AC Power Cord Wire Gauge


I guess this is a two-fold question dealing with the amount of AC power flowing through normal - that is, not special 20 amp dedicated lines - 15 amp house circuits. I'm guessing that these lines use 14 gauge wire, with a 15 amp breaker, to say a duplex receptacle. One conversion I read is that 15 amps X 120 = 1,800 watts. So, the first question is: If you plug a surge protector/power strip/power conditioner into one outlet in the duplex receptacle and then plug, say, four audio components into that "power strip" can they draw the full complement of AC power available (i.e., the power isn't split between the two outlets in the receptacle)? If you plug another component into the other outlet does it reduce the power available to the "power strip"?

Second, if the house wiring to the duplex receptacle is 14 gauge from the electrical panel, does it make any difference if you buy heavier (say a 10 gauge) after-market audiophile power cords for the audio components? Or, would a 14 gauge cord - the same gauge as the house wiring - be sufficient? Can a 10 gauge cord flow more power than is available through the house wiring at 14 gauge?

Thanks.
kencalgary
Check out what this EE has to say about power cords.
Interesting writeup, Jea. Thanks for calling it to our attention.

Pretty much all of it rings true to me. And I think that he really manages to get across the notion that the perspectives most of us (both EE's and non-EE's) tend to bring to these issues are overly simplistic. And he provides some good insight into why stock power cords can be usually, or at least often, be expected to underperform.

He does not, by the way, address in any explicit way the issue of the benefits or lack thereof of using a power cord that is heavier gauge than the wiring inside the walls.

Putting aside his extensive technical verbiage, I would summarize his main points as follows:

Most house wiring is either 12 gauge or 14 gauge, while many OEM cords are 18 or at best, 16 gauge. Most OEM cords do not have shielding or any provision for reducing radiated EM fields, do not have premium AC outlet plugs or premium IEC plugs for better electrical contact at these junctions....

As always, the bottom line is: you have to listen for yourself, and see if their is any benefit for you, on your system, with your listening habits....

Some of the cord/cable manufacturers get carried away with using only the very finest materials and assembly techniques, carrying over the technology and costs from their high end audio interconnects and speaker cables. Is this necessary? I don't know, I will not discount it out of hand. Does it make the cords cost a lot? Yes.

Regards,
-- Al
Al,
Risch's post on AA was from Nov 2000. Lot has been learned since then regarding the effects a power cord can have on a piece of audio equipment.



This may have something to do with the larger conductor size in PCs. Don't know for sure though.
Question: There is a tremendous amount of electrical interference and EMI coming from outside the home that we need to protect our equipment from. This implies that we need some sort of power conditioner or filter to protect the equipment.
Answer: Most of the EMI that affects the audio quality of a system is generated by the audio components themselves. EM waves that travel through space dissipate in power as the square of the distance from the source and very high frequencies that propagate through the power circuit do not survive for long. Power lines present a high impedance to Mhz and Ghz signals due to the relatively high inductance of power lines.

A primary source of audible sonic degradation is caused by the power supplies. Most components use FWBR (full wave bridge rectifier) power supplies that generate an incredible amount of transient noise when the rectifiers switch on and off. The design of a power cord can significantly affect the reactance of these signals within the power supply. Because the power cord is part of the primary winding of the power transformer, the transition between the various metals used in a PC can cause EM reflections and diode-like rectification of the noise impulses as they propagate away from the power supply. If the PC presents a high impedance to these signals they will be reflected back into the power supply where they will intermodulate increasing the high frequency noise levels of the component. Most power supply filters are ineffective at blocking very high frequency noise components and much of it is passed through to the DC rails. The sonic effects of this include: high background noise levels, blurred or slurred transients and a general lack of clarity and purity of the sound or visual image.
Quote taken from shunyata info
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Thanks Jea for adding some valuable information to my (limited) knowledge of powering my equipment. I also appreciate the reference to Jon Risch's info which is also very useful to me. Hope you all have a Happy New Year. Many thanks.
This may have something to do with the larger conductor size in PCs. Don't know for sure though.

While everything in the quote from Shunyata sounds correct to me, it's dealing with effects at rf frequencies, which I don't think would be a function of gauge per se (at least among the gauges we have been discussing).

Regards,
-- Al