000 watts/8.3 amps
Right MB-450 1000 watts/8.3 amps
SP-9/DAC-7/Touch/Scout/U-1s ~ 100 watts/.83 amps
You will never draw 8.3 amps of continuous current from either of those amps alone, and even less likely to have both drawing that kind of current simultaneously in order to arrive at 17.5 Amps total.
That is, however, what the system can draw. You could say that manufacturers really don't need to supply power cords that can handle the potential current draw either. But they do.
Automobile manufacturers don't have to supply tires that have speed ratings that match the vehicle's capability. But they do. Did BMW just put some P rated ties on your 1 series?
For the past five years, I've taken the vintage system next door for Halloween parties the neighbor hosts for his teenaged daughter. The source material has always been compressed content and this year, was streamed from Soundcloud. For four hours, the Stasis runs wide open - likely with some clipping - with the LED ladders always at the top. The speakers used are double New Advents. One year, the surrounds on one pair were reduced to shreds. I suspect it was drawing near its potential draw for an extended period of time. :)
...or for a screeching tornado warning siren! Most audiophiles don't use their systems that way.
But back to the point.... The OP doesn't need 10 AWG wire for his dedicated circuit. To suggest that he might regret not installing it, is misleading. Even your system at a supposed (but doubtful) 17.5 Amps continuous draw doesn't need 10-AWG wiring.
If you're going to draw that kind of current, near 20-Amps or more continuous, you run two sets of 12-AWG on separate circuits. That's all.
If you like 10-AWG that's fine but it's not even close to being necessary, Holmes. ;-)
The OP doesn't need 10 AWG wire for his dedicated circuit.
Agreed - for the same reasons I chose 12 gauge for my runs.
If you're going to draw that kind of current, near 20-Amps or more continuous, you run two sets of 12-AWG on separate circuits. That's all.
Which is exactly what I did! We most certainly agree. :)
Well then why are we putting so much effort into agreeing? ;-)
Seriously, have a nice weekend. I'm getting out of here for a while since the weather is still nice outside.
I was listening to the garage system since it was 80 degrees out !
I'm having an electrician install an upgraded circuit panel
What brand, manufacture and style?
I personally would not install a panel that has aluminum bus.
Go with copper.
A good panel is a Square D QO Load center. Copper bus with copper breaker connecting bus ties.
Square D Homeline is a cheap residential grade panel that uses aluminum bus where the breaker connection bus ties are aluminum. (One piece bus and breaker connecting tie)
GE,ITE, residential grade also use aluminum bus.
Edits: 11/15/13
For a 20 amp branch circuit #12 is bare minimum wire size per code.
.....Bare minimum.....I would install #10 solid core wire, especially if you are only installing one dedicated branch circuit.
Install the #10, then later you won't say "what if" or "I wish I had."Note:
The branch circuit breaker size will still be 20 amp. The branch circuit will still be a 20 amp branch circuit.The electrician will try to talk you out of it though. #10 solid can be a bitch to work with compared to #12, as well as make-up in the receptacle rough-in box. Tell him to use a deep box.
Edits: 11/13/13
sufficient, but 10 gauge may be preferable. You're not talking a lot of wire here.
For the 20A dedicated runs I'm putting in for my new second floor demo room, I'm using all 10 gauge solid core, twisted. Overkill to be sure even though the run is perhaps twice as long as yours, but why cut corners.
Brian
When I had two 20 amp lines run, the electrician told me 12 gauge fully met code. When I asked about 10 gauge, he said that supports 30 amp lines if you should need it.
I have 12 in my runs.
And hardly anybody around here carries 10 gauge solid core.
Do you put premium gas in your car? Does it require it, or does it just run more smoothly and perhaps have a bit more pickup?
My runs will be maybe 60 feet or so. Yeah, it might be seen as a little looney, but so what.
Brian
> > Do you put premium gas in your car? Does it require it, or does it just run more smoothly and perhaps have a bit more pickup? < <
Premium gas does not provide "a bit more pickup" to an engine designed to run on 87 octane. In fact, it can actually reduce performance and cause more carbon buildup. Higher octane gas is harder to combust, and this is so that high compression engines do not suffer from pre-iginition (pinging, knocking, pre-detonation).
Lower octane gas actually combusts more easily and fully in a lower compression engine, thus giving you more power. If your engine is not running 10:1 or higher compression, there is absolutely NO need to use high octane gas. In fact, doing so is foolish...
-RW-
Do you put premium gas in your car?
Yes, but all of them have been tuned for it. I use regular for engines tuned for that grade.
If you want to use 10 gauge, then take advantage of code and put in 30 amp breakers.
If you want to use 10 gauge, then take advantage of code and put in 30 amp breakers.
Sorry can't do that if you are planning on using standard NEMA 5-15R or 5-20R duplex receptacles. The maximum breaker size is 20 amp.
.
...that the NEC addresses primarily safety, both personal hazard and fire. The code gauges are "safe" for the ampacity specified but may or may not be adequate as regards other factors such as voltage drop under load. This is where the professional comes into play. Also, the 30A circuit recommendation comes with added baggage: special 30a rated outlets are required. Since these outlets don't accept the standard 15 or 20A plugs found on most equipment and appliances available in the US, a true code rated 30A circuit in a domestic setting would be inconvenient at best and hazardous at worst.
30A outlets are not REQUIRED on 30A branch circuits.
(Nor are 20A outlets required on 20A branch circuits.)
30A outlets are only needed for 30A LOADS.
The breakers are sized to protect the branch wire from overheating.
The breakers don't care what is plugged in to the circuit.
NEC Table 210.21(B)(3)
30A receptacle on a 30A circuit.
(Ignoring arc welder and fractional horsepower exceptions...)
A single 20A receptacle is required on a 20A circuit. NEC 210.21(B)(1).
One or more duplex receptacles may be 15 or 20A rated on a 20A circuit. NEC 210.21(B)(3).
...your understanding of code reqmts is not my understanding. Don't have the book in front of me so I can't cite chapter and verse but I believe there are considerations beyond simple branch circuit protection. Practically, a standard 15 or 20A outlet on 30A branch circuit would allow an appliance with an 18GA SPT type cord to be attached to it. It's my understanding that #18 cord may fail catastrophically when subjected to the instantaneous fault current that a 30A breaker might pass before opening the circuit.
But hey, I'm not a code expert so that's why I'd be consulting a pro if my needs went beyond the commonplace. In the spirit of education, if you can point me to the portion of the code that permits (or doesn't prohibit) what you state it does, I'll learn something and so may a few others around here.
30A outlets are not REQUIRED on 30A branch circuits.
(Nor are 20A outlets required on 20A branch circuits.)
30A outlets are only needed for 30A LOADS.
Sorry, that is not true.
A 30 amp receptacle can only be installed on a 30 amp branch circuit.
A 20 amp receptacle can only be installed on a 20 amp branch circuit.
Two or more 15 amp receptacles, a Duplex, can be installed on a 20 amp branch circuit.
This does not negate what I said.
If you use a 30A receptacle, it must be used on a thirty amp branch.
If you use a 20A receptacle, it must be used on a twenty amp branch.
You can use a smaller rated receptacle, i.e., 15A, on a 20A branch. The breaker is rated to protect the house wire, NOT what is plugged into the receptacle. 20A plugs can accept a 15A plug, which may be attached to a load with 16# wire or less.
If there is a requirement that only a 30A receptacle is allowed with a 30A breaker, which would require a minimum 10# wire, then I stand corrected.
However, getting back to the original poster, 10# wire, which is rated for 30A, can be used with a 20A breaker. You don't HAVE to use a 30A, and it is also not needed for a *normal* home hifi load. The purpose of going 10# is not for more current capacity, but to lower voltage variations under varying load.
If there is a requirement that only a 30A receptacle is allowed with a 30A breaker, which would require a minimum 10# wire, then I stand corrected.
Yes there is.
NEC Table 210.21(B)(3)
Circuit rating 30 amps, Receptacle rating 30 ampsYou can use a smaller rated receptacle, i.e., 15A, on a 20A branch.
Yes two or more. NEC 210.21(B)(3) and Table 210.21(B)(3)
The OP is buying a 15 amp 5262 duplex receptacle and it will be installed on a 20 amp branch circuit. That meets NEC code.
NEC 210.21(B)(1)(3) Table 210.21(B)(3)The breaker is rated to protect the house wire, NOT what is plugged into the receptacle. 20A plugs can accept a 15A plug, which may be attached to a load with 16# wire or less.
True but what if some non-qualified person installed a 20 amp receptacle on a 15 amp branch circuit? That is against code. Why? When a manufacture designs and builds a piece of equipment he is supposed to follow NEMA standards for the cord and plug he will use to power the equipment. Note the word supposed.... If he is a reputable manufacture the equipment will be Listed by some recognized safety testing Lab like UL or CSA. In that case NEMA standards shall be followed.If the FLA of the equipment is 12 amps or less the manufacture can use a NEMA 15 amp plug.
If the equipment FLA is over 12 but less than 16 amps then he will use a NEMA 20 amp plug.
NEC Table 210.21(B)(2) Max Cord-and-Plug Connected Load to receptacle.So the non-qualified person installed a 20 amp receptacle on a 15 amp branch circuit. For sake of argument the recept was installed near a window. The person moves that lives in the residence and a new person moves in. He decides to supplement the cooling in the room with a window air conditioner. The plug on the end of the cord is a NEMA 20 amp plug. He plugs the plug into the 20 amp recept, no problem.
Let’s say the FLA on unit is 14 or 15 amps. Problems?
However, getting back to the original poster, 10# wire, which is rated for 30A, can be used with a 20A breaker. You don't HAVE to use a 30A, and it is also not needed for a *normal* home hifi load. The purpose of going 10# is not for more current capacity, but to lower voltage variations under varying load.
Agree! Especially in this case where the OP is only going to install one dedicated 20 amp branch circuit. We have no idea what audio equipment he has or what he may buy in the future. But if he has a big power amp and likes to play his music loud the rest of his equipment will appreciate he installed the bigger wire when he plays his music loud and the dynamic fluctuating current draw of the primary winding of the power transformer on the AC dedicated circuit will hopefully keep the voltage constant and not fluctuate keeping in beat with the music, LOL.
Edits: 11/15/13 11/15/13 11/15/13
Might want to throw an edit on this post:
http://www.audioasylum.com/audio/general/messages/66/662567.html
Make that Square D panel a "QO" instead of "OQ". (:> )
nt.
...special 30a rated outlets are required. Since these outlets don't accept the standard 15 or 20A plugs found on most equipment and appliances available in the US
Thanks. The electrician didn't do into that detail when we discussed wire gauge.
I find that a pair of dedicated 20A circuits provides a surfeit of adequacy for the upstairs system. :)
That's the difference between engineering and building. I heard some fellow in Home Depot the other week telling his buddy how the house he was building was going to be with 2 x 12" floor joists on 12" centers, so it would be "built solid".
Totally unnecessary, both in the cost for the material and the expense to install it, to say nothing of additional weight to support. It may seem like a good idea, but if it isn't needed then it's just additional cost for no good reason.
I heard some fellow in Home Depot the other week telling his buddy how the house he was building was going to be with 2 x 12" floor joists on 12" centers, so it would be "built solid".
My new upstairs demo room has 14" deep floor trusses at 12" on centers. The floor hardly moves at all when you jump up and down, to the point of feeling like concrete. Is that nuts? Maybe. The cost saving of going to 16" on center was minimal. Then again, the architect didn't account for the fact there's a load bearing wall about halfway along the span, so deflection is reduced to almost nothing. But consider there will be a system costing several hundred K in the room.
"Brick outhouse" comes to mind.
Brian
Architects and engineers are pretty good at specifying a floor that won't collapse, but I haven't found too many of either that have a friggin' clue about deflection.
That said? Trusses, TJIs, LVLs, and other such things are way in my past.
Curious who supplied your trusses Brian? If your project had been 5 or 6 years ago, I probably would have been bidding on the job (if you looked at all the local suppliers.)
The floor and roof trusses came from some supplier in Ohio, ordered through Menards by the builder.
Brian
12 gauge is fine!
Thanks for your advice.Much appreciated!
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