IEC 60332-3-24 pdf free download

IEC 60332-3-24 pdf free download.Tests on electric and optical fibre cables under fire conditions – Part 3-24: Test for vertical flame spread of vertically-mounted bunched wires or cables – Category C.
5.3 Mounting of the test sample
5.3.1 Cables having at least one conductor above 35 mm2
For cables having at least one conductor with a cross-section exceeding 35 mm, each test piece shall be attached individually to each rung of the ladder by means of metal wire (steel or copper). For cables up to and including 50 mm diameter, use wire between 0,5 mm and 1,0 mm in diameter. For cables above 50 mm diameter, use wire between 1,0 mm and 2,5 mm in diameter.
Test pieces shall be attached to the front of the standard ladder in a single layer up to a total maximum width of 300 mm with a space between each test piece of 0,5 times the cable diameter but not exceeding 20 mm (see Figure 1). There shall be a minimum distance of 50 mm between the edge of the test sample and the inside of the ladder uprights.
When mounting the test pieces, the first test piece shall be positioned approximately in the centre of the ladder and further test pieces added on either side so that the whole array of test pieces is approximately centred on the ladder.
Mount all test pieces on the ladder with the bending (due to bending of the cable on the reel), if any, in the same direction, towards the back side of the test chamber as much as possible.
To achieve straight test pieces between the steel rungs below and above the burner position, it is permitted to fix the test pieces to an additional horizontal support 200 mm to 300 mm lower than the steel rung below the burner position.
NOTE The objective is to improve the repeatability and reproducibility of the test.
5.3.2 Cables having conductors 35 mm2 and below and optical cables
For cables having all conductors with cross-sections of 35 mm2 or smaller and optical cables, each test piece shall be attached, either individually or as part of an array, to each rung of the ladder by means of metal wire (steel or copper) between 0,5 mm and 1,0 mm in diameter.
Test pieces shall be attached to the front of the standard ladder in touching formation in one or more layers up to a maximum total width of 300 mm. There shall be a minimum distance of 50 mm between the edge of the test sample and the inside of the ladder uprights.
When mounting the test pieces, the first test piece or array of test pieces shall be positioned approximately in the centre of the ladder and further test pieces or arrays added on either side so that the test sample is approximately centred on the ladder.
Mount all test pieces on the ladder with the bending (due to bending of the cable on the reel), if any, in the same direction, towards the back side of the test chamber as much as possible.
To achieve straight test pieces between the steel rungs below and above the burner position, it is permitted to fix the test pieces to an additional horizontal support 200 mm to 300 mm lower than the steel rung below the burner position.
In order to ensure that the test pieces are straight on the ladder, the test pieces shall be maintained under tension manually while attaching the test pieces to the rung of the ladder by means of a metal wire.
NOTE The objective is to improve the repeatability and reproducibility of the test.
If a second (or more) layer of test pieces is required after the full width of the ladder has been utilized for the first (or following) layer, then the first test piece or array of test pieces in the second (or following) layer shall be positioned approximately in the centre of the ladder and further test pieces or arrays added on either side so that the second (or following) layer is approximately centred on the ladder.IEC 60332-3-24 pdf free download.