All persons performing electrical work at construction
projects shall be certified by the State Fire Marshall or by the Department of
Mines.
32.1. General Requirements.
(a) All electrical work, installation, and
wire capacities shall be in accordance with the pertinent provisions of the
National Electrical Code, NFPA 70-1971; ANSI C1-1971 (Rev. of C1-1968)
unless otherwise provided by these regulations.
(b) Applicability. These regulations apply
only to electrical installations and used on the job site, both temporary and
permanent. For power distribution and transmission lines, refer to subpart V of
OSHA Safety and Health Regulations for Construction.
(c) Protection of employees.
(1) No employer shall permit an employee to
work in such proximity to any part of an electric power circuit that he may
contact the same in the course of his work unless the employee is protected
against electric shock by deenergizing the circuit and grounding it or
by guarding it by effective insulation or other means. In work areas where the
exact location of underground electric power lines is unknown, workmen using
jackhammers, bars, or other hand tools which may contact a line shall be
provided with insulated protective gloves.
(2) Before work is begun, the employer shall
ascertain by inquiry or direct observation, or by instruments, whether any part
of an electric power circuit, exposed, or concealed, is so located that the
performance of the work may bring any person, tool, or machine into physical or
electrical contact therewith. The employer shall post and maintain
proper warning signs where such a circuit exists. He shall advise his employees
of the location of such lines, the hazards involved and the protective measures
to be taken.
(d)
Passageways and open spaces. Suitable barriers or other means shall be
provided to ensure that work space for electrical equipment will not be
used as a passageway during periods when energized parts of electrical
equipment are used.
(e) Work space
around equipment. Sufficient space shall be provided and maintained in
the area of electrical equipment to permit ready and safe operation and
maintenance of such equipment. When parts are exposed, the minimum
clearance for the work space shall be not less than six and one-quarter (6 1/4)
feet high, nor less than a radius of three (3) feet wide, and there shall be
clearance sufficient to permit at least ninety degrees (90)
opening of all doors or hinged panels. All working clearances shall be
maintained in accordance with article 110-16, National Electrical Code,
NFPA 70-1971; ANSI CI-1971 (Rev. of CI-1968).
(f) Load ratings. In existing
installation no changes in circuit protection shall be made to increase
the load in excess of load rating of the circuit wiring, as specified in
National Electrical Code, NFPA 70-1971; ANSI CI-1971 (Rev. of CI-1968) (Article
310.)
(g) Lockout and tagging of
circuits.
(1) Equipment or circuits that are
deenergized shall be rendered inoperative and have tags attached at all points
where such equipment or circuits can be energized.
(2) Tags shall be placed to identify
plainly the equipment or circuits being worked on.
(h) Ground-fault protection.
(1) General. Notwithstanding any other
provision of this part, the requirements in Section 210-7 of the 1971
National Electrical Code (NFPA 70-1971; ANSI CI-1971), that all fifteen (15-)
and twenty (20-) amphere receptacle outlets on single-phase circuits
for construction sites have approved ground-fault circuit protection for
personnel does not apply. In lieu thereof, the employer shall use either
ground-fault circuit interrupters or an assured equipment grounding
conductor program to protect employees on construction sites. These
requirements are in addition to any other requirements for equipment
grounding conductors.
(2)
Ground-fault circuit interrupters. All one hundred twenty (120) volt,
single-phase, fifteen (15-) and twenty (20-) amphere receptacle outlets on
construction sites, which are not a part of the permanent wiring of the
building or structure and which are in use by employees, shall have approved
ground-fault circuit interrupters for personnel protection. Receptacles on a
two (2-) wire, single-phase portable or vehicle-mounted generator rated not
more than five (5)kw, where the circuit conductors of the generator are
insulated from the generator frame and all other grounded surfaces, need not be
protected with ground-fault circuit interrupters.
(3) Assured equipment grounding conductor
program. The employer shall establish and implement an assured
equipment grounding conductor program on construction sites covering all cord
sets, receptacles which are not a part of the permanent wiring of the building
or structure, and equipment connected by cord and plug which are
available for use or used by employees. This program shall comply with the
following minimum requirements:
(i) A
written description of the program, including the specific procedures
adopted by the employer, shall be available at the job site for
inspection and copying by the Director and any affected employee.
(ii) The employer shall designate one (1) or
more competent persons to implement the program.
(iii) Each cord set, attachment cap,
plug and receptacle of cord sets, and any equipment connected by cord
and plug except cord sets and receptacles which are fixed and not exposed to
damage, shall be visually inspected before each day's use for external defects,
such as deformed or missing pins or insulation damage, and for indication of
possible internal damage. Equipment found damaged or defective may not be used
until repaired.
(iv) The following
tests shall be performed on all cord sets, receptacles which are not a part of
the permanent wiring of the building or structure, and cord and plug-connected
equipment required to be grounded:
(a) All
equipment grounding conductors shall be tested for continuity and shall
be electrically continuous.
(b)
Each receptacle and attachment cap or plug shall be tested for correct
attachment of the equipment grounding conductor. The equipment grounding
conductor shall be connected to its proper terminal.
(v) All required tests shall be
performed:
(a) Before first use;
(b) Before equipment is returned to service
following any repairs;
(c) Before
equipment is used after any incident which can be reasonably suspected
to have caused damage (for example, when a cord set is run over); and
(d) At intervals not to exceed three (3)
months, except that cord sets and receptacles which are fixed and not
exposed to damage shall be tested at intervals not exceeding six (6)
months.
(vi) The
employer may not make available or permit the use by employees of any equipment
which has not met the requirements of this section.
(vii) Tests performed as required in this
paragraph shall be recorded in a book approved by the Department of Mines. This
test record shall identify each receptacle, cord set, and cord-and
plug-connected equipment that passed the test, and shall indicate the
last date it was tested or the interval for which it was tested. This record
shall be kept by means of logs, color coding, or other effective means, and
shall be maintained until replaced by a more current record. The record shall
be made available on the job site for inspection by any affected
employee.
32.2. Grounding and bonding.
(a) Portable and/or cord
plugconnected equipment.
(1) The
noncurrent-carrying metal parts of portable and/or plug-connected equipment
shall be grounded.
(2) Portable
tools and appliances protected by an approved system of double insulation, or
its equivalent, need not be grounded. Where such an approved system is
employed, the equipment shall be distinctively marked.
(b) Fixed equipment. Exposed
noncurrent-carrying metal parts of fixed electrical equipment,
including motors, generators, frames and tracks of electrically operated
cranes, electrically driven machinery, etc., shall be grounded.
(c) Effective grounding. The path from
circuits, equipment, structures, and conduit or enclosures to ground shall be
permanent and continuous; have ample carrying capacity to conduct
safely the current liable to be imposed on it; and have impedance
sufficiently low to limit the potential above ground and to result in
the operation of the overcurrent devices in the circuit.
(d) Ground resistance. Driven rod electrodes
shall, where practicable, have a resistance to ground not to exceed twenty-five
(25) ohms where the resistance is not as low as 25 ohms, two (2) or more
electrodes connected in parallel shall be used.
(e) Testing of grounds. Grounding circuits
shall be checked to ensure that the circuit between the ground and the grounded
power conductor has a resistance which is low enough to permit sufficient
current to flow to cause the fuse or circuit breaker to interrupt the
current.
(f) Extension cords.
Extension cords used with portable electric tools and appliances shall be of
the three (3)-wire type.
(g)
Bonding. Conductors used for bonding and grounding stationary and movable
equipment shall be of ample size to carry the anticipated current.
When attaching bonding and grounding clamps or
clips, a secure and positive metal-to-metal contact shall be made. Such
attachments shall be made before closures are opened and material movements are
started and shall not be broken until after material movements are stopped and
closures are made.
(h)
Temporary wiring. All temporary wiring shall be effectively grounded in
accordance with the National Electrical Code, NFPA 70-1971; ANSI
CI-1971 (Rev. of CI-1968), Articles 305 and 310.
(i) Construction site. Precautions shall be
taken to make any necessary open wiring inaccessible to unauthorized
personnel.
(j) Temporary lighting.
Temporary lights shall be equipped with guards to prevent accidental contact
with the bulb, except that guards are not required when the construction of the
reflector is such that the bulb is deeply recessed.
Temporary lights shall be equipped with heavy duty electric
cords with connections and insulation maintained in safe
condition. Temporary lights shall not be suspended by their electric
cords unless cords and lights are designed for this means of suspension.
Splices shall have insulation equal to that of the cable.
Working spaces, walkways, and similar locations
shall be kept clear of cords so as not to create a hazard to employees.
Portable electric lighting used in moist and/or other
hazardous locations, as for example, drums, tanks, and vessels shall be
operated at a maximum of twelve (12) volts.
32.3. Equipment installation and
maintenance.
(a) Flexible cable and
cords.
(1) Receptacles for attachment plugs
shall be of approved, concealed contact type with a contact for extending
ground continuity and shall be so designed and constructed that the
plug may be pulled out without leaving any live parts exposed to
accidental contact.
(2) Where
different voltages, frequencies, or types of current (a.c. or d.c.) are to be
supplied by portable cords, receptacles shall be of such design that
attachment plugs used on such circuits are not
interchangeable.
(3)
Attachment plugs or other connectors supplying equipment at more than three
hundred (300) volts shall be of the skirted type or otherwise so
designed that arcs will be confined.
(4) Attachment plugs for use in work areas
shall be so constructed that they will endure rough use and be equipped with a
suitable cord grip to prevent strain on the terminal screws.
(5) Flexible cord shall be used only in
continuous lengths without splice, except suitable molded or vulcanized splices
may be used where properly made, and the insulation shall be equal to the cable
being spliced and wire connections soldered.
(6) Trailing cables shall be
protected from damage.
(7)
Splices in trailing cable shall be mechanically strong components and
insulated to retain the mechanical and dielectric strength of the
original cable.
(8) Cable passing
through work areas shall be covered or elevated to protect it from damage which
would create a hazard to employees.
(9) Handlamps of the portable type shall be
of the molded composition or other type approved for the purpose.
Brass-shell, paper-lined lampholders shall not be used. Handlamps shall
be equipped with a handle and a substantial guard over the bulb and attached to
the lampholder or the handle.
(10)
Worn or frayed electric cables shall not be used.
(11) Extension cords shall be protected
against accidental damage as may be caused by traffic, sharp corners,
or projections and pinching in doors or elsewhere.
(12) Extension cords shall not be fastened
with staples, hung from nails, or suspended by wire.
(b) Overcurrent protection.
(1) Overcurrent protection shall be provided
by fuses or circuit breakers for each feeder and branch circuit, and shall be
based on the current-carrying capacity of the conductors supplied and the power
load being used.
(2) No overcurrent
devices shall be placed in any permanently grounded conductor, except
where the overcurrent device simultaneously opens all conductors of the circuit
or for motor running protection.
(3) When fuses are installed or removed with
one (1) or both terminals energized, special tools insulated for the
voltage shall be used.
(c) Switches, circuit breakers, and
disconnecting means.
(1) Each disconnecting
means for motors and appliances, and each service feeder or branch circuit at
the point where it originates, shall be legibly marked to indicate its
purpose unless located and arranged so the purpose is evident.
(2) Disconnecting means shall be located or
shielded so that employees will not be injured.
(3) Boxes for disconnecting means shall be
securely and rigidly fastened to the surface upon which they are mounted and
fitted with covers.
(4) Boxes and
disconnecting means installed in damp or wet locations shall be waterproof to
the extent that water does not enter or accumulate.
(d) Transformers.
(1) Energized transformers and other related
electrically energized equipment over one hundred fifty (150) volts to ground
shall be protected so as to prevent accidental contact with any person.
Protection shall be provided by individual integrated housing or by an
enclosure, such as an electrical substation fence, which accommodates a
group of such equipment. Metallic enclosures shall be grounded.
(2) Access to energized equipment
covered by subparagraph (1) of this paragraph shall be secured by lock or other
fasteners requiring the use of tools to open them.
(3) Signs indicating danger and prohibiting
unauthorized access shall be conspicuously displayed on the housing or
other enclosure around the equipment.
(4) Transformers mounted on utility poles at
a height of more than twelve (12) feet from the ground are exempt from the
requirements of this paragraph.
(e) Welding and cutting equipment. Welding
and cutting equipment shall meet the requirements specified in Sections 20 and
31 of these regulations.
32.4. Battery rooms and battery charging.
(a) General requirements.
(1) Batteries of the nonseal type shall be
located in enclosures with outside vents or in well ventilated rooms, so
arranged as to prevent the escape of fumes, gases, or electrolyte spray into
other areas.
(2) Ventilation shall
be provided to ensure diffusion to the gases from the battery to prevent the
accumulation of an explosive mixture.
(3) Racks and trays shall be substantial and
treated to be resistant to the electrolyte.
(4) Floors shall be of acid resistant
construction or be protected from acid accumulations.
(5) Face shields, aprons, and rubber gloves
shall be provided for workmen handling acids or batteries.
(6) Facilities for quick drenching of the
eyes and body shall be provided within twenty-five (25) feet of the work area
for emergency use.
(7) Facilities
shall be provided for flushing and neutralizing spilled electrolyte,
for fire protection, for protecting charging apparatus from damage by
trucks, and for adequate ventilation for dispersal of fumes from gassing
batteries.
(b) Charging.
(1) Battery charging installations shall be
located in areas designated for that purpose.
(2) When charging batteries, the vent caps
shall be kept in place to avoid electrolyte spray. Care shall be taken
to assure that vent caps are functioning.
32.5. Hazardous locations.
(a) General. For the purpose of this section,
hazardous locations are defined as follows:
(1) Class 1 Locations: Class 1 Locations are
those in which flammable gases or vapors are or may be present in quantities
sufficient to produce explosive or ignitable mixtures.
(2) Class 2 Locations: Class 2 Locations are
those which are hazardous because of the presence of combustible
dust.
(3) Class 3 Locations: Class
3 Locations are those which are hazardous because of the presence of
easily ignitable fibers or flyings, but in which such fibers or flyings are not
likely to be in suspension in air in quantities sufficient to produce ignitable
mixtures.
(4) See the National
Electrical Code, NFPA 70-1971; ANSI CI-1971 (Rev. of CI-1968) for further
definitions of Divisions 1 and 2 for each class.
(b) All components and utilization equipment
used in a hazardous location shall be chosen from among those listed by a
nationally recognized testing laboratory, such as Underwriters
Laboratories, Inc., or Factory Mutual Engineering Corporation, except
custom-made components and utilization equipment.
(c) Equipment approved for a specific
hazardous location shall not be installed or intermixed with equipment approved
for another specific hazardous location.
(d) Employer shall ensure that all wiring
components and utilization equipment are maintained as vapor, dust, or fiber
tight as contemplated by their approvals. There shall be no loose or missing
screws, gaskets, threaded connections, or other impairments to this
tight condition.
32.6.
Definitions applicable to this subpart.
(a) The definition of "Approved" as set forth
in this section shall apply.
(b)
"Bonding Jumper" a conductor to assure the required electrical conductivity
between metal parts required to be electrically connected.
(c) "Branch Circuits" that portion of a
wiring system extending beyond the final overcurrent device protecting
the circuit. (A device not approved for branch circuit protection, such
as thermal cutout or motor overload protective device, is not considered as the
overcurrent device protecting the circuit.)
(d) "Circuit Breaker" a device
designed to open and close a circuit by manual means, an to open the
circuit automatically on a predetermined overload of current, without injury to
itself when properly applied within its rating.
(e) "Exposed" (as applied to live parts)
means that a live part can be inadvertently touched or approached nearer than a
safe distance by a person. This term applies to parts not suitably guarded,
isolated, or insulated.
(f)
"Ground" a conducting connection, whether intentional or accidental, between an
electrical circuit or equipment and earth, or to some conducting body which
serves in place of the earth.
(g)
"Grounded" connected to earth or to some conducting body which serves in place
of the earth.
(h) "Hazard" is
considered to include casualty, fire, and shock when applicable.
(i) "Isolated" means not readily
accessible to person unless special means of access are used.
(j) "Raceway" any channel for loosely holding
wires or cable in interior work which is designed expressly and used solely for
this purpose. Raceways may be of metal, wood, or insulating material, and the
term includes wood and metal moldings consisting of a backing and capping, and
also metal ducts into which wires are to be pulled.
(k) "Shock Hazard" considered to exist at an
accessible part in a circuit between the part and ground, or other accessible
parts if the potential is more than forty-two and fourtenths (42.4)
volts peak and the current through a one thousand five hundred (1,500)-ohm load
is more than five (5) milliampheres.
(l) "Weatherproof" so constructed or
protected that exposure to the weather shall not interfere with successful
operation.