ASTM F968-93(1998)

Standard Specification for Electrically Insulating Plastic Guard Equipment for Protection of Workers

SCOPE
1.1 This specification covers plastic guard equipment and guard systems used by workers for temporary insulation on electric power circuits.
1.2 Plastic guard equipment covered by this specification is rated for momentary, or brush contact only. Maximum-use voltages are covered in Annex A1.
1.3 Typical guards covered include, but are not limited to, the following:
1.3.1 Conductor guards and connecting covers as follows:
1.3.1.1 Line guards,
1.3.1.2 Line guard connectors,
1.3.1.3 Insulator covers,
1.3.1.4 Dead end covers,
1.3.1.5 Bus guards, and
1.3.1.6 Bus "T" guards.
1.3.2 Structure and apparatus covers as follows:
1.3.2.1 Pole guards,
1.3.2.2 Ridge pin covers,
1.3.2.3 Switch-blade covers,
1.3.2.4 Arm guards,
1.3.2.5 Cutout covers, and
1.3.2.6 Cross arm guard.
1.4 The values stated in inch-pound units are to be regarded as the standard.

General Information

• Status: Historical
• Publication Date: 09-Sep-1998
• Technical Committee: F18 - Electrical Protective Equipment for Workers
• Drafting Committee: F18.25 - Insulating Cover-Up Equipment

Relations

• Replaced By: ASTM F968-93(2002) - Standard Specification for Electrically Insulating Plastic Guard Equipment for Protection of Workers
• Effective Date: 15-Jan-1993

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: F 968 – 93 (Reapproved 1998)
Standard Specification for
Electrically Insulating Plastic Guard Equipment for
Protection of Workers
This standard is issued under the fixed designation F 968; 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 F 712 Test Methods for Electrically Insulating Plastic
Guard Equipment for Protection of Workers
1.1 This specification covers plastic guard equipment and
2.2 IEEE Standard:
guard systems used by workers for temporary insulation on
978 Guide for In-Service Maintenance and Electrical Test-
electric power circuits.
ing for Live-Line Tools
1.2 Plastic guard equipment covered by this specification is
2.3 UL Standard:
rated for momentary, or brush contact only. Maximum-use
94 Tests for Flammability of Plastic Materials for Parts in
voltages are covered in Annex A1.
Devices and Appliances
1.3 Typical guards covered include, but are not limited to,
the following:
3. Terminology
1.3.1 Conductor guards and connecting covers as follows:
3.1 Definitions of Terms Specific to This Standard:
1.3.1.1 Line guards,
3.1.1 insulating plastic guards—devices for temporary in-
1.3.1.2 Line guard connectors,
stallation on structures or energized electric power circuits for
1.3.1.3 Insulator covers,
electrical protection of personnel or equipment, or both.
1.3.1.4 Dead end covers,
3.1.2 self extinguishing—relates to a property of a plastic
1.3.1.5 Bus guards, and
material compounded so as to cease combustion on removal of
1.3.1.6 Bus “T” guards.
the source that caused ignition.
1.3.2 Structure and apparatus covers as follows:
1.3.2.1 Pole guards,
4. Significance and Use
1.3.2.2 Ridge pin covers,
4.1 This specification covers the minimum electrical,
1.3.2.3 Switch-blade covers,
chemical, and physical properties designated by the manufac-
1.3.2.4 Arm guards,
turer and the detailed procedures by which such properties are
1.3.2.5 Cutout covers, and
to be determined. The purchaser has the option to perform or
1.3.2.6 Cross arm guard.
have performed any of these tests and may reject equipment
1.4 The values stated in inch-pound units are to be regarded
that fails to meet the standard criteria. Claims concerning
as the standard.
failure to meet the specification are subject to verification by
2. Referenced Documents the manufacturer.
4.2 Plastic guard equipment is used for protection against
2.1 ASTM Standards:
accidental brush contact by the worker. A margin of safety shall
D 149 Test Methods for Dielectric Breakdown Voltage and
be provided between the maximum voltage at which they are
Dielectric Strength of Solid Electrical Insulating Materials
2 used and the proof-test voltage at which they are tested. This
at Commercial Power Frequencies
relationship is shown in Table A1.1. The equipment is designed
D 150 Test Methods for AC Loss Characteristics and Per-
only for phase-to-ground or coveredphase-to-covered-phase
mittivity (Dielectric Constant) of Solid Electrical Insulat-
2 exposure.
ing Materials
D 256 Test Methods for Determining the Pendulum Impact
NOTE 1—Rubber insulating equipment is realistically limited to Class 4
Resistance of Notched Specimens of Plastics material in the design specification standards. Plastic guard equipment has
been designed to go beyond these voltages and provide a satisfactory
D 570 Test Method for Water Absorption of Plastics
degree of worker protection. Major differences exist in use criteria
between the rubber and the plastic guard equipment. Each glove, sleeve,
This specification is under the jurisdiction of ASTM Committee F-18 on
Electrical Protective Equipment for Workers and is the direct responsibility of
Subcommittee F18.25 on Insulating Cover-up Equipment. Annual Book of ASTM Standards, Vol 10.03.
Current edition approved Jan. 15, 1993. Published March 1993. Originally Available from the Institute of Electrical and Electronics Engineers, 345 E. 47th
published as F 968 – 85. Last previous edition D 968 – 90. St., New York, NY 10017.
2 6
Annual Book of ASTM Standards, Vol 10.01. Available from Underwriters Laboratories, 333 Pfingsten Rd., Northbrook, IL
Annual Book of ASTM Standards, Vol 08.01. 60062.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F 968
or other article of rubber insulating equipment has a given safety factor for 6.1.2-6.1.6 in a single product number. With that system, a typical order
the phase to phase voltage on which it may be used and the class or proof description is: 100 (Smith Manufacturing Co., Product No. XXXX) Line
voltage at which it is tested. Plastic guard equipment, however, is designed Guards, ASTM Specification F 968.
to provide a satisfactory safety factor only when used in a phase-to-ground
7. Materials
exposure. If exposure is phase-to-phase, then a satisfactory safety factor is
only provided if the exposure is covered-phase-to-covered-phase.
7.1 Principal construction of insulating body shells shall be
4.3 Work practices vary from user to user, dependent upon in accordance with the material requirements as follows:
many factors. These may include, but are not limited to, 7.1.1 Type I Guards—Minimum 1.5 ft·lbf/in. (80.06 J/m of
operating system voltages, construction design, work proce- notch) notched izod impact strength at − 20°F(−29°C); maxi-
dure techniques, weather conditions, etc. Therefore, except for mum water absorption 0.1 % by weight; minimum 380 V/mL
the restrictions set forth in this specification because of design (0.025 mm) dielectric strength.
limitations, the use and maintenance of this equipment is 7.1.2 Type II Guards—Minimum 1.0 ft·lbf/in. (53.4 J/m)
beyond the scope of this specification. notched izod impact strength at − 20°F(−29°C); maximum
4.4 It is common practice and the responsibility of the user water absorption 0.5 % by weight; minimum 320 V/mL (0.025
of this type of protective equipment to prepare complete mm) dielectric strength; 94 V-O flame retardancy.
instructions and regulations to govern in detail the correct and 7.1.3 Type III Guards—Minimum 3.0 ft·lbf/in. (160.1 J/m
safe use of such equipment. of notch) notched izod impact strength at − 20°F(−29°C);
maximum water absorption 0.09 % by weight; minimum 300
5. Classification
V/mL (0.025 mm) dielectric strength; 94 V-O flame retardancy.
5.1 Guards are furnished in three types of materials speci-
7.1.4 Material ratings for Notched Izod Impact Strength
fied in Section 6 and explained as follows:
shall be in accordance with Test Methods D 256, Method A.
5.1.1 Type I guards are constructed of plastic material
7.1.5 Material ratings for water absorption shall be in
having mechanical impact properties suitable for cold weather
accordance with Test Method D 570.
service.
7.1.6 Material ratings for dielectric strength shall be in
5.1.2 Type II guards have self-extinguishing plastic con-
accordance with Test Method D 149.
struction.
7.1.7 Material ratings for flame retardancy shall be in
5.1.3 Type III guards are constructed of self-extinguishing
accordance with UL Standard 94.
plastic material having mechanical impact properties suitable
7.2 Handles of Grade 1 Guards shall be reinforced plastic
for cold weather service.
and shall be capable of withstanding 100 kV at 60 Hz for each
5.2 Guards are furnished in three grades in accordance with
1 ft (300 mm) of length for 5 min without heating or tracking.
provisions for installation
...