There are calculations for lighting load, continuous versus non-continuous loads etc. The one receptacle per circuit was a specific case: a 15A receptacle on a 20A circuit. There are separate rules for fixed appliances, welders, etc. If a single receptacle is rated for the load the breaker can supply, there is never a concern. Sorry if I misled you. There's also the 80% load/125% supply rule (same thing, just backwards math). This is also different depending on the type of load involved. Now that that's clear as mud...
Things to specify to an electrician for dedicated circuits?
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There are calculations for lighting load, continuous versus non-continuous loads etc. The one receptacle per circuit was a specific case: a 15A receptacle on a 20A circuit. There are separate rules for fixed appliances, welders, etc. If a single receptacle is rated for the load the breaker can supply, there is never a concern. Sorry if I misled you. There's also the 80% load/125% supply rule (same thing, just backwards math). This is also different depending on the type of load involved. Now that that's clear as mud...
BTW the building I work in has all 20 amp circuits with no more than six 15 amp receptacles on each outlet circuits.ByteWrangler
Active Member
My understanding is that if there is a single receptacle on a 20 Amp circuit then it must be a 20-Amp recept. One duplex receptacle is two receptacles, so the issue is moot in that case.
I have not seen a maximum number of receptacles on general-purpose branch circuits specified in the 2005 NEC (I could have easily missed this, but six seems unduly low). Our local codes (amended from NEC 2002) allow no more than ten receptacle outlets per branch circuit. The 2005 NEC defines an outlet as "a point on the wiring system where current is taken to supply utilization equipment", receptacle as "... a contact device installed at the outlet for the connection of an attachment plug. A single receptacle is a single contact device with no other contact device on the same yoke. A multiple receptacle is two or more contact devices on the same yoke." and receptacle outlet as "an outlet where one or more receptacles are installed", so the restriction on the actual number of receptacles is essentially unlimited (within the limits of practicality) if I understand correctly.
If you're putting in a dedicated circuit for, say, a laundry in a residence (which is required by NEC in most cases), it must be a 20-A circuit, per 2005 NEC 210.11(C)(2), and must have no other outlets other than for washing machine(s); according to NEC 210.21(B)(1) "A single receptacle on a branch circuit shall have an ampere rating not less than that of the branch circuit.". Therefore, if you use a singleton on a 20A circuit, it must be rated for 20A. Using a 15A duplex receptacle is apparently OK because a duplex receptacle is two receptacles (even though only one washer - if there's only one - is supposed to be plugged into that circuit).
Just for aggravation, the installation instructions for the new front-loading washing machine we just bought a few days ago says "ELECTRICAL REQUIREMENTS - CIRCUIT - Individual, properly polarized and grounded 15 amp. branch circuit fused with 15 amp. time delay fuse or circuit breaker." Emphasis mine - note the period after "breaker"; not "15 amp. or greater". Would they deny a warranty claim because it's on the 20-A circuit required by NEC? Cute. IMO, NEC trumps Whirlpool; if they are that concerned, they should put a 15-A slo-blo fuse or CB in their appliance.
I'm thinking about pulling a "homeowner's permit" for a fairly involved electric upgrade in my basement, so I've been reading up on this stuff. I did a lot of wiring with my dad on our property (he had been a licensed electrician before getting a PhD and teaching Physics), and working for an electric contractor summers 35 to 40 years ago, which is how I managed to buy a McIntosh stereo while in college. The basics are still the same, but there sure are a lot more details now! Let me tell you, the recent National Electric Code gives the US Tax Code a real challenge for convoluted rules!
Forgive me for getting windy and pedantic. I'm trying to have a good grounding (so to speak) on this stuff before approaching the city for a permit. This is good practice.
The NEC is a horribly written document, IMHO. They somehow make it even worse with each revision. It almost as if they purposely (dis)organize it to cause confusion. I actually have a book on codeology (that's its actual title) from my apprenticeship. Then there's the ultimate disclaimer: its only the minimum requirements. The authority having jurisdiction (inspector) has the final say as to whats acceptable. If you're pulling your own permit I'd assume you'll have to pass inspection. I strongly suggest talking with the inspector before you start your upgrade. Then you'll both be on the same page as to exactly what he/she wants. Reworking a rework can be expensive, time consuming and frustrating. BTW, I recommend only Square D QO (NOT homeline). Steer clear of anything else. You'll also need to know which code revision to use as most municipalities are usually enforcing old revs, some are still using 1999. Talking with the inspector can save you lots of headaches.
ByteWrangler
Active Member
Excellent advice, MudPuppy. I'm still not sure I'm going to go through with this, but even if I don't I've learned a lot. One thing I've learned (and you obviously already know well) is that the NEC is poorly organized and extremely difficult to understand. But I'm stubborn, and do refer to other books to help untangle things.
According to its website, which is usually up to date, the city is still using NEC 2002 with some amendments (recepts & lights must be on different branch circuits, no more than 10 receptacle outlets per branch, no more than 9 light fixtures per branch, smallest allowable wire is 12 AWG copper). I don't mind the added restrictions and will be going well beyond the minima dictated by local code anyway.
Consulting with the inspector first is a great idea, but i want to have my ducks in a row as best I can before doing that. I figure that if it looks like I know what I'm doing before talking to him (her), everything will be easier.
Unfortunately we already have three GE panels in the house and garage that all use the same breakers, so I'd prefer to keep the same style; some circuits will move from the main panel to a basement subpanel. Dad always preferred Square D; he always used the best stuff he could get for his own place. I do know that GE is better than Zinsco. Ugh!
According to its website, which is usually up to date, the city is still using NEC 2002 with some amendments (recepts & lights must be on different branch circuits, no more than 10 receptacle outlets per branch, no more than 9 light fixtures per branch, smallest allowable wire is 12 AWG copper). I don't mind the added restrictions and will be going well beyond the minima dictated by local code anyway.
Consulting with the inspector first is a great idea, but i want to have my ducks in a row as best I can before doing that. I figure that if it looks like I know what I'm doing before talking to him (her), everything will be easier.
Unfortunately we already have three GE panels in the house and garage that all use the same breakers, so I'd prefer to keep the same style; some circuits will move from the main panel to a basement subpanel. Dad always preferred Square D; he always used the best stuff he could get for his own place. I do know that GE is better than Zinsco. Ugh!
The code is actually divided into three sections: design, build and use. I don't remember the sections of demarcation but that's the "thought" behind it. GE stands for good enough and the only thing they make that doesn't suck is their vacuum cleaners we always say! One "oddball" QO panel wouldn't hurt any more than your first piece of quality audio gear. Of course then you'd want more.....
Why? I've read this a few times on these forums. The power comes from the same phase with the center grounded (neutral). There is no difference between the halves of the same phase. You have single phase power. Yes, multiple houses share the same transformer. Their loads vary as yours so there will be minor voltage "variances" between legs. What is the advantage of more load (amps) on one leg and less load (sources) on the other? Shunyata (and others) appear to be furthering their snake oil sales with more snake oil tales. Isolated power supplies are one thing, this is another.
Gregory
Soundco Kid
We're having noise (grit) problems!! It turns out the the Mc system is on the same `wall socket´ circuit as the computers are, i.e. the office, and we usually have two PCs and two big 21" monitors on most of the time. Recently changed out one CRT for a LCD screen. What kind of noise were you having?
-Gregory
Gregory
Soundco Kid
I personally believe using #10 in this case is getting a bit carried away. 30A circuits are for appliances that draw continuous current where conductor heating is involved. Some examples are machinery like compressors, saws, and welders, even space heaters. Have a look at the following as a guide:
15A - 14 AWG - 1800 watts
20A - 12 AWG - 2400 watts
30A - 10 AWG - 2600 watts
Audio is not continuous sine wave power either!
-Gregory
beerdraft
Active Member
Mudpuppy176, it seems you are or at one time have been an electrician. It also seems you are knowledgeable about all electrical things. I don't pretend to try and understand things when an expert gives me advice which I didn't have to pay for. The snake oil reference is not needed, IMO, shunyata made nothing off of giving me these specs, they already had my business with the conditioners and power cords. In respect to an electrician not understanding these spec's, I talked to 4 electricians and only one understood the use of 10 gauge and he also knew about amps and sources being on same and different legs. I didn't ask for an explanation. This guy did a lot of wiring for sound stuff and already used that theory,AGAIN "THEORY"... I think, think being the key word, that the spec's all come back to trying to deliver the best signal with the least noise and less chance of a ground loop, As I said I didn't have to understand it I just did the specs the way I was told. It didn't cost me any more money to do it this way and I needed all 3 circuits.
misterdoggy1
Well-Known Member
Guys
As we speak I am having an electrician install this beast below. It is a precision voltage regulator made by TSI. Its a 230V 20AMP which is the equivalent of a 110V 40AMP voltage regulator.
It will go right next to the main fusebox and make a direct dedicated line to the HIFI line of plugs.
It will keep the current and voltage stable within a miniscule range 3% no matter how the input changes.
The Current in my area was damaging equipment and I had no choice. Cost me $1600 and its a solid serious unit, not like the flimsy Furman Regulators which work by "taps" this thing is built. 50lbs solid.
Great Stuff heres their website and some fotos of my rig
http://www.tsipower.com/Automatic-voltage-regulator-precision-ac.htm#VRp
http://audiokarma.org/forums/attachment.php?attachmentid=88750&stc=1&d=1209064385
http://audiokarma.org/forums/attachment.php?attachmentid=88751&stc=1&d=1209064385
As we speak I am having an electrician install this beast below. It is a precision voltage regulator made by TSI. Its a 230V 20AMP which is the equivalent of a 110V 40AMP voltage regulator.
It will go right next to the main fusebox and make a direct dedicated line to the HIFI line of plugs.
It will keep the current and voltage stable within a miniscule range 3% no matter how the input changes.
The Current in my area was damaging equipment and I had no choice. Cost me $1600 and its a solid serious unit, not like the flimsy Furman Regulators which work by "taps" this thing is built. 50lbs solid.
Great Stuff heres their website and some fotos of my rig
http://www.tsipower.com/Automatic-voltage-regulator-precision-ac.htm#VRp
http://audiokarma.org/forums/attachment.php?attachmentid=88750&stc=1&d=1209064385
http://audiokarma.org/forums/attachment.php?attachmentid=88751&stc=1&d=1209064385
Attachments
I am indeed an electrician. One out of 4 understood the use of 10AWG? These were certainly not properly trained electricians. Whatever method you used to locate them is obviously faulty. I have yet to hear any logical reason for amps and sources to be on different legs. I surmise you suggested that to him and he obliged to make the customer happy (and right). Smart man. You'd probably not hesitate to call him again and/or refer him some more business. I'm not saying it hurts to put them on different legs, but I fail to see a benefit.
nsgarch
McStatic
A couple of things (I think) I didn't see mentioned:
1.) Make sure all your dedicated circuit breakers are on the same side of the neutral buss bar in the panel box. You might even have to move an existing breaker to the other side to allow this.
2.) Use 10AWG over 20feet, but not less than 12AWG. It's not that hard to work with these sizes if you are using receptacles with "gas-tight" connectors (which you should be.) These connectors clamp down on the wire, you don't wrap the wire around a screw!
1.) Make sure all your dedicated circuit breakers are on the same side of the neutral buss bar in the panel box. You might even have to move an existing breaker to the other side to allow this.
2.) Use 10AWG over 20feet, but not less than 12AWG. It's not that hard to work with these sizes if you are using receptacles with "gas-tight" connectors (which you should be.) These connectors clamp down on the wire, you don't wrap the wire around a screw!
beerdraft
Active Member
Code:
[QUOTE][quote="MudPuppy176, post: 1812786"] I have yet to hear any logical reason for amps and sources to be on different legs. I surmise you suggested that to him and he obliged to make the customer happy (and right). Smart man. You'd probably not hesitate to call him again and/or refer him some more business. I'm not saying it hurts to put them on different legs, but I fail to see a benefit.[/QUOTE][/QUOTE]I wouldn't call the guy who knew this stuff again because he didn't get the job. They didn't have to understand my specs to do them, just run them the way I specified. The electrician doesn't have to be brilliant to run lines, if he did we'd have a lot fewer electricians to choose from. Don't know the reason for the specs just do what I'm told. I'm not a smart man and have no problem admitting it, but I like hanging out with smart people, and I take thier advice a lot. You don't have to be smart in life just surround your-self with smart people and keep an open mind.
Thier are many ways to put a system together and get good sound, geuss there are many ways to run dedicated lines and achieve good power to. Hum, mudpuppy, what is your power conditioner?
vintage_tube
Vacuum Tube Passion
Besides Shunyata suggesting it what's the benefit of going to 10awg verses 12awg in your patricular case?? If you went with 12awg, do you believe you'd hear a difference????
beerdraft
Active Member
I really don't know about that, 10awg versus 12awg. Funny though, I accidentally plugged my right amp into a 15 amp non dedicated line from my old system and didn't realize it but my sound wasn't right. I played with speaker placement and then got tired and went away, when I came back down, I realized the amp plugged into wrong receptacle, fixed it and put speakers back where they were, all was good in the nieghbor hood. I think my buddy Bob suggested 10awg to, I normally listen to him.
vintage_tube
Vacuum Tube Passion
Besides pulling some number out of his ass -- What was his reason (pray-tell).????????