WCA May 2014

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Wire & Cable ASIA – May/June 2014
Therefore, this cable meets the standard of hot-set
properties in the bridging method that did not perform
electron beam irradiation in polyolefin materials.
The main physical properties of a newly developed cable
for photovoltaic power generation are introduced below.
3 Test Method
3.1 Hot-set Test
A hot-set test was performed in conformance to the
IEC60811-2-1 standards. An insulating tube-shaped
piece and a sheath tube-shaped piece were cut out from
a cable. The test pieces were hung at 20ºC in an oven.
A load of 20 N/cm2 was applied to the test pieces.
An elongation percentage was measured 15 minutes later.
After that, the load was removed. After the temperature
of the oven was restored, the test pieces were removed
and cooled down to room temperature. An elongation
percentage was measured again.
Test results are judged as acceptable if an elongation
percentage under load is lower than 100 per cent and
if an elongation percentage after the removal of load is
25 per cent.
3.2 Heat Deterioration Properties
An insulating tube-shaped piece and a sheath tube-
shaped piece were cut out from a cable. The time when an
elongation residue percentage had reached 50 per cent at
each deterioration temperature of 180ºC, 158ºC and 136ºC
was verified. Judging from the Arrhenius curves of these
three standards, the temperature at which an elongation
residue percentage after 20,000 hours of deterioration had
reached 50 per cent was verified. Test results are judged
as acceptable if the above-mentioned temperature is
higher than 120ºC.
3.3 Single Vertical Combustion Test
A single vertical combustion test was performed in
conformance to the IEC60332-1-2 standards. A 60mm
sample was burned with a specified burner so that the
lower part of the sample was ignited for 60 seconds.
After the flame was detached, the sample was left
unattended until the flame was extinguished by itself.
After the extinguishing was completed, the upper edge of
a carbonised length was measured from the upper part
of the sample, and the lower edge of a carbonised length
was measured from the upper part of the sample.
Each carbonised length is judged as acceptable if it is
longer than 50mm or shorter than 540mm, respectively.
4 Test Results
4.1 Hot-set Test
The results of the hot-set test are shown in Table 1.
Judging from the table, it was verified that this cable has
excellent high temperature heat resistance without the use
of electron beam irradiation.
4.2 Heat Deterioration Properties
Table 2 shows a temperature at which an elongation
residue percentage reaches 50 per cent after 20,000
hours of deterioration as determined by Arrhenius curves.
Judging from the table, it was verified that this cable has
excellent heat deterioration properties.
4.3 Single Vertical Combustion Test
The results of the single vertical combustion test are
shown in Table 3. Judging from the table, it was verified
that this cable has excellent incombustibility because the
spread of fire did not occur in the upward and downward
directions.
4.4 Other Characteristics
Other characteristics of the newly developed cable are
introduced on the next page.
Test Required Developedwire
INSULATION
Hot-set test at 200º for 15 min
Under load of 20N/cm2 (%) 100> 30
After unloading (%) 25> 3
JACKET
Hot-set test at 200º for 15 min
Under load of 20N/cm2 (%) <100 29
After unloading (%) <25 4
Test Required Developed wire
INSULATION
>120 121.2
JACKET
>120 121.9
Test Required Developedwire
CABLE
Vertical flame spread resistance
Length from top of cable to point
of ending carbonisation (mm)
Length from top of cable to point
of starting carbonisation (mm)
>50
<540
370
510
❍
❍ Table 1: Hot-set test
❍
❍ Table 2: Thermal endurance properties
❍
❍ Table 3: Single vertical combustion test
❍
❍ Figure 1: End strip workability
Developed wire