Selecting wire size

[Demon]

Hi,

I'm looking for ideas concerning wiring from a PC PSU to custom panels:

• 5 VDC
• about 5 amps (mostly from LEDs, 7-segment LEDs and LCDs)
• for interior use
• 4 wire; pos, neg, TX, RX
• under 5ft long
• Canada/USA specs

I've been googling but getting all sorts of varying results. I've seen references of single-strand 22awg wire could withstand up to 8 amps, but that sounds a bit high for a noob like me. Ideally I would like to use s-s 22awg telephone wire, but not if I'm heading for disaster.

Robert

[dhouston]

Try the chart on this page. I think you want the power transmission column.

[Heckler]

If you are going less than 5 feet... I would think you could go more on the values in the "Chassis Wiring" column. ie awg 22 to awg 18. Depending on how much voltage drop you can stand.

Normal house wiring is awg 12 for 20 Amp circuits and AWG 14 for 15 Amp circuits. I think the "power transmission" column is geared toward minimal voltage loss over long distances.

[Demon]

That's one of the pages I found while googling "22awg wire size" and was unsure what to make of chassis wiring (7 amps) VS power transmission (0.92 amps). That's one huge difference, wasn't sure which one applied to me.

This is for a gaming application; it's just simulating keyboard inputs and displays. I was surprised how quickly 7 segment LEDs chew up current. I'm starting to think about small LCDs instead, but that's totally not the look of aviation radios and such.

Robert

[Demon]

I think I might have found a cheat out of this; connection in series.

I could use short cables from the main panel (sits behind the center monitor) to the left and right panels on each side. Then thick power traces along the PCBs, short cables out the other end to the next panels on either side of the user (the panels wrap around the user, like an airplane cockpit).

The trick seems to be external cables as short as possible.

Robert

[dhouston]

That's one of the pages I found while googling "22awg wire size" and was unsure what to make of chassis wiring (7 amps) VS power transmission (0.92 amps). That's one huge difference, wasn't sure which one applied to me.

Chassis wiring is inside an enclosure and usually very short while power transmission wiring may be exposed and of undetermined length. I suspect the latter is concerned with the heat generated as a result of voltage loss.

[rsocor01]

That's one of the pages I found while googling "22awg wire size" and was unsure what to make of chassis wiring (7 amps) VS power transmission (0.92 amps). That's one huge difference, wasn't sure which one applied to me.

This is for a gaming application; it's just simulating keyboard inputs and displays. I was surprised how quickly 7 segment LEDs chew up current. I'm starting to think about small LCDs instead, but that's totally not the look of aviation radios and such.

Robert

The table that you are referring to is from the National Electrical Code (NEC) handbook which applies to the US. This table is for 110 Volts AC. If you are talking about using 5 Vdc then the allowed amperage is going to be a lot bigger.

Robert