CMA for Tefzel wire

I assume that the «Conductor sizes» document that you provided in the «Splicing» module of the «Wiring Fundamentals» course is not acceptable to M22759/32 Tefzel wire.

First of all, I saw that in the «Table A. CMA of Typical Conductors» on page 24 of the Raychem catalog (ENG_DS_2347480-1_raychem-devices_0219.pdf), the CMA of 20AWG wire is 1216. But in your document CMA of 20AWG wire is 1006. 20AWG gauge used as an example, and I will use it for further explanations.

Then I tried to manually calculate CMA for it.

Referring to the «TE Wire Calculations and Instructions» document (ENG_CS_1773096_SEC12_INDEX_0210.pdf), the formula looks like CMA = D^2 x N x 1550.003

Referring to M22759/32 datasheet, there are 19x32AWG strands in M22759/32-20 wire (20AWG).

D = 0.202mm (32AWG)

N = 19

CMA = 0.202^2 x 19 x 1550.003 = 1201

1201 is closer to 1216 from the Raychem table than 1006 from yours.

Can I use CMA values from your document, or I must calculate it by myself for Tefzel wire for a more precise splice size selection?

Yeap, M22759/32 has a bit more copper in it usually, and often a different arrangement of the stranding (smaller sizes, but more of them). The document provided is a guide to most scenarios, but absolutely go by the documentation specific to what you're using if its available :-).

Thanks, Zac. Glad to see your answers at this forum!