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PDFWAC 296-307-38018

How must electrical protective devices be maintained and used?

(1) Electrical protective equipment must be maintained in a safe, reliable condition.
(2) The following specific requirements apply to insulating blankets, covers, line hose, gloves, and sleeves made of rubber:
(a) Maximum use voltages must meet the requirements in Table 4.
(b) Insulating equipment must be inspected for damage before each day's use and immediately following any incident that can reasonably be suspected of having caused damage. Insulating gloves must be given an air test, along with the inspection.
(c) Insulating equipment with any of the following defects must not be used:
(i) A hole, tear, puncture, or cut;
(ii) Ozone cutting or ozone checking (the cutting action produced by ozone on rubber under mechanical stress into a series of interlacing cracks);
(iii) An embedded foreign object;
(iv) Any of the following texture changes: Swelling, softening, hardening, or becoming sticky or inelastic;
(v) Any other defect that damages the insulating properties.
(d) Insulating equipment found to have other defects that might affect its insulating properties must be removed from service and returned for testing under (h) of this subsection.
(e) Insulating equipment must be cleaned as needed to remove foreign substances.
(f) Insulating equipment must be stored in such a location and in such a manner as to protect it from light, temperature extremes, excessive humidity, ozone, and other injurious substances and conditions.
(g) Protector gloves must be worn over insulating gloves.
(h) Electrical protective equipment must be subjected to periodic electrical tests. Test voltages and the maximum intervals between tests must be according to Table 4 and Table 5.
(i) The test method used must reliably indicate whether the insulating equipment can withstand the voltages involved.
Note:
Standard electrical test methods considered as meeting this requirement are given in the following national consensus standards:
 
• American Society for Testing and Materials (ASTM) D 120-87, Specification for Rubber Insulating Gloves.
 
• ASTM D 1048-93, Specification for Rubber Insulating Blankets.
 
• ASTM D 1049-93, Specification for Rubber Insulating Covers.
 
• ASTM D 1050-90, Specification for Rubber Insulating Line Hose.
 
• ASTM D 1051-87, Specification for Rubber Insulating Sleeves.
 
• ASTM F 478-92, Specification for In-Service Care of Insulating Line Hose and Covers.
 
• ASTM F 479-88a, Specification for In-Service Care of Insulating Blankets.
 
• ASTM F 496-93b, Specification for In-Service Care of Insulating Gloves and Sleeves.
(j) Insulating equipment that fails inspections or electrical tests must not be used by employees, except as follows:
(i) Rubber insulating line hose could be used in shorter lengths with the defective portion cut off.
(ii) Rubber insulating blankets could be repaired using a compatible patch that results in physical and electrical properties equal to those of the blanket.
(iii) Rubber insulating blankets could be salvaged by severing the defective area from the undamaged portion of the blanket. The resulting undamaged area must not be smaller than twenty-two inches by twenty-two inches (560 mm by 560 mm) for Class 1, 2, 3, and 4 blankets.
(k) Repaired insulating equipment must be retested before it may be used by employees.
(l) You must certify that equipment has been tested in accordance with the requirements of (h), (i), and (k) of this subsection. The certification must identify the equipment that passed the test and the date it was tested.
Note:
This requirement may be met by marking the equipment and entering the results of the tests and the dates of testing onto logs.
Table 1
A-C Proof-Test Requirements
Maximum proof-test current, mA (gloves only)
Class of
equipment
Proof-test
voltage rms V
267 mm
(10.5 in.) glove
356 mm
(14 in.) glove
406 mm
(16 in.) glove
457 mm
(18 in.) glove
0
5,000
 
8
12
14
16
1
10,000
 
 
14
16
18
2
20,000
 
 
16
18
20
3
30,000
 
 
18
20
22
4
40,000
 
 
 
22
24
Table 2
D-C Proof-Test Requirements
Class of Equipment
Proof-test voltage
0
20,000
1
40,000
2
50,000
3
60,000
4
70,000
Note: The d-c voltages listed in this table are not appropriate for proof testing rubber insulating line hose or covers. For this equipment, d-c proof-tests shall use a voltage high enough to indicate that the equipment can be safely used at the voltages listed in Table 3. See ASTM D 1050-90 and ASTM D 1049-88 for further information on proof tests for rubber insulating line hose and covers.
Table 3
Glove Tests-Water Level1, 2
 
A-C proof-test
D-C proof-test
Class of glove
mm.
in.
mm.
in.
0
38
1.5
38
1.5
1
38
1.5
51
2.0
2
64
2.5
76
3.0
3
89
3.5
102
4.0
4
127
5.0
153
6.0
1The water level is given as the clearance from the cuff of the glove to the water line, with a tolerance of 13 mm. (0.5 in.).
2If atmospheric conditions make the specified clearances impractical, the clearances may be increased by a maximum of 25 mm. (1 in.)
Table 4
Rubber Insulating Equipment
Voltage Requirements
Class of
equipment
Maximum use
voltage1 a-c-rms
Retest voltage2
a-c-rms
Retest voltage2
d-c-rms
0
1,000
 
5,000
 
20,000
1
7,500
 
10,000
 
40,000
2
17,000
 
20,000
 
50,000
3
26,500
 
30,000
 
60,000
4
36,000
 
40,000
 
70,000
Note: Rubber gloves shall only be used on voltages of 5000 volts phase to phase or less.
1The maximum use voltage is the a-c voltage (rms) classification of the protective equipment that designates the maximum nominal design/voltage of the energized system that may be safely worked. The nominal voltage design is equal to the phase-to-phase voltage on multiphase circuits. However, the phase-to-ground potential is considered to be the nominal design/voltage:
(a) If there is no multiphase exposure in a system area and if the voltage exposure is limited to the phase-to-ground potential, or
(b) If the electrical equipment and devices are insulated or isolated or both so that the multiphase exposure on a grounded wye circuit is removed.
2The proof-test voltage shall be applied continuously for at least one minute, but no more than three minutes.
Table 5
Rubber Insulating Equipment Test Intervals
Type of equipment
When to test
Rubber insulating line hose
Upon indication that insulating value is suspect
Rubber insulating covers
Upon indication that insulating value is suspect
Rubber insulating blankets
Before first issue and every 12 months thereafter
Rubber insulating gloves
Before first issue and every 6 months thereafter
Rubber insulating sleeves
Before first issue and every 12 months thereafter
(3) Where switches or fuses of more than 150 volts to ground are not guarded during ordinary operations, suitable insulating floors, mats or platforms must be provided on which the operator must stand while handling the switches.
[WSR 97-09-013, recodified as § 296-307-38018, filed 4/7/97, effective 4/7/97. Statutory Authority: RCW 49.17.040, [49.17.]050 and [49.17.]060. WSR 96-22-048, § 296-306A-38018, filed 10/31/96, effective 12/1/96.]
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