How to determine gauge of wire

Status
Not open for further replies.
C

cyrusthevirus

New Member
I have a circuit with a power supply of 58V @ 1A so the total wattage is 58 Watts. The wire will be running about 20 feet from power supply to led. What gauge wire should I use?
 
To be determined by the load, so what will the load current be? Additionally, just a single LED? Pretty high voltage for a single LED.

Ron
 
Wire Gauge Resistance per foot

4 .000292
6 .000465
8 .000739
10 .00118
12 .00187
14 .00297
16 .00473
18 .00751
20 .0119
22 .0190
24 .0302
26 .0480
28 .0764

Say you want a drop of under 0.5v (~1%).

That means a resistance of 0.5 ohms/20ft, or 0.025ohms/ft. Sounds like 22 gauge or thicker will do. Note my calculations do not include heating, but at such low currents, this won't be much of an issue.

Andrew
 
Where is the current-limiting for the LEDs? If you are using a ballast resistor, I submit that you don't care what the voltage drop along the wire is, as long as the wire does not self-heat significantly. You can always reduce the ballast resistor slightly to make up for the wire resistance; at only 750mA you can use #22 to #28 AWG.
 
Last edited:

Thanks everyone. I will go with 22 AWG. Does anyone know of a common molded cable such as a VGA cable with at least 6 conductors and at least 22 AWG? (The highest quality VGA cables I could find were 24 AWG).
 
Finding 6 conductor cable is usually a matter of looking in a catalog or a vendors website. This is not Home Depot stuff, as far as I know.
 
You can consider something cheap and simple like Alpha Cable #1176C which is this stuff. Also you are looking at 100' spools.

You may find some 6 conductor HVAC cable at Lowes or Home Depot in AWG 18 or 20 sold by the foot but I am not sure. I know you can find 4 conductor. Worst case two runs of 4 conductor?

Ron
 
I got to actually thinking about this. How about everyday CAT 5 or CAT 6 solid conductor cable? Cheap and abundant anywhere, and it has 8 conductors. That should work. You don't need fancy stuff for this.

Ron
 
Last edited:
Does the fact that it is stranded have any negative impact? CAT 5 is also 24 AWG. Would 22 AWG be any better or am I still in an acceptable range for wattage?
 
Stranded wire survives flexing much better than solid core. Think about how you are going to route the wire before you buy it.
 
Considering the low current as was posted anything between 24 and 28 would likely work fine. CAT 5 and CAT 6 should come in stranded or solid and either flavor should work. The stuff again is cheap and plentiful. Something to consider is since you have 4 pairs (8 conductor) and your LEDs will likely share a single common you can use a pair in parallel as the common.

Ron
 
Status
Not open for further replies.

Similar threads

L
spot weld wire to wire?
Replies
15
Views
2K
ChrisP58
  • Question
How can a clamp meter be used to measure the amperage of a wire or cable from the phase and neutral of two strands?
Replies
6
Views
2K
Nigel Goodwin
A ferrite core & 6' of 24AWG enameled wire
Replies
7
Views
2K
ThomsCircuit
V
  • Question
How to get SOF, EOF, CRC etc of a CAN Frame.
Replies
8
Views
2K
Papabravo
Z
  • Question
How to power on this weird circuit?
Replies
6
Views
430
Tony Stewart
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…