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Ground wire question for PC

107.4.59.207
Posted on May 21, 2016 at 10:13:42
mitch2
Audiophile

Posts: 1521
Location: Great Lakes
Joined: August 28, 2001
 In the example of a circuit with a 20A breaker, 10awg in-wall Romex to the outlet, and a power cord using 10awg positive and neutral conductors, feeding an amplifier with an 8A fuse on the input, what should control the size of the ground wire, from a safety standpoint, not necessarily what is required for UL but rather what is the adequate size of the ground wire, should it ever be needed?

Is the controlling factor to match the in-wall requirement for a 20A circuit (i.e., 12awg), to match the pos and neutral conductors of the PC (i.e., 10awg), or to match the 15A style plug and iec on the power cord (i.e., 14awg)?

One more related question, if the circuit is dedicated to the amplifier, does the 8A inlet fuse limit the current draw on that circuit to 8A?

Thanks.

 

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RE: Ground wire question for PC, posted on May 21, 2016 at 10:55:37
Duster
Manufacturer

Posts: 17117
Location: Pacific Northwest
Joined: August 25, 2002
 The ground conductor of a power cord should be the same gauge (or larger) as the live and neutral current carrying conductors. The safety factor of a power cord ground wire requires an efficient, low-impedance path to ground, so the ground conductor should provide equal (or greater) conductivity as what the live and neutral conductors provide.

 

Done, posted on May 21, 2016 at 15:01:10
mitch2
Audiophile

Posts: 1521
Location: Great Lakes
Joined: August 28, 2001
 Job finished. Six 10awg wires per cord, two cords for monoblocks.
They sound great right out of the gate.
I look forward to hearing more after they spend some time on the cooker.
Thanks for your help.

 

RE: Done, posted on May 21, 2016 at 15:09:54
Duster
Manufacturer

Posts: 17117
Location: Pacific Northwest
Joined: August 25, 2002
 What wire and connector products are you using for the project?

 

RE: Done, posted on May 21, 2016 at 20:39:52
mitch2
Audiophile

Posts: 1521
Location: Great Lakes
Joined: August 28, 2001
 Western Electric old stock 10awg wire, the same as used by Triode Wire Labs.
Two 10awg connectors per pole, with a star-quad, cross-connected geometry and the two 10awg ground connectors spiraled in the opposite direction to the four wire twist.
No shield since these are for monoblocks that will be connected directly to two 20A dedicated lines.
Furutech FI-11 (Cu) connectors.
They are now both on the cable cooker but they sounded great without conditioning. I simply cook all the cables I make to take the guesswork out of whether they will sound different when broken-in.
I have had great luck with these wires. I have a bunch and good thing because it is becoming harder to obtain. I am using two twisted pairs per speaker of the 10awg wire in a bi-wired configuration, so 7awg per speaker. I plan to try doubling up for an aggregate of 4awg per speaker but that is very likely overkill since they are only 1M long and running from mono-blocks sitting right next to the speakers. The sound of this wire is very organic with excellent body, particularly in the midrange. The bass is also a strong suit being textured, well-defined and powerful, without being overblown. Another strength is that the wire sounds very coherent overall. The low wattage crowd loves the 16awg variety as speaker cables. With my big amps and power-hungery Aerials, I like the 10awg wire best, but have tried the others too and they do sound nice.
Not too sure about the new Techflex that has natural and synthetic fibers. I bought it to use as a spacer to get the braid shield away from the conductors in some ICs that I make. I thought I would try it for these PCs. Maybe I will grow to like it. Not a big deal since nobody will probably notice them sitting behind the amps.



 

RE: Ground wire question for PC, posted on May 22, 2016 at 20:26:57
Jon Risch
Bored Member

Posts: 6659
Joined: April 4, 2000
Contributor
  Since: March 1, 1999
 For ground wires, a bus bar 1" thick would not be too much.

However, you are using silver, so your question should really be:
what is the minimum size I should use for a ground wire between component chassis?

The answer is this, use something no smaller than the AC cord ground wire of the larger cord used.

If the largest power cord in your system is a 16 Ga. cord, you could "get by" with two 18 Ga. wires in parallel, this would equal a total effective gauge of 15 Ga.

For best results, the largest amount of conductor you can afford, and make it low inductance.
A good way to do a low inductance ground wire is to braid together 2 or more separate wires, this will lower the self-inductance of the wire, to that below a single wire of the same effective total gauge. In order for this to be effective, the wires should be insulated from one another, even though they are carrying the same signal.

For instance, if budget allows, use three 18 Ga. separately insulated wires braided together, this will be equivalent to a total effective Ga. of better than 14 Ga.

Jon Risch

 

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