[Code of Federal Regulations]
[Title 29, Volume 5]
[Revised as of January 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1910.137]
[Page 446-449]
TITLE 29--LABOR
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT
OF LABOR
PART 1910_OCCUPATIONAL SAFETY AND HEALTH STANDARDS--Table of Contents
Subpart I_Personal Protective Equipment
Sec. 1910.137 Electrical protective equipment.
(a) Design requirements. Insulating blankets, matting, covers, line
hose, gloves, and sleeves made of rubber shall meet the following
requirements:
(1) Manufacture and marking. (i) Blankets, gloves, and sleeves shall
be produced by a seamless process.
(ii) Each item shall be clearly marked as follows:
(A) Class 0 equipment shall be marked Class 0.
(B) Class 1 equipment shall be marked Class 1.
(C) Class 2 equipment shall be marked Class 2.
(D) Class 3 equipment shall be marked Class 3.
(E) Class 4 equipment shall be marked Class 4.
(F) Non-ozone-resistant equipment other than matting shall be marked
Type I.
(G) Ozone-resistant equipment other than matting shall be marked
Type II.
(H) Other relevant markings, such as the manufacturer's
identification and the size of the equipment, may also be provided.
(iii) Markings shall be nonconducting and shall be applied in such a
manner as not to impair the insulating qualities of the equipment.
(iv) Markings on gloves shall be confined to the cuff portion of the
glove.
(2) Electrical requirements. (i) Equipment shall be capable of
withstanding the a-c proof-test voltage specified in Table I-2 or the d-
c proof-test voltage specified in Table I-3.
(A) The proof test shall reliably indicate that the equipment can
withstand the voltage involved.
(B) The test voltage shall be applied continuously for 3 minutes for
equipment other than matting and shall be applied continuously for 1
minute for matting.
(C) Gloves shall also be capable of withstanding the a-c proof-test
voltage specified in Table I-2 after a 16-hour water soak. (See the note
following paragraph (a)(3)(ii)(B) of this section.)
(ii) When the a-c proof test is used on gloves, the 60-hertz proof-
test current may not exceed the values specified in Table I-2 at any
time during the test period.
(A) If the a-c proof test is made at a frequency other than 60
hertz, the permissible proof-test current shall be computed from the
direct ratio of the frequencies.
(B) For the test, gloves (right side out) shall be filled with tap
water and immersed in water to a depth that is in accordance with Table
I-4. Water shall be added to or removed from the glove, as necessary, so
that the water level is the same inside and outside the glove.
(C) After the 16-hour water soak specified in paragraph (a)(2)(i)(C)
of this section, the 60-hertz proof-test current may exceed the values
given in Table I-2 by not more than 2 milliamperes.
(iii) Equipment that has been subjected to a minimum breakdown
voltage test may not be used for electrical protection. (See the note
following paragraph (a)(3)(ii)(B) of this section.)
(iv) Material used for Type II insulating equipment shall be capable
of withstanding an ozone test, with no visible effects. The ozone test
shall reliably indicate that the material will resist ozone exposure in
actual use. Any visible signs of ozone deterioration of the material,
such as checking, cracking, breaks, or pitting, is evidence of failure
to meet the requirements for ozone-resistant material. (See the note
following paragraph (a)(3)(ii)(B) of this section.)
(3) Workmanship and finish. (i) Equipment shall be free of harmful
physical irregularities that can be detected by the tests or inspections
required under this section.
(ii) Surface irregularities that may be present on all rubber goods
because of imperfections on forms or molds or because of inherent
difficulties in the
[[Page 447]]
manufacturing process and that may appear as indentations,
protuberances, or imbedded foreign material are acceptable under the
following conditions:
(A) The indentation or protuberance blends into a smooth slope when
the material is stretched.
(B) Foreign material remains in place when the insulating material
is folded and stretches with the insulating material surrounding it.
Note: Rubber insulating equipment meeting the following national
consensus standards is deemed to be in compliance with paragraph (a) of
this section:
American Society for Testing and Materials (ASTM) D 120-87,
Specification for Rubber Insulating Gloves.
ASTM D 178-93 (or D 178-88) Specification for Rubber Insulating
Matting.
ASTM D 1048-93 (or D 1048-88a) Specification for Rubber Insulating
Blankets.
ASTM D 1049-93 (or D 1049-88) Specification for Rubber Insulating
Covers.
ASTM D 1050-90, Specification for Rubber Insulating Line Hose.
ASTM D 1051-87, Specification for Rubber Insulating Sleeves.
These standards contain specifications for conducting the various
tests required in paragraph (a) of this section. For example, the a-c
and d-c proof tests, the breakdown test, the water soak procedure, and
the ozone test mentioned in this paragraph are described in detail in
the ASTM standards.
(b) In-service care and use. (1) Electrical protective equipment
shall 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:
(i) Maximum use voltages shall conform to those listed in Table I-5.
(ii) Insulating equipment shall 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 shall be given an
air test, along with the inspection.
(iii) Insulating equipment with any of the following defects may not
be used:
(A) A hole, tear, puncture, or cut;
(B) Ozone cutting or ozone checking (the cutting action produced by
ozone on rubber under mechanical stress into a series of interlacing
cracks);
(C) An embedded foreign object;
(D) Any of the following texture changes: swelling, softening,
hardening, or becoming sticky or inelastic.
(E) Any other defect that damages the insulating properties.
(iv) Insulating equipment found to have other defects that might
affect its insulating properties shall be removed from service and
returned for testing under paragraphs (b)(2)(viii) and (b)(2)(ix) of
this section.
(v) Insulating equipment shall be cleaned as needed to remove
foreign substances.
(vi) Insulating equipment shall 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.
(vii) Protector gloves shall be worn over insulating gloves, except
as follows:
(A) Protector gloves need not be used with Class 0 gloves, under
limited-use conditions, where small equipment and parts manipulation
necessitate unusually high finger dexterity.
Note: Extra care is needed in the visual examination of the glove
and in the avoidance of handling sharp objects.
(B) Any other class of glove may be used for similar work without
protector gloves if the employer can demonstrate that the possibility of
physical damage to the gloves is small and if the class of glove is one
class higher than that required for the voltage involved. Insulating
gloves that have been used without protector gloves may not be used at a
higher voltage until they have been tested under the provisions of
paragraphs (b)(2)(viii) and (b)(2)(ix) of this section.
(viii) Electrical protective equipment shall be subjected to
periodic electrical tests. Test voltages and the maximum intervals
between tests shall be in accordance with Table I-5 and Table I-6.
(ix) The test method used under paragraphs (b)(2)(viii) and
(b)(2)(ix) of this section shall 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:
[[Page 448]]
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 479-93, Specification for In-Service Care of Insulating
Blankets.
ASTM F 496-93b Specification for In-Service Care of Insulating
Gloves and Sleeves.
(x) Insulating equipment failing to pass inspections or electrical
tests may not be used by employees, except as follows:
(A) Rubber insulating line hose may be used in shorter lengths with
the defective portion cut off.
(B) Rubber insulating blankets may be repaired using a compatible
patch that results in physical and electrical properties equal to those
of the blanket.
(C) Rubber insulating blankets may be salvaged by severing the
defective area from the undamaged portion of the blanket. The resulting
undamaged area may not be smaller than 22 inches by 22 inches (560 mm by
560 mm) for Class 1, 2, 3, and 4 blankets.
(D) Rubber insulating gloves and sleeves with minor physical
defects, such as small cuts, tears, or punctures, may be repaired by the
application of a compatible patch. Also, rubber insulating gloves and
sleeves with minor surface blemishes may be repaired with a compatible
liquid compound. The patched area shall have electrical and physical
properties equal to those of the surrounding material. Repairs to gloves
are permitted only in the area between the wrist and the reinforced edge
of the opening.
(xi) Repaired insulating equipment shall be retested before it may
be used by employees.
(xii) The employer shall certify that equipment has been tested in
accordance with the requirements of paragraphs (b)(2)(viii), (b)(2)(ix),
and (b)(2)(xi) of this section. The certification shall identify the
equipment that passed the test and the date it was tested.
Note: Marking of equipment and entering the results of the tests and
the dates of testing onto logs are two acceptable means of meeting this
requirement.
Table I-2--A-C Proof-Test Requirements
----------------------------------------------------------------------------------------------------------------
Maximum proof-test current, mA (gloves only)
Proof-test -----------------------------------------------
Class of equipment voltage 267-mm
rms V (10.5-in) 356-mm (14- 406-mm (16- 457-mm (18-
glove in) glove in) glove 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 I-3--D-C Proof-Test Requirements
------------------------------------------------------------------------
Proof-test
Class of equipment 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 I-4. See
ASTM D 1050-90 and ASTM D 1049-88 for further information on proof tests
for rubber insulating line hose and covers.
[[Page 449]]
Table I-4--Glove Tests--Water Level \1,2\
------------------------------------------------------------------------
AC proof test DC 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
------------------------------------------------------------------------
\1\ The 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.).
\2\ If atmospheric conditions make the specified clearances impractical,
the clearances may be increased by a maximum of 25 mm. (1 in.).
Table I-5--Rubber Insulating Equipment Voltage Requirements
----------------------------------------------------------------------------------------------------------------
Maximum use
Class of equipment voltage \1\ a- Retest voltage Retest voltage
c--rms \2\ a-c--rms \2\ d-c--avg
----------------------------------------------------------------------------------------------------------------
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
----------------------------------------------------------------------------------------------------------------
\1\ The 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 design
voltage 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:
(1) If there is no multiphase exposure in a system area and if the voltage exposure is limited to the phase-to-
ground potential, or
(2) If the electrical equipment and devices are insulated or isolated or both so that the multiphase exposure on
a grounded wye circuit is removed.
\2\ The proof-test voltage shall be applied continuously for at least 1 minute, but no more than 3 minutes.
Table I-6--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.\1\
Rubber insulating gloves............... Before first issue and every 6
months thereafter.\1\
Rubber insulating sleeves.............. Before first issue and every 12
months thereafter.\1\
------------------------------------------------------------------------
\1\ If the insulating equipment has been electrically tested but not
issued for service, it may not be placed into service unless it has
been electrically tested within the previous 12 months.
[59 FR 4435, Jan. 31, 1994; 59 FR 33662, June 30, 1994]