Current through Register 2024 Notice Reg. No. 38, September 20, 2024
(a) Except as provided herein, the Bureau of
Mines Mandatory Electricity Standards published July 31, 1969, February 25,
1970 and December 8, 1970 are adopted as part of these orders and read as
follows:
EXCEPTION: In no case shall the minimum requirements be
less than those established in the Electrical Safety Orders, T-8, CAC and Part
3, T-24, CAC.
GENERAL
(1) (12-1) Circuits shall be protected
against excessive overload by fuses or circuits breakers of the correct type
and capacity.
(2) (12-2) Electric
equipment and circuits shall be provided wit switches or other controls. Such
switches or controls shall be of approved design and construction and shall be
properly installed.
(3) (12-3)
Individual overload protection and short circuit protection shall be provided
for the trailing cables of mobile equipment.
(4) (12-7) Trailing cables and power-cable
connections to junction boxes shall not be made or broken while
energized.
(5) (12-11)
High-potential transmission cables shall be covered, insulated, or placed to
prevent contact with low-potential circuits.
(6) (12-14) Shovel trailing cables shall not
be moved with the shovel dipper unless cable slings or sleds are
used.
(7) (12-16) Electrical
equipment shall be deenergized before work is done on such equipment. Switches
shall be locked out or other measures taken which shall prevent the equipment
from being energized without the knowledge of the individuals working on it.
Such locks, or preventative devices shall be removed only by the persons who
installed them or by authorized personnel.
(8) (12-17) Power circuits shall be
deenergized before work is done on such circuits unless hotline tools are used.
Suitable warning signs shall be posted by the individuals who are to do the
work. Switches shall be locked out or other measures taken which shall prevent
the power circuits from being energized without the knowledge of the
individuals working on them. Such locks, signs, or preventative devices shall
be removed only by the person who installed them or by authorized
personnel.
(9) (12-18) All
switches, automatic cutouts, or other control devices shall be located or
marked as to clearly indicate the equipment controlled by them, and switches
(excepting magnetic switches) shall indicate whether they are open or
closed.
(10) (12-20) Dry wooden
platforms, insulating mats, or other electrically-nonconductive material shall
be kept in place at all switchboards and power-control switches where shock
hazards exist. However, metal plates on which a person normally would stand and
which are kept at the same potential as the grounded, metal,
noncurrent-carrying parts of the power switches to be operated may be
used.
(11) (12-21) Suitable danger
signs shall be posted at all major electrical installations.
(12) (12-23) Electrical connections and
resistor grids that are difficult or impractical to insulate shall be guarded,
unless protection is provided by location.
(13) (12-25) All metal enclosing or encasing
electrical circuits shall be grounded or provided with equivalent protection.
This requirement does not apply to battery-operated equipment.
(14) (12-26) Metal fencing and metal
buildings enclosing transformers and switchgear shall be grounded.
(15) (12-27) Frame grounding or equivalent
protection shall be provided for mobile equipment powered through trailing
cables.
(16) (12-28) Continuity and
resistance of grounding systems shall be tested immediately after
installation.
(17) (12-30) When a
potentially dangerous condition is found it shall be corrected before equipment
or wiring is energized.
(18)
(12-33) Hand-held electric tools shall not be operated at high potential
voltages.
(19) (12-36) Fuses shall
not be removed or replaced by hand in an energized circuit, and they shall not
otherwise be removed or replaced in an energized circuit unless equipment and
techniques especially designed to prevent electric shock are provided and used
for such purpose.
(20) (12-37) Fuse
tongs or hot line tools shall be used when fuses are removed or replaced in
high-potential circuits.
(21)
(12-40) Operating controls shall be installed so that they can be operated
without danger of contact with energized conductors.
(22) (12-41) Switches and starting boxes
shall be of safe design and capacity.
(23) (12-45) Overhead high-potential
powerlines lines shall be installed as specified by the Electrical Safety
Orders and Part 3, T-24, CAC.
(24)
(12-47) Guy wires of poles supporting high-potential conductors shall be
equipped with insulators installed near the pole end.
(25) (12-48) Telegraph, telephone, or signal
wires shall not be installed on the same crossarm with power conductors. When
carried on poles supporting powerlines, they shall be installed as specified by
the Electrical Safety Orders and Part 3, T-24, CAC.
(26) (4-10) Power wires and cables shall be
adequately insulated. Flexible cords and cables shall not be used as a
substitute for fixed wiring and shall be adequately protected when subject to
physical damage.
(27) (4-11)
Abandoned electrical circuits shall be de-energized and isolated so that they
cannot become energized inadvertently.
SURFACE ONLY
(28) (12-65) Powerlines, including trolley
wires, and telephone circuits shall be protected against short circuits and
lightning.
(29) (12-66) Where
metallic tools or equipment can come in contact with trolley wires or bare
powerlines, the lines shall be guarded or deenergized.
(30) (12-67) Transformers shall be totally
enclosed, located on poles or shall be enclosed in compliance with the
Electrical Safety Orders.
(31)
(12-68) Transformer enclosures shall be kept locked against unauthorized
entry.
(32) Provisions for
preventing accidents due to overhead high-voltage lines shall be in conformance
with the High-Voltage Electrical Safety Orders, Article 86, which reads:
Article 86. Provisions for Preventing Accidents
Due to Proximity of Overhead Lines
2946. Provisions for Preventing Accidents Due to
Proximity to Overhead Lines.
(a)
General. No person, firm, or corporation, or agent of same, shall require or
permit any employee to perform any function in proximity to energize
high-voltage lines; to enter upon any land, building, or other premises and
thereto engage in any excavation, demolition, construction, repair, or other
operation; or to erect, install, operate, or store in or upon such premises any
tools, machinery, equipment, materials, or structures (including scaffolding,
house moving, well drilling, pile driving, or hoisting equipment) unless and
until danger from accidental contact with said high-voltage lines has been
effectively guarded against.
(b)
Clearances or Safeguards Required. Except where electrical distribution and
transmission lines have been deenergized and visibly grounded or effective
barriers have been erected to prevent physical and arcing contacts with the
high-voltage lines, the following provisions shall be met:
(1) Over Lines. The operation, erection, or
handling of tools, machinery, apparatus, supplies, or materials, or any part
thereof, over energized high-voltage lines shall be prohibited.
(2) Equipment and Materials in Use. The
operation, erection, or handling of tools, machinery equipment, apparatus,
materials, or supplies, or any part thereof within the minimum clearances from
energized lines set forth in Table X shall be prohibited.
|
Table X |
|
Required Clearances from
Overhead High-Voltage Lines |
|
|
| Nominal Voltage
(Phase to Phase) | Minimum Required
Clearance (Feet) |
| | .......................... 750-
50,000 | ..........................10 | |
|
| Over | ..........................
50,000- 75,000 | ..........................11 | |
|
| Over | ..........................
75,000- 125,000 | ..........................13 | |
|
| Over | ..........................125,000-
175,000 | ..........................15 | |
|
| Over | ..........................175,000-
250,000 | ..........................17 | |
|
| Over | ..........................250,000-
370,000 | ..........................21 | |
|
| Over | ..........................370,000-
550,000 | ..........................27 | |
|
| Over | ..........................550,000-1,000,000 | ..........................42 | |
(3) Transportation or Transit. The
transportation or transit of any tool, machinery, equipment, or apparatus, or
the moving of any house or other building in proximity to overhead high-voltage
lines shall be expressly prohibited if at any time during such transportation
or transit such tool, machinery, equipment, apparatus, or building or any part
thereof, can come closer to high-voltage lines than the minimum clearances set
forth in Table Y.
Except where the boom of boom-type equipment is lowered
and no load is imposed thereon, the equipment in transit shall conform to the
minimum required clearances set forth in Table X.
|
Table Y |
|
Required Clearances from
Energized High-Voltage Conductors (While in Transit) |
|
|
| Nominal Voltage
(Phase to Phase) | Minimum Required
Clearance (Feet) |
| | .......................... 750-
50,000 | ..........................6 | |
|
| Over | ..........................
50,000- 345,000 | ..........................10 | |
|
| Over | ..........................345,000-
750,000 | ..........................16 | |
|
| Over | ..........................750,000-1,000,000 | ..........................20 | |
(4) Storage. The storage of tools, machinery,
equipment, supplies, materials, or apparatus under, by, or near energized
high-voltage lines is hereby expressly prohibited if at any time during such
handling or other manipulation it is possible to bring such tools, machinery,
equipment, supplies, materials, or apparatus, or any part thereof, within the
minimum required clearances from high-voltage lines as set forth in Table
X.
(c) The specified
clearance shall not be reduced by movement due to any strains impressed (by
attachments or otherwise) upon the structures supporting the high-voltage line
or upon any equipment, fixtures, or attachments thereon.
(d) Insulated cage-type boom guards, boom
stops, insulating links, or proximity warning devices may be used on cranes,
but the use of such devices shall not alter the required clearances set forth
in Table X.
(e) Any overhead
conductor shall be considered to be energized unless and until the person
owning or operating such line verifies that the line is not energized, and the
line is visibly grounded at the work site.
2947. Warning Signs Required. The owner, agent, or
employer responsible for the operations of equipment shall post and maintain in
plain view of the operator and driver on each crane, derrick, power shovel,
drilling rig, hay loader, hay stacker, pile driver, or similar apparatus, a
durable warning sign legible at 12 feet reading:
"UNLAWFUL TO OPERATE THIS EQUIPMENT WITHIN 10 FEET OF
HIGH-VOLTAGE LINES OF 50,000 VOLTS OR LESS."
In addition to the above wording, the following
statement in small lettering shall be provided on the warning sign: "For
Minimum Clearances Of High-Voltage Lines In Excess of 50,000 Volts. See Article
86, Title 8, High-Voltage Electrical Safety Orders."
2948. Notification to the Operators of
High-Voltage Lines and Responsibility for Safeguards.
When any operations are to be performed, tools, or
materials handled, or equipment is to be moved or operated within the specified
clearances of any energized high-voltage lines, the person or persons
responsible for the work to be done shall promptly notify the operator of the
high-voltage line of the work to be performed and shall be responsible for the
completion of the safety measures as required by Order 2946(b) before
proceeding with any work which would impair the aforesaid clearance.
2949. Special Exemptions.
The provisions of the foregoing Orders 2946 through
2948 shall not apply to the construction, reconstruction, maintenance, or
operation of any energized high-voltage overhead lines or their supporting
structure or appurtenances by qualified electrical workers, nor to work
performed in proximity to high-voltage lines by qualified persons using
approved equipment and work procedures.
UNDERGROUND ONLY
(33) (12-80) Trolley wires and bare power
conductors shall be guarded at man-trip loading and unloading points, and at
shaft stations. Open unguarded trolley wires shall be placed not less than 9
feet above the track, or not less than 6 inches outside of the rail and not
less than 7 feet above the rail.
(34) (12-82) Powerlines shall be well
separated or insulated from waterlines, telephone lines, and air
lines.
(35) (12-85) Transformer
stations shall be enclosed to prevent persons from unintentionally or
inadvertently contacting energized parts.
1.
Repealer of subsection (a)(32) and new subsection (a)(32) filed 7-27-73,
effective thirtieth day thereafter (Register 73, No. 30).
2.
Editorial correction of subsection (a)(11) (Register 97, No.
25).
Note: Authority cited: Section
6500, Labor
Code.
