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Thread: Combined Wire Gauge Effectiveness

  1. #1
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    Default Combined Wire Gauge Effectiveness

    Since we are working with mostly low voltage, albeit possibly high amperage lighting, is it feasible to combine (twist) the ends of wires of a lower gauge to create a higher gauge wire to carry more amps? I have some nice 6 core 20 gauge wire packed nicely into 3 2-core shielded strands (Red/Black, White/Black, Green/Black). If I strip the ends of the Red/Black and twist then together, then crimp them into a ferrule or onto a Ray Wu or Delphi connector, according to this wire calculator the result would be about the equivalent of a 17 gauge wire. If i combine 4 20 gauge, it would be 14 gauge; all 6 would be 12 gauge.

    I would not totally rely on this to push the same amps of what a true solid equivalent AWG cable should do (but it would be an increase over the base 20 gauge), nor would I do this in a 120V application. Though what I'm reading states this reduces the resistance and the wires don't run as through a single wire. That said, my question is would this work for our intended use to bring power 10-15m to the start of a strand? Is there a bigger fire hazard doing it this way, or what would be the downfall of creating cables like this. I could twist 2/2/2 and have a V+/V-/D at 17 gauge from the controller. I could twist 3 & 3 and get a 15 gauge power injection cable. Or run 2 cables zip tied together, each with their 6 cores twisted together, so each cable would be about a 12 gauge equivalent. The ultimate goal is saving money as I have a lot of this cable at my disposal, and I'd like to utilize it without going out to buy 3 core 18 or 16 gauge wire rolls. I find a lot on Google searches of combining wire like this, I just wanted the community's take on any issues with blinky flashy.
    Last edited by AJR214; 02-02-2019 at 11:38 AM.

  2. #2
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    Default Re: Combined Wire Gauge Effectiveness

    Electricity doesn't care what the load is, only it's impedance. For DC power, the current carrying capacity is the same for n conductors with m/n unit area cross section as it is for 1 conductor with m unit area cross section. The downside to using multiple conductors is physical: more weight and overall volume (more insulation because more of the cross section consists of insulation on individual conductors, and generally an outer sheathing to keep the conductors together), more connections at the termination. For AC power there is a difference due to the skin effect, but in copper at common frequencies (50 or 60 Hz) you have to be talking about much more current than you will ever see for it to matter.
    Last edited by ags0000; 02-02-2019 at 03:57 PM.

  3. #3
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    Default Re: Combined Wire Gauge Effectiveness

    Combining wires (especially for power) is pretty common in this hobby. Many people use CAT-5 for sending data and power—combining several strands together for the V+ and GND.

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    Default Re: Combined Wire Gauge Effectiveness

    I recently considered doing this with Cat5 cable. My concern is that if you tie multiple wires together and put a fuse sized for the larger capability, then one wire breaks (i.e. cat5 cable one strand breaks or the termination isn't good), all of the current will go over a reduced number of wires, and the fuse won't protect those wires from overheating.

    In my cat5 scenario, I was going to put a fuse for each strand of wire.

  5. #5
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    Default Re: Combined Wire Gauge Effectiveness

    I have no problem doing this with stranded wire but solid core can be risky. A 20 gauge wire can break easily, especially at the point where it’s crimped into the ferrule. You can’t see that it’s broken and will expect it can still handle the same amount of current. Stranded wire has less risk of this happening. If one or two conductors are broken then you still have the rest to carry the load. If I wanted to use multiple conductors on something like solid core data cable then I would probably put a connector on it and make a PCB to break it out.

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    Default Re: Combined Wire Gauge Effectiveness

    Quote Originally Posted by mattrob View Post
    I recently considered doing this with Cat5 cable. My concern is that if you tie multiple wires together and put a fuse sized for the larger capability, then one wire breaks (i.e. cat5 cable one strand breaks or the termination isn't good), all of the current will go over a reduced number of wires, and the fuse won't protect those wires from overheating.

    In my cat5 scenario, I was going to put a fuse for each strand of wire.
    First best practice is to use stranded CAT5. A lot less likely to break. As for fusing each cable, I'm thinking over protection......say you have 18 gauge stranded wire (I'll pick 7 strands to make it easy) and due to ruff handling you break 3 of those strands.....fusing each strand wouldn't help. Not saying don't, just feeling much more work than it is worth.
    In Lights Therapy

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    Default Re: Combined Wire Gauge Effectiveness

    Thanks for the quick replies and information. I thought I've read about people twisting Cat5 together. I'll start with the 6 core (stranded) wire that i have for free, then work into Cat5 cable if I need more.

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    Default Re: Combined Wire Gauge Effectiveness

    Quote Originally Posted by AJR214 View Post
    Thanks for the quick replies and information. I thought I've read about people twisting Cat5 together. I'll start with the 6 core (stranded) wire that i have for free, then work into Cat5 cable if I need more.
    One more thought...if you do 2/2/2 - v+/v-/d do 2/2/1-1 v+/v-/d & v-
    Data doesn’t need the capacity that power needs, and it loves to be twisted with ground (your v-) plus it gives you the proper ground return for data without using some of powers....does not need to be isolated, so net result is 2/3/1
    In Lights Therapy

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    Default Re: Combined Wire Gauge Effectiveness

    ..Nevermind, OP had same link...
    Last edited by mc in FDale; 02-02-2019 at 05:17 PM. Reason: redundant

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    Default Re: Combined Wire Gauge Effectiveness

    One additional caution. All of this discussion has been about combining equal sized wires to create a larger logical wire. The formula for this works well and it is safe to do.

    However, combining wires of different sizes is a bit trickier. For example, taking a 22 AWG wire and a 16 AWG wire will not result in a logical wire that has greater carrying capacity than just the 16 AWG wire. There comes a point where the ratio between the impedances in the wires results in all of the current going through one wire and effectively ignoring the others. The greater the impedance mismatch between the wires making up the bundle the greater the chance (not so much chance as mathematical certainty) that the smaller wire will have no impact on overall carrying capacity.


    2019 - Going to visit my Daughter in New Zealand (again). I will be dark for the 2nd year in a row. Sigh..

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