15 amp would be typical. I am pretty sure 14 ga wire can handle 15 amps, 12 gauge wire can handle 20 amps and 10 gauge wire can handle 30 amps.
Most of the upgrades you have seen would have been people installing dedicated lines, with new wire. It is a very, very bad idea to just start swapping circuit breakers, and not change the wire gauge of the circuit.
As far as 30 amp lines go, their really is no reason to install them as dedicated lines. And yes I installed one. 10 gauge wire is fine/up to code but the outlets are only rated to 15/20 amps. 10 pounds of crap in a five pound bag. Plus the "code" plugs for 30 amps are not the neat after market ones you can buy, they are huge locking ones.
Also I really don't know of any 30 amp devices out their. I am not saying they are none, but the biggest I have seen requires a 20 amp line.
15 or 20 amps is a typical residential fuse rating (other than for large appliances -- my in-wall oven, for example, requires a 30 amp fuse). Bear in mind that, for most residential applications, a single circuit with a 15 or 20 amp fuse will be connected to a number of outlets and/or switches for fans or lights. Most home electronics do not require 30 amps. Dedicated lines to power supplies seldom need to be above 20 amps and even that is generous (of course, I'm doing just that just in case). A 15 amp dedicated line will support about 1,650 watts (110 volts times 15 amps) and that should generally be sufficient for most audio needs. I overkill everything and went for five 20 amp dedicated lines.
Sean makes some wonderful recommendations for a subpanel with a mix of 15 and 20 amp circuits. Bob Bundus (I hope I spelled that right) is extremely knowledgeable as well. Do a search on "dedicated line" and enjoy! Hope that help.
Mitch, check your local codes. Typical residential circuits are 15 and 20-amp for general power and lighting. Almost everywhere I know of you are not permitted to have more than one receptacle on a circuit rated greater than 20-amps. Not only that, a 30-amp branch circuit requires a 30-amp receptacle. Your conventional power cord plugs rated at 15 and 20 amp will not fit in a 30-amp receptacle.
No matter how power hungry your equipment is, they are all UL listed. This means that they are safe to operate in conventional 15 and 20-amp straight blade receptacles. And safety entails operation at peak performance.
Remember, the rating of a circuit is to protect it from overheating to the point of creating a fire hazard. Increasing wire size for a given current draw only reduces the voltage drop along the path. By going from a 20-amp #12 wire to a 30-amp #10 wire, the voltage drop only decreases by 0.024-volts per foot. Even if you have a 100-foot run, thats a 2.5-volt drop to the outlet; something a well designed power supply can handle with no problem. All day long.
Regardless of what the books and theory tell you, 12 gauge is NOT sufficient for a sustained 20 amp load over an extended length of cable. Count on using 10 gauge for a 20 amp circuit. I have measured sizable voltage drops with the resultant loss of power output when trying to pull 30 amps through 8 gauge at a length of less than 25 feet. This was using a large RF amplifier as the current draw, but it would be no different than if it were a large audio amp with a sustained duration note ( pipe organs, dance music aka "electronica", etc...).
As to products being UL listed and working off of a 15 or 20 amp circuit, that is true. HOWEVER, that would be under "normal use" conditions. It is possible that large amps running at very low impedances with a low efficiency load can pull more than 15 or 20 amps.
As a case in point, the "standard" Sunfire two channel amp rated for 300 @ 8, 600 @ 4, etc... WILL blow a 15 amp breaker if you are throttling it. If you supply a "real" 20 amps of current to this amplifier, it is capable of producing almost 1500 wpc RMS ( NOT "peak" ) @ 2 ohms. I have an actual review where they ran into this problem. Not only did the amp blow the factory supplied 10 amp fuses installed, they had to up the supply to 20 amps to drive the amp into clipping at 2 ohms. Once they did that, it was able to SUSTAIN a whopping 1450+ wpc.
Now if you compound that type of power draw by adding multiple channels to a high powered HT amp ( like the 200 / 400 wpc X 5 channel Sunfire Cinema Grand or the 400 / 800 wpc x 5 channel Sunfire Cinema Grand Signature ) and / or simply go to a larger 2 channel amp ( 600 / 1200 wpc Sunfire Signature ) or an amp that is both high powered and in-efficient ( Krell, Perreaux, Threshold's, etc... ), you can see where this is going. One might never get into such a situation unless they have low impdedance / low sensitivity speakers and / or like to listen at very loud levels.
In my specific case, some of my systems fall into ALL of those "bad" / "tough to deal with" categories. As such, i found out about this the hard way. About two months ago, i had an amp that was going into thermal shutdown due to current starvation. I sent it back to the factory for an inspection and everything checked out fine. It is at this time that they brought up the amount of current necessary to sustain the levels that i was running at. This forced me to do some checking on my end. Needless to say, I had to change how i had some things set up on my end to correct the situation. The good thing about this is that while they had the amp, they performed some newer upgrades / heavy duty modifications to the amp at no charge and even covered the return shipping. Sean
It is a very good idea to go to a 30amp circuit. You will notice a big improvement. If you do go to a 30amp breaker, you must use 10awg wire! Either that or you better get more fire insurance. I have installed 10awg on a 20amp breaker and was tripping the breaker all the time. I went to a 30amp breaker and never had any trouble since. Now I use three dedicated 30amp 10awg circuits and love it. A friend of mine installed 8awg wire and said it was an improvement over his 10awg wire. But use atleast 10awg. John
Speakerdude, I disagree; probably many insurance adjusters will also. It is not a good idea to run a 30-amp circuit regardless of any potential sonic improvements. It goes against electrical codes and for good reason. The limiting factor here is the rating of the receptacle - the 20A straight-blades (both slots up/down) cannot safely handle more than 20-amps continuous. If a fault occurs in the outlet box and the circuit starts drawing a continuous 27 or 28 amps, say, the required 20-A circuit breaker will clear the fault by tripping. An electrician can then determine what happened. If you have the 30-A breaker, it will happily let the excess current through and the mounting strap on the 20-A outlet, the plug and cord will heat up and possibly fail. This is a fire in the making.
The purpose of a circuit breaker is to protect the wire, period. It will not protect the outlet or your equipment. If all of your equipment draw more than 16-amps combined, then they need to be on multiple circuits because you will keep tripping the breaker. If one piece of equipment draws more than 20-amps, then something's wrong because the plug, cord and the transformer primary fuses are rated for a 20-amp (max) circuit. Hence the UL rating.
So if you go for #10 or #8 wiring (or even 500MCM for that matter) there might be benefits based upon your situation. However, your equipment will still draw only what's needed regardless of how much extra fat you have on the wires. But the circuit breaker has to prevent excess current from shooting through via faults or shorts. It's a safety thing, that's all.
No one has even mentioned line surge impedance. The lower the better, let me repeat that: The lower the better.
Theories aside - always use at least 10awg wiring - your ears will thank you.
Any faults drawing significant current will hardly draw the line at just below the fused value. If you're worrying about that then you really need something to do.
For Speakerdude:you right-if you will go from 10AWG to 8 or even 6-will be significant improvement-I already experimented with my dedicated line (I am electrician):just what you need do right-install 20 amp circuit breaker,because your receptacle 20amp(or 15amp,it's same).
Glad to see that others share my experiences. If some of you folks remember back to when we first started discussing dedicated lines on this forum, i was recommending 8 gauge for 20 amp circuits. I still think "heavier is better" but most folks think that 8 gauge is WAY overkill. It may be IF you have a very short run from the breaker box to the outlet. As such, i've "toned things down a bit" and figured that if i can get them to at least go up one step in commercial wiring ( from 12 gauge to 10 ), it would still be a step forward. When it comes to ANY type of power supply ( AC lines ARE "power supplies" ), bigger and lower series resistance is ALWAYS better. Sean
One problem with 8 gauge or lower is the difficulty in working with it. I'm a few weeks from moving into a house with dedicated 10 gauge lines. I have easy access to the same type of wire and am thinking about experimenting.
I could wrap and solder another 10 gauge line (hot to hot, neutral to neutral, ground to ground) just in front of the connections on both ends. There would then be two solid core lines running side by side. That would leave a 7 gauge run for most of the length and 10 gauge right at the connection points (well, maybe a couple of feet on either end depending on access capability). The total run is about 25 feet from the breaker box. Is this a crazy notion? At the end, it's always "let your ears decide", but this would be a bit of work and I'd rather avoid it if it won't make any difference. Thanks.
anything larger than #10 is very hard to work with especially solid conductor; another reason to stop there is that #8 or larger does not typically fit either the fusebox or outlet connections.
Oz - splicing smaller conductors onto the ends of a larger gauge run is probably not a good idea. You'll have two extra/un-necessary degrading connections, thus offsetting the benefits of the larger run in between.
Thanks Bob, I was hoping you'd say that. Your advice has saved me an hour or more in the crawl space ;-)