I'm going to leave it to the pros

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Chrisandalex1

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I'm going to leave it to the pros
« on: 31 Jan 2015, 02:02 am »
So I just threw away $120.00 worth of 10 Gauge THHN Wire.

I thought I would save some shipping and make my own braided 4/10 cable for my new dedicated outlets.  BIG MISTAKE #1

Then I decided to be lazy and have one of my house staff do the braiding.  She does my wife hair really nice.  Well, not 50' sections of 10 gauge wire.  Seriously, it looks like a 5 year old did it.  Totally my bad, but non the less, a bummer.  Mistake #2

Now I will leave it to Dave to make and send down to me.

It seemed like a good idea at the time...:)



Speedskater

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Re: I'm going to leave it to the pros
« Reply #1 on: 1 Feb 2015, 03:29 am »
Why would you braid it?
Twisting is the way to go!
And when you twist, just twist the Hot & Neutral.  Then tape the Safety Ground to the twisted pair.

**************************************
Ground Loops: The Rest of the Story
Bill Whitlock, AES Fellow  and Jamie Fox, P.E.

This paper was presented at the AES 129th Convention, 4-7 November 2010, San Francisco, CA, USA
ABSTRACT
The mechanisms that enable so-called ground loops to cause well-known hum, buzz, and other audio system
noise problems are well known. But what causes power-line related currents to flow in signal cables in the first
place? This paper explains how magnetic induction in ordinary premises AC wiring creates the small voltage
differences normally found among system ground connections, even if “isolated” or “technical” grounding is
used. The theoretical basis is explored, experimental data shown, and an actual case history related. Little
has been written about this “elephant in the room” topic in engineering literature and apparently none in the
context of audio or video systems. It is shown that simply twisting L-N pairs in the premises wiring can
profoundly reduce system noise problems.


http://xa.yimg.com/kq/groups/20963848/268252969/name/Whitlock-Fox+-+Ground+Loops+.pdf

DaveC113

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Re: I'm going to leave it to the pros
« Reply #2 on: 1 Feb 2015, 04:09 am »
In power cables I slightly prefer a litz braid to a twisted pair or star quad... the exact layout is kind of proprietary/unconventional use of a litz braid but it works well. :) I am going to make Chris a twisted cable for this application though. I run the ground wire around the hot/neutral in the opposite direction of the twist for neatness but running it parallel would be fine too.

Learning to work with wire and make perfect bends and braids does take some practice! You can't bend the wire directly, you need to hold it a few inches away from the bend and just guide it into place... that might not be clear but it's hard to describe.  :green:


Speedskater

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Re: I'm going to leave it to the pros
« Reply #3 on: 1 Feb 2015, 02:38 pm »
But a litz conductor has excellent very high frequency response. This is the opposite of a power conditioner that rolls off high frequency response. Yes, twisting the Safety Ground in the opposite direction would be good. A star-quad would also be good but for in-wall runs the NEC  won't permit it.

DaveC113

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Re: I'm going to leave it to the pros
« Reply #4 on: 2 Feb 2015, 12:58 am »
I was just referring to the 4-strand braid, but I do use litz wire* for my AC cables and it's significantly better for power cables vs the many other conductors I've tried. Litz wire can be built with different gauge wires to suit a particular frequency range so it does have low frequency AC applications too, but it's better known as a solution for skin effect issues at high frequencies.

Without going into too much detail, I do think that techniques that are used to build high frequency cables often apply to audio frequencies even if conventional wisdom would say many of those things shouldn't matter.  :green:   


*litz wire is made out of many strands of individually insulated wire arranged in such a way that there are no inner or outer strands through many different possible twisting and braiding processes. If I remember right there are 8 common types of litz wire construction.