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  • #31
    Macona,
    What about putting your power supply closer to the light and step down the power, lets say 120v/12v transformer less then 5 feet from each light. No voltage drop, smaller wire with less cost for the length you need. Just trying to think outside of the box.

    Mr. Fixit

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    • #32
      Take this as my opinion only, but anything other than real copper wire has no place in a low voltage system where significant currents will be drawn. And where the wire must be flexible- ya gonna use aluminum? Macona has a problem, yes- move power supply closer to the load is one option, double up the wire for less loss is another, use some 8 ga real copper wire which is actually suitable for the job- this is probably the best option. If what he had in the first place was actually copper wire, there would have been no problem. This is where my problem with fake wire comes in.

      Let's take another look at low voltage systems- your vehicle. Let's run some aluminum wire to the starter. Then we'll run some to the headlights. Might as well change the entire wire harness to aluminum wire. Oh, by the way, your engine is a 454. Let's see if you can actually get it to start. Ooh, what's that smoke coming from under the hood

      Hmm, can't drive. Let's go weld instead. Hook up that new aluminum welding wire. Awesome. UH OH, we seem to have a bad connection on the wire- it's burning over there by that pile of iron oxide. OOPS, THERE'S A THERMITE REACTION GOING ON

      How long do you think it will be before you get faked out when you buy some welding wire-

      I went and had a burger the other day. It didn't seem to be too bad, but I'm wondering- this doesn't really taste like beef. It doesn't even look like beef. IT ISN'T BEEF! But then, where does it say that it should be real beef- all you see in the menu is 'burger'. By the way, it's not ham either. You know- ham burger, hamburger, hangebur, WHERE'S THE HAM? I DON'T WANT HAM, I WANT BEEF!
      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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      • #33
        ...but his wire is "oxygen free"

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        • #34
          Why? if anything it avoids the issues of aluminum oxidation.
          What it doesn't avoid is the issue of expansion and contraction loosening the connection which is the main cause of problems with aluminum wire. All aluminum wire is already oxidized moments after it is drawn.
          Free software for calculating bolt circles and similar: Click Here

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          • #35
            You know- ham burger, hamburger, hangebur, WHERE'S THE HAM? I DON'T WANT HAM, I WANT BEEF!
            A Hamburger is named after Hamburg, Germany, not a pig.
            Free software for calculating bolt circles and similar: Click Here

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            • #36
              Originally posted by Evan
              What it doesn't avoid is the issue of expansion and contraction loosening the connection which is the main cause of problems with aluminum wire. All aluminum wire is already oxidized moments after it is drawn.

              Maybe not, but it has little practical effect on wires 8awg and above (mainly because of the terminations), which is why they are allowed and used profusely in the USA. Anti-oxident paste/grease is still required. For new construction I still see some copper in use at 8 and 6, sometimes 4. but rarely above that. Oh...., we had to run some 750mcm copper into a UPS because it was marked "copper only" - that was an expensive oversight on the part of the electrical contractor
              Last edited by lakeside53; 12-13-2011, 02:33 AM.

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              • #37
                macona, I'm curious...what's the deal with these lights that you have to use 12 volts for them? Why not 120V lights?
                Location: Saskatoon, Saskatchewan, Canada

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                • #38
                  'A Hamburger is named after Hamburg, Germany, not a pig.'

                  Interesting. Had never thought of that possible origin. So- it's German food
                  I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                  • #39
                    Think I am just going to get some real copper and see what happens first. A 15" piece should tell me what I want to know. If that works I will buy more.

                    This is for those plasma lights I mentioned a while back. Once I get something working I will post more on them.

                    -Jerry

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                    • #40
                      Aluminum wire is perfectly fine..... IF YOU HAVE THE RIGHT TERMINALS.

                      Otherwise it will create bad connections. It also does not always react so well to flexing.

                      A bad connection due to aluminum wire in a low voltage circuit probably will simply limit current, with a certain amount of heating. Not what you want, but possibly self-limiting.

                      In a higher voltage circuit, a bad connection will have nearly the full current forced through it, by the high "driving" voltage. That heats the connection more, which causes further oxidation, more resistance, more heating, and damages the surrounding material. A fire is a very common result.

                      Proper connections for aluminum reduce that risk. Even copper can have the problem, but with copper it is far less common. With copper, you pretty much need to do something actually wrong.... With aluminum, it is more like you merely have to fail to do something perfectly correctly.

                      You will notice that the electrical code requires a larger gauge wire for a given current in aluminum vs copper. If you needed 8 ga copper wire (40 or 45 A), you would need to use 6 ga aluminum.
                      CNC machines only go through the motions.

                      Ideas expressed may be mine, or from anyone else in the universe.
                      Not responsible for clerical errors. Or those made by lay people either.
                      Number formats and units may be chosen at random depending on what day it is.
                      I reserve the right to use a number system with any integer base without prior notice.
                      Generalizations are understood to be "often" true, but not true in every case.

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                      • #41
                        Originally posted by Jerry
                        In a higher voltage circuit, a bad connection will have nearly the full current forced through it, by the high "driving" voltage. That heats the connection more, which causes further oxidation, more resistance, more heating, and damages the surrounding material. A fire is a very common result.
                        Come on, low voltage will heat the connection just as well as high. It's the power available that matters. If it were otherwise welding wouldn't work and car wiring harnesses would never burn up.
                        Free software for calculating bolt circles and similar: Click Here

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                        • #42
                          never mind....
                          Last edited by lakeside53; 12-13-2011, 02:03 PM.

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                          • #43
                            Glad I stuck with 6 gage copper EISL wire for hooking up my 1k 24vac Reich and Vogel beam projectors.

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                            • #44
                              You might distribute power at high voltage and use a DC/DC converter at the point of use. I had some 12 volt to 5 volt dc dc converters from another project that were just a tiny 3 inch by 1.5 inch board with pins to plug into a bigger board. Each one could source 20 amps IIRC.

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                              • #45
                                Another alternative is to use a power supply with a remote voltage sense. That way the power supply will regulate its voltage at the load and compensate for the loss in the feed wires.

                                That is common in automotive alternators for instance. How does a 100+A alternator feed the power distribution point in the car through 10 feet of wire with only an 8 ga wire? It uses a remote sense wire that captures the voltage at the distribution point, and regulates to that. The main wire uses high temp insulation so it does not matter if it drops a couple of volts and makes some heat. If there is to be 14V at the distribution point, and 2V loss in the feed wire, the alternator produces 16V. 2V loss at 100A is 200W, which is a bunch of heat, but spread arcoss 10 feet of wire that you don't mind being 30C above the 70C ambient under the hood it is OK.

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