ASTM F712  Standard Test Methods and Specifications for Electrically Insulating Plastic Guard Equipment for Protection of Workers
ASTM F712工人防护用电绝缘塑料防护设备的标准试验方法和规范
All three tests may be used for product design qualification.
This specification covers the minimum electrical, chemical, and physical properties designated by the manufacturer and the detailed procedures by which such properties are to be determined. The purchaser has the option to perform or have performed any of these tests and may reject equipment that fails to meet the standard criteria. Claims concerning failure to meet the specification are subject to verification by the manufacturer.
Plastic guard equipment is used for protection against accidental brush contact by the worker. A margin of safety shall be provided between the maximum voltage at which they are used and the proof-test voltage at which they are tested. This relationship is shown in Table 1 and Table 2. The equipment is designed only for phase-to-ground or covered phase-to-covered-phase exposure.
Note 1—Rubber insulating equipment is realistically limited to Class 4 material in the design specification standards. Plastic guard equipment has been designed to go beyond these voltages and provide a satisfactory degree of worker protection. Major differences exist in use criteria between the rubber and the plastic guard equipment. Each glove, sleeve, or other article of rubber insulating equipment has a given safety factor for the phase to phase voltage on which it may be used and the class or proof voltage at which it is tested. Plastic guard equipment, however, is designed to provide a satisfactory safety factor only when used in a phase-to-ground exposure. If exposure is phase-to-phase, then a satisfactory safety factor is only provided if the exposure is covered-phase-to-covered-phase.
Work practices vary from user to user, dependent upon many factors. These may include, but are not limited to, operating system voltages, construction design, work procedure techniques, weather conditions, etc. Therefore, except for the restrictions set forth in this specification because of design limitations, the use and maintenance of this equipment is beyond the scope of this specification.
It is common practice and the responsibility of the user of this type of protective equipment to prepare complete instructions and regulations to govern in detail the correct and safe use of such equipment.
1. Scope
1.1 These test methods cover three electrical tests on plastic guards and assembled guard systems. They are:
1.1.1 Method A—Withstand voltage proof test,
1.1.2 Method B—Flashover voltage, and
1.1.3 Method C—Leakage current.
1.1.4 This specification covers plastic guard equipment and guard systems used by workers for temporary insulation on electric power circuits.
1.1.5 Plastic guard equipment covered by this specification is rated for momentary, or brush contact only. Maximum-use voltages are covered in Table 1 and Table 2.
1.2 These test methods cover, but are not limited to, the following typical guards:
1.2.1 Conductor Guards and Connecting Covers as follows:
1.2.1.1 Line guards,
1.2.1.2 Line guard connectors,
1.2.1.3 Insulator covers,
1.2.1.4 Dead-end covers,
1.2.1.5 Bus guards, and
1.2.1.6 Bus “T” guards.
1.2.2 Structure and Apparatus Covers as follows:
1.2.2.1 Pole guards,
1.2.2.2 Ridge pin covers,
1.2.2.3 Switch blade covers,
1.2.2.4 Arm guards,
1.2.2.5 Cutout covers,
1.2.2.6 Structural barriers, and
1.2.2.7 Cross arm guard.
1.3 It is common practice for the user of this equipment to prepare instructions for the correct use and maintenance.
1.4 The use and maintenance of this equipment is beyond the scope of these test methods.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

2. Referenced Documents (purchase separately)
ASTM Standards
D149 Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies
D256 Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics
D570 Test Method for Water Absorption of Plastics
IEEE Standard
IEEE978 Guide for In-Service Maintenance and Electrical Testing for Live-Line Tools
ANSI Standard
C39.5 Safety Requirements for Electrical and Electronic Measuring and Controlling Instrumentation
UL Standard
94 Tests for Flammability of Plastic Materials for Parts in Devices and Appliances
Index Terms
electrical protective equipment; electrically insulating plastic guard equipment; plastic guard equipment;