Kynar #30 Wire Wrap for DD?

[darkzero]

helllo
Was wondering if this 30AWG solid-copper core silver-plated wire wrap wire is sufficient enough to wire a Lux3 3C DD mod that I'm in the process of? And for future reference, how 'bout for a 5w DD mod?
I've seen a few mods using wire similar to this and others say to use 26AWG wire. Can this wire handle the current loads ok? The heatsink will be potted in and since this is a old style MagC there's no turning back (switch assy. comes out the front). Any comments are appreciated.

 

[dat2zip]

It's not necessarily the wire guage, but, the length.

While 30AWG may not be recommended, it's probably fine if the length is kept very short. If not, you can use two or three of them and twist them together to make a beefier wire.

Wayne

 

[ufokillerz]

I know for a fact that Mr.Bulk uses 30AWG wire, i use the same =)

 

[darkzero]

got it, txs!

 

[Rothrandir]

that's acceptable, but i prefer to use something closer to 20guage /ubbthreads/images/graemlins/wink.gif (i'm not sure of exactly what i use anymore, i think it's 22?)

also, stranded can be a little harder to work with, but i find it better to use as it's less likely to break inside your mod.

 

[Wylie]

D/C prefers stranded wire and would be the better choice I would think. The finer the strands the better and the more strands the better as well although it will not make much difference. Hey look guys I do know something about D/C after all. /ubbthreads/images/graemlins/icon3.gif

 

[red_robby]

i use the twisted pairs of cat 5 cable, or phone wire...

 

[LEDmodMan]

What Wylie said is true. Stranded wire carries the current better with less resistance. I used 20 gage stranded on my 3D DD TWAK, and I always solder to both LS terminals on each side for even better connections (this takes practice and a small soldering iron tip so that you don't melt the plastic LS bodies).

 

[RussH]

A conservative approach for power wiring uses 700 circular mils per amp. I'm not sure where that came from originally (some engineering magazine article is where I got it, IIRC). You can also find a boating chart (Coast Guard approved) showing maximum amps for DC wiring which is a bit higher than residential NEC limits.

This one will probably interest Joe Shmoe, since it may allow him to avoid smoking the wires to his lights:
You can use the following formula for determining the minimum possible wire size to use. It is a 'standard' formula for estimating wire sizes to use for a fuse.
33 * (I/A)^2 * S = log( (Tm - Ta) / (234 + Ta) + 1 )
I = current in Amperes
A = area of wire in circ. mils
S = time the current flows in seconds
Tm = melting point, C
Ta = ambient temp, C
The melting point of copper is 1083 C.
Substitute your desired temperature (instead of the melting temp.) and pick the time period S that suits your application.

My approach in this sort of application is to use the conservative values for Maximum Amps for Chassis Wiring, meant for wiring in air, with relatively short runs, no bundling. I found a chart on the web, but it is from the Handbook of Electronic Tables and Formulas.
guage max amps, chassis max amps power
20 11 1.5
22 7 .92
24 3.5 .577
25 2.7 .457
26 2.2 .361
27 1.7 .288
28 1.4 .226
29 1.2 .182
30 .86 .142

You can interpolate based on area. Rule of thumb is that area doubles (or halves) every three sizes although I prefer to look it up. For some reason, stranded wire is larger than solid for the same guage.

 

[EvilLithiumMan]

Yes - It really comes down to 'How hot are you willing to let the wire get?'

I once saw a .075" diameter piece of solder handle 400 amps of DC current. It was easy. It was sitting in a large bucket of ice water.

 

[DrJ]

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