Wire gauge confusion

Sac Arrow

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I recently needed to order some wire to match some existing so I could wire in a switch to something.

So....

According to this chart https://www.powerstream.com/Wire_Size.htm a conductor diameter of 1.02 mm diameter is 18 gauge. Which, was what the conductor measured, approximately. It might have been 0.9, or 1.0, but I went with 1.02 and ordered some 18 gauge wire from the Zon.

What I got, however, was at least half the diameter. It was a Radio Shack label "hook up wire." Clearly placarded as being 18 gauge. Okay so it actually worked for what I needed it to do, but it obviously looks hokey.

What am I missing?
 
First, AWG is American wire gauge. It's measured in inch, not metric. Imported wire is most likely metric, not made to US wire gauges, so someone is probably rounding to the nearest gauge.

But it sounds like you got .5mm wire, or about 24 gauge, instead of 1mm wire, which is about 18 gauge. The larger is good for about 10A, more or less. The smaller one is mostly used for signaling, not power, as it's maybe 2A.
 
Sounds like the wire you received was mislabeled.
 
If it's going in an airplane I would strongly recommend you just get good quality MilSpec Tefzel wiring.

18 AWG = MIL-W-22759/16-18 ; rated at 11.4 amps.

Works great, looks great, up to spec and a pleasure to work with.

Best,
-
G


 
I went with 1.02 and ordered some 18 gauge wire from the Zon.

What I got, however, was at least half the diameter. It was a Radio Shack label "hook up wire." Clearly placarded as being 18 gauge.

What am I missing?

What was the insulation diameter, around 1mm? Perhaps Radio Shack hired the guy who used to do Sears' inflated vacuum cleaner and air compressor ratings...
 
What was the insulation diameter, around 1mm? Perhaps Radio Shack hired the guy who used to do Sears' inflated vacuum cleaner and air compressor ratings...

That's right. The wire I was trying to match had a conductor diameter of about 1 mm. The wire I received had an insulation diameter of about 1 mm.
 
Don't put anything labeled "Radio Shack" in or on an airplane that you will fly in. I would have either chucked or returned the wire as soon as I saw the marking.
 
Selling wire as 18ga based on the insulation thickness is a huge fire hazard. Trying to run 10a through that would be very bad.
 
Selling wire as 18ga based on the insulation thickness is a huge fire hazard. Trying to run 10a through that would be very bad.

You know what? I reviewed that product on Amazon for just that and you know what they did?

Rejected my review based on insensitity.
 
where is a good source (s) ( best prices ) for the tefzal wire ?
 
where is a good source (s) ( best prices ) for the tefzal wire ?
Depends on the size and quantity needed for best prices. Tefzal is used outside aviation and some of the best prices I got were from racing vendors. For small orders most aviation vendors like Spruce can be competitive.
 
where is a good source (s) ( best prices ) for the tefzal wire ?

If you don't care if it's aircraft rated, digikey. They may not have the absolute best prices on things, but they're reliable and they ship quickly.
 
I recently needed to order some wire to match some existing so I could wire in a switch to something.

So....

According to this chart https://www.powerstream.com/Wire_Size.htm a conductor diameter of 1.02 mm diameter is 18 gauge. Which, was what the conductor measured, approximately. It might have been 0.9, or 1.0, but I went with 1.02 and ordered some 18 gauge wire from the Zon.

What I got, however, was at least half the diameter. It was a Radio Shack label "hook up wire." Clearly placarded as being 18 gauge. Okay so it actually worked for what I needed it to do, but it obviously looks hokey.

What am I missing?
Is this what you ordered?

https://www.amazon.com/RadioShack-S...adio+shack+hookup+wire&qid=1638519754&sr=8-13
 
There's a very small chance that Radio Shack's error was caused by ignorance and not larceny. I purchased an antenna once that was listed as mounting to 1" pipe. Turned out the 1" pipe was too big, but 3/4" fit perfectly. 3/4" pipe has an O.D. of 1.05", so it seems someone at the antenna company got confused.
 
That review is a step in the right direction, but it might be more effective if the measured conductor thickness were included.

Well I guess I'm not the only one with that problem then.
 
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