ASTM D2656-20

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D2656 − 13 D2656 − 20
Standard Specification for
Crosslinked Polyethylene Insulation for Wire and
Cable Rated 2001 to 35 000 V
This standard is issued under the fixed designation D2656; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This specification covers a crosslinked polyethylene insulation for electrical wires and cables for conductor sizes 8 AWG
8 AWG (8.37 mm ) 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
90 °C for continuous operation, 130 °C for emergency overload conditions, and 250 °C 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 35 000
V 35 000 V phase-to-phase at the 100 % insulation level and at voltage ratings of 2001 to 25 000 V 25 000 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,stated, in different units, the values in the firstfirst set are the regarded as standard,
while those the values in parentheses are provided for information only.only and are not considered standard.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D470 Test Methods for Crosslinked Insulations and Jackets for Wire and Cable
D1248 Specification for Polyethylene Plastics Extrusion Materials for Wire and Cable
D1711 Terminology Relating to Electrical Insulation
D2765 Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics
This specification is under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and is the direct responsibility of Subcommittee
D09.07 on Electrical Insulating Materials.
Current edition approved Nov. 1, 2013Oct. 1, 2020. Published November 2013October 2020. Originally approved in 1967. Last previous edition approved in 20062013
as D2656 – 06.D2656 – 13. DOI: 10.1520/D2656-13.10.1520/D2656-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary 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
D2656 − 20
2.2 ICEA Standard:
ICEA T-28-562 Test Method for Measurement of Hot Creep of Polymeric Insulation
2.3 UL Standard:
UL 2556 Wire and Cable Test Methods
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this specification refer to Terminology D1711.
4. Physical Properties
4.1 The requirements for the insulation are listed in Table 1.
5. Electrical Requirements
5.1 Order of Testing—Perform the partial-discharge, ac voltage, insulation resistance, and dc voltage tests in that order when any
of these tests are specified. The sequence for other testing is not specified.
5.2 Partial Discharge (Corona) Extinction Voltage—Each length of completed power cable with shielded conductors shall comply
with the minimum level specified in Table 2. Conduct the tests in accordance with Test Methods D470.
5.3 AC Voltage Test—Subject the wires and cables to an ac test voltage for a period of 5 min. Unless otherwise specified, omit
this test if the dc voltage test described in 5.5 is to be performed. Test at a voltage of 125 V/mil (5 kV/mm) based on the specified
nominal thickness of insulation for the rated circuit voltage, phase to phase. Conduct the test in accordance with Test Methods
D470.
TABLE 1 Physical Properties for Crosslinked
Polyethylene Insulation
Unaged Requirements:
Tensile strength, min, psi (MPa) 1800 (12.4)
Tensile strength, minimum, psi (MPa) 1800 (12.4)
Elongation at rupture, min % 250
Elongation at rupture, minimum % 250
Aged Requirements:
After Air Oven Test at 121 ± 1 °C for 168 h:
Tensile strength, min, % of unaged value 75
Tensile strength, minimum, % of unaged value 75
Elongation at rupture, min, % of unaged value 75
Elongation at rupture, minimum, % of unaged value 75
Heat Distortion:
At 121± 1 °C, max, % of unaged value:
At 121± 1 °C, maximum, % 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
insulation)
Larger than 4/0 Awg (107 mm ) (buffed sample of 15
insulation)
Percent Hot Creep, max
Percent Hot Creep, Maximum
A
Filled 100
B
Unfilled 175
Percent Hot Set, max
Percent hot set, maximum
A
Filled 5
B
Unfilled 10
A
Filled indicates a crosslinked polyethylene insulation that contains 10 % or
greater carbon black and/or mineral fillers.
B
Unfilled indicates a crosslinked polyethylene insulation that contains less than
10 % carbon black and/or mineral fillers.
Available from The Insulated Cable Engineers Association, Inc. (ICEA), P.O. Box 1568, Carrollton, GA 30112, http://www.icea.net.
Available from Underwriters Laboratories (UL), 2600 N.W. Lake Rd., Camas, WA 98607-8542, http://www.ul.com.
D2656 − 20
TABLE 2 Partial Discharge (Corona) Extinction Voltage
Requirements
Minimum Level, kV
Rated Circuit Voltage
Grounded Ungrounded
Phase to Phase, V
Neutral Neutral
Shielded
A
2 001 to 5 000 4 5
A
2 001 to 5 000 4 5
5 001 to 8 000 6 8
5 001 to 8 000 6 8
8 001 to 15 000 11 15
8 001 to 15 000 11 15
15 001 to 25 000 19 26
15 001 to 25 000 19 26
25 001 to 28 000 21
25 001 to 28 000 21
28 001 to 35 000 26
28 001 to 35 000 26
A
Unless otherwise indicated the cable shall be rated grounded neutral.
5.4 Insula
...