AWG - American Wire Gauge
AWG refers to the diameter of the wire
AWG Dia mm Area mm Resistance ohm / m
K Type wire
10 2.59 5.26 0.19
20 0.81 0.52 1.92
30 0.255 0.0509 19.63
charlespax indicates the T400 is accurate with thermocouple resistances up to
about 100 ohms.
The 1 meter 30 AWG K Type probe has a resistance of about 22 ohms while the 10 meter
length has a resistance of about 200 ohms which is above the limit of accuracy of the device.
When using 30 AWG wire he recommends keeping the length to less than 3 meters.
Within reason the only negative with using thicker wire is cost and availability.
I don’t know of any sources for thicker K type Thermocouple wire at a reasonable price.
Using a 10 meter length of 30 AWG wire will probably cause a reading error of about
+8 deg C.
(I’m not an expert in this field, all the above information came from this forum and
the internet)