Background Image
Table of Contents Table of Contents
Previous Page  57 / 64 Next Page
Basic version Information
Show Menu
Previous Page 57 / 64 Next Page
Page Background

55

www.read-wca.com

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/cm

2

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 Developed

wire

INSULATION

Hot-set test at 200º for 15 min

Under load of 20N/cm

2

(%)

100>

30

After unloading (%)

25>

3

JACKET

Hot-set test at 200º for 15 min

Under load of 20N/cm

2

(%)

<100

29

After unloading (%)

<25

4

Test

Required

Developed wire

INSULATION

>120

121.2

JACKET

>120

121.9

Test

Required Developed

wire

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