Wire Gauges and how to measure them.

[Den Moran]

Hi,everyone, and I hope you are keeping well in these dangerous times. I'm planning a few builds that need wiring extensions. I don't know how to order cable for the circuits, because they are always quoted in 'gauge size'. I've looked for a chart, but can only find the American sizes. Has anyone a simple method of doing this online, please? I just need to know the PHYSICAL size of the cable needed (the diameter), NOT the WVA/electronic calculations, Thanks, Den

[Kim Taylor]

I may be wrong on the teeny tiny sizes used in r/c installations, but my understanding was that electrical cables were sized by cross sectional area, e.g. 1.0mm, 0.75mm etc.

Wire gauge is, I thought, more applicable to piano wire or even wierdly sheet metal, e.g. 16 swg (standard wire gauge). The bigger the gauge number, the thinner the wire.

Don't know if that helps or not, sorry!!

Kim

Edited By Kim Taylor on 23/05/2020 09:54:06

[Former Member]

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[Tbone]

This site may be of use:

**LINK**

gives Imperial/metric diameters and the wire gauge used by most model manufacturers (AWG) ( probably not SWG)

Tbone

[Martin Harris - Moderator]

Remember that the conductors we use are multi strand circular section so for accurate measurement, work out the cross sectional area of a single conductor and multiply by the number of strands.

[Former Member]

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[Colin Bernard]

I find the 4-Max site great for this sort of info.

This page has a table giving area, diameter and maximum current for sizes from 8 to 20 AWG. This can then be extrapolated to other sizes.

On their servo wire page it shows them using 22AWG for standard servo wire, 26AWG for lightweight and 24AWG for extension leads

[wingcoax]

Not sure if they still do,BUT in the front of a lot of diaries(the pocket size)they used to print a lot of conversion tables and included was a list of wire sizes.

[FlyinBrian]

If indeed we are talking servo extension leads and unless you are talking very long runs for very powerful servos you would not need anything larger than 20AWG. I have flown models with 1 Metre ext leads with Hitec 7955 (24KG) servos using 20AWG extn leads.

More and clearer info would help us help you more ie distance involved, servos used etc.

You may well be talking about battery to ESC or ESC to motor leads????

[Colin Bernard]

Being a bit of a saddo curiosity has got the better of me and I have found that the relevant conversion formula for AWG to mm is

Diameter = 0.127 mm × 92^(36-n)/39

In Excel, if A1 holds the AWG value then the formula is 0.127*(92^((36-A1)/39)).

The cross sectional area is then PI()*(B1/2)^2 where B1 is the diameter.

There is no easy calculation for max current as it depends on type of wire, length, number of cores etc

[Former Member]

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[kc]

AWG is not the same as SWG.

AWG ( American Wire Gage) is different to SWG ( Standard Wire Gauge) so 6 AWG is about the same as 8 SWG.      8 AWG is about 10 SWG Very important if you are making undercarriage for an American plan and need to buy piano wire ( music wire ) which is usually sold in Britain in SWG.

Edited By kc on 23/05/2020 13:28:00

[Den Moran]

Thanks, everyone!

That's exactly what I needed, KC, and, combined with the charts/links suggested by Tbone, and Colin Bernard can proceed with confidence. I use Futaba-type leads for servos,so no problem there. Diolch yn Fawr, pawb,cadw yn saf iawn, Den, Cymru (Wales).