ASTM D2656-00
(Specification)Standard Specification for Crosslinked Polyethylene Insulation for Wire and Cable Rated 2001 to 35 000 V
Standard Specification for Crosslinked Polyethylene Insulation for Wire and Cable Rated 2001 to 35 000 V
SCOPE
1.1 This specification covers a crosslinked polyethylene insulation for electrical wires and cables for conductor sizes 8 AWG (8.37 mm2) and larger. The base polymer of this insulation consists substantially of polyethylene.
1.2 This type of insulation is suitable for use on power cables in wet and dry locations at conductor temperatures not exceeding 90oC for continuous operation, 130oC for emergency overload conditions, and 250C for short-circuit conditions. It is considered suitable for all sizes and voltage classifications of single- and multiple-conductor power cables at voltage ratings of 2001 to 35000 V phase-to-phase at the 100 % insulation level and at voltage ratings of 2001 to 25000 V at the 133 % insulation level as listed in Table 1C of Test Methods D470.
1.3 Materials covered by this specification are not sunlight- and weather-resistant unless they are carbon black pigmented or contain an additive system designed for this protection.
1.4 In many instances the insulation cannot be tested unless it has been formed around a conductor. Therefore, tests are done on insulated wire in this standard solely to determine the relevant property of the insulation and not to test the conductor or completed cable.
1.5 Whenever two sets of values are presented, in different units, the values in the first set are the standard, while those in parentheses are for information only.
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An American National Standard
Designation: D 2656 – 00
Standard Specification for
Crosslinked Polyethylene Insulation for Wire and
Cable Rated 2001 to 35 000 V
This standard is issued under the fixed designation D 2656; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope * D 1711 Terminology Relating to Electrical Insulation
D 2765 Test Methods for Determination of Gel Content and
1.1 This specification covers a crosslinked polyethylene
Swell Ratio of Crosslinked Ethylene Plastics
insulation for electrical wires and cables for conductor sizes 8
2.2 ICEA Standard:
AWG (8.37 mm ) and larger. The base polymer of this
ICEAT-28-562 Test Method for Measurement of Hot Creep
insulation consists substantially of polyethylene.
of Polymeric Insulation
1.2 This type of insulation is suitable for use on power
cables in wet and dry locations at conductor temperatures not
3. Terminology
exceeding 90°C for continuous operation, 130°C for emer-
3.1 Definitions:
gency overload conditions, and 250°C for short-circuit condi-
3.1.1 For definitions of terms used in this specification refer
tions. It is considered suitable for all sizes and voltage
to Terminology D 1711.
classifications of single- and multiple-conductor power cables
3.2 Definitions of Terms Specific to This Standard:
at voltage ratings of 2001 to 35 000 V phase-to-phase at the
3.2.1 aging (act of), n—exposure of materials to air at
100 %insulationlevelandatvoltageratingsof2001to25 000
121°C for 168 h.
V at the 133 % insulation level as listed in Table 1C of Test
Methods D 470.
4. Physical Properties
1.3 Materials covered by this specification are not sunlight-
4.1 The requirements for the insulation are listed in Table 1.
and weather-resistant unless they are carbon black pigmented
or contain an additive system designed for this protection.
5. Electrical Requirements
1.4 In many instances the insulation cannot be tested unless
5.1 Order of Testing—Perform the partial-discharge, ac
it has been formed around a conductor. Therefore, tests are
voltage, insulation resistance, and dc voltage tests in that order
done on insulated wire in this standard solely to determine the
when any of these tests are specified. The sequence for other
relevant property of the insulation and not to test the conductor
testing is not specified.
or completed cable.
5.2 Partial Discharge (Corona)Extinction Voltage—Each
1.5 Whenever two sets of values are presented, in different
length of completed power cable with shielded conductors
units, the values in the first set are the standard, while those in
shall comply with the minimum level specified in Table 2.
parentheses are for information only.
Conduct the tests in accordance with Test Methods D 470.
5.3 AC Voltage Test—Subject the wires and cables to an ac
2. Referenced Documents
test voltage for a period of 5 min. Unless otherwise specified,
2.1 ASTM Standards:
omit this test if the dc voltage test described in 5.5 is to be
D 257 Test Methods for DC Resistance or Conductance of
2 performed. Test at a voltage of 125 V/mil (5 kV/mm) based on
Insulating Materials
the specified nominal thickness of insulation for the rated
D 470 TestMethodsforCrosslinkedInsulationsandJackets
2 circuit voltage, phase to phase. Conduct the test in accordance
for Wire and Cable
with Test Methods D 470.
D 1248 Specification for Polyethylene Extrusion Materials
3 5.4 Insulation Resistance—The insulated conductor shall
for Wire and Cable
have an insulation resistance equal to or greater than that
corresponding to a constant of 20 000 at 60°F (15.6°C). When
1 the temperature of the water in which the insulation is tested
This specification is under the jurisdiction of ASTM Committee D09 on
Electrical and Electronic Insulating Materials and is the direct responsibility of
Subcommittee D 09.18 on Solid Insulations, Non-Metallic Shieldings, and Cover-
ings for Electrical and Telecommunications Wires and Cables.
Current edition approved Sept. 10, 2000. Published November 2000. Originally Annual Book of ASTM Standards, Vol 08.02.
published as D 2656 – 67 T. Last previous edition D 2656 – 95. Available from Insulated Cable Engineers Association, P.O. Box 440, South
Annual Book of ASTM Standards, Vol 10.01. Yarmouth, MA 02664, or Global Engineering Documents, 15 Inverness Way, East
Annual Book of ASTM Standards, Vol 08.01. Englewood CO 80112.
*ASummary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 2656
TABLE 1 Physical Properties for Crosslinked TABLE 3 Accelerated Water Absorption Test
Polyethylene Insulation Requirements
Unaged Requirements: Electrical Method:
Tensile strength, min, psi (MPa) 1800 (12.4) Permittivity after one day, max 3.5
Elongation at rupture, min % 250 Increase in capacitance, max, %:
Aged Requirements: From 1 to 14 days 3.0
After Air Oven Test at 121 6 1°C for 168 h: From 7 to 14 days 1.5
Tensile strength, min, % of unaged value 75 Stability factor after 14 days, max 1.0
Elongation at rupture, min, % of unaged value 75 Alternative to stability factor:
Heat Distortion: Stability factor difference, 1 to 14 days, max 0.5
At 1216 1°C, max, % of unaged value:
4/0 Awg (107 mm ) and smaller (insulation on cable) 30
Larger than 4/0 Awg (107 mm ) (buffed sample of 15
accordancewiththeAcceleratedWaterAbsorptionTestsinTest
insulation)
Percent Hot Creep
Methods D 470. Conduct the Electrical Method Test at 60 Hz
Filled 100
with the water temperature at 75 6 1°C.
Unfilled 175
5.7 Pe
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