IEC 60794-1-124:2025 contains test procedures, referred to as Method E24, for evaluating the behaviour of microduct cabling (microduct optical cable, fibre unit or hybrid cable etc.) when blown into a microduct or protected microduct. This document describes two blowing track layouts: Method A consists of two mandrels and two long straight sections in between (same curvature). Method B consists of 3 mandrels. The middle mandrel forces the cable to experience both left- and right-hand bending, which is a feature of any realistic blowing route. In addition, this document describes an optional procedure to check the capability of blowing out an installed cable. This first edition cancels and replaces Method E24 of the first edition of IEC 60794‑1‑21 published in 2015 and Amendment 1:2020. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) addition of a blowing route (see Figure 2) which includes a change in the direction of curvature. This was achieved by introducing a third mandrel;
b) addition of Annex A (Figure A.1 which shows a practical implementation of the blowing route;
c) addition of Annex B which describes the so-called Crash Test;
d) addition of Annex C which describes a cable blowing out procedure.
