IEC 60332-3-23:2000 pdf download

IEC 60332-3-23:2000 pdf download.Tests on electric cables under fire conditions一 Part 3-23:Test for vertical flame spread of vertically-mounted bunched wires or cables – Category B.
3 DefinitIons
For the purpose of this part of lEG 60332 the following definitions apply. The definitions are taken from lEG 60695-4.
3.1
Ignition source
source of energy that initiates combustion
3.2
char
carbonacoous residue resulting from pyrolysis or incomplete combustion
3.3
flame spread
propagation of a flame front
4 Test apparatus
4.1 General
The apparatus specified in IEC 60332-3-10 shall be used.
4.2 Ignition source
The ignition source shall be one ribbon-type propane gas burner as specified in
IEC 60332-3-10.
5 Test procedure
5.1 Test sample
The test sample shall comprise a number of test pieces of cable from the same production length, each having a minimum length of 3,5 m.
The total number of test pieces in the test sample shall be that number required to provide a nominal total volume of non-metallic material of 3.5 I/rn of test sample.
The test sample shall be chosen within the limitations given in annex A
The test pieces forming the test sample shall be conditioned at a temperature of (20 ± 10) °C
for at least 16 h before commencing the test. The test pieces shall be dry.
5.2 DetermInation of the number of test pieces
In order to calculate the appropriate number of test pieces. It is necessary to determine the volume per metre of non-metallic material of one test piece.
A length of cable which shall be not less than 0,3 m long is carefully cut to ensure that the surfaces are at right angles to the cable axis, thus enabling precise measurements of its length.
The total volume, V. of the non-metallic materials contained in 1 m of cable is equal to the sum of the individual volumes V1. V2. etc.
The closest integer (0,5 and above corresponding to 1) of the number of test pieces to be mounted is obtained by dividing the volume per metre specified in 5.1 by the total volume, V, of non-metallic material per metre of cable.
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 diameter. For cables above 50 mm diameter, use wire between 1,0 mm and 1,5 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 at 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 ot the ladder and further test pieces added on either side so that the whole array of test pieces is approximately centred on the ladder.
5.3.2 Cables having conductors of 35 mma and below
For cables having all conductors with cross-sections of 35 mm2 or smaller, 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.