WAC 296-307-37009
What requirements apply to the disconnecting means for electric welders?
(1) A disconnecting means must be provided in the supply circuit for
each motor-generator arc welder, and for each AC transformer and DC rectifier
arc welder that is not equipped with a disconnect mounted as an integral
part of the welder.
(2) A switch or circuit breaker must be provided by which each resistance
welder and its control equipment can be isolated from the supply circuit.
The ampere rating of this disconnecting means must not be less than the
supply conductor ampacity.
WAC 296-307-37012
What requirements apply to electrically driven or controlled irrigation
machines?
(1) If an electrically driven or controlled irrigation machine has a
stationary point, a driven ground rod must be connected to the machine
at the stationary point for lightning protection.
(2) The main disconnecting means for a center pivot irrigation machine
must be located at the point of connection of electrical power to the
machine and must be readily accessible and capable of being locked in
the open position. A disconnecting means must be provided for each motor
and controller.
WAC
296-307-372 covers the requirements for electric equipment
and wiring in locations that are classified based on the properties
of the flammable vapors, liquids or gases, or combustible dusts
or fibers that may be present and the likelihood that a flammable
combustible concentration or quantity is present. Each room, section,
or area must be considered individually to determine its classification.
All requirements in this part apply to hazardous locations, unless otherwise
indicated.
These hazardous locations are classified as follows:(1) “Class I locations”
are those in which flammable gases or vapors are or may be present in
the air in quantities sufficient to produce explosive or ignitable mixtures.
They include the following:
(a) Class I, Division 1 locations are those where:
(i) Hazardous concentrations of flammable gases or vapors may exist
under normal operating conditions; or
(ii) Hazardous concentrations of such gases or vapors may exist frequently
because of repair or maintenance operations or because of leakage;
or
(iii) Breakdown or faulty operation of equipment or processes might
release hazardous concentrations of flammable gases or vapors, and
might also cause simultaneous failure of electric equipment.
This classification usually includes locations where:
Volatile flammable liquids or liquefied flammable gases are transferred
from one container to another;
Interiors of spray booths and areas in the vicinity of spraying
and painting operations where volatile flammable solvents are
used;
Locations containing open tanks or vats of volatile flammable
liquids;
Drying rooms or compartments for the evaporation of flammable
solvents;
Locations containing fat and oil extraction equipment using volatile
flammable solvents;
Gas generator rooms and other portions of gas manufacturing plants
where flammable gas may escape;
Inadequately ventilated pump rooms for flammable gas or for volatile
flammable liquids;
The interiors of refrigerators and freezers in which volatile
flammable materials are stored in open, lightly stoppered, or
easily ruptured containers; and
All other locations where ignitable concentrations of flammable
vapors or gases are likely to occur in the course of normal operations.
(b) Class I, Division 2 locations are those where:
(i) Volatile flammable liquids or flammable gases are handled, processed,
or used, but in which the hazardous liquids, vapors, or gases are
normally confined within closed containers or systems from which they
can escape only in an accidental rupture or breakdown of containers
or systems, or in case of abnormal operation of equipment; or
(ii) Hazardous concentrations of gases or vapors are normally prevented
by positive mechanical ventilation, and which might become hazardous
through failure or abnormal operation of the ventilating equipment;
or
(iii) They are adjacent to a Class I, Division 1 location, and to
which hazardous concentrations of gases or vapors might occasionally
be communicated unless prevented by adequate positive-pressure ventilation
from a source of clean air, and effective safeguards against ventilation
failure are provided.
This classification usually includes locations where:
Volatile flammable liquids or flammable gases or vapors are used,
but which would become hazardous only in case of an accident or unusual
operating condition. The quantity of flammable material that might
escape in case of accident, the adequacy of ventilating equipment,
the total area involved, and the record of the industry or business
with respect to explosions or fires are all factors to consider in
determining the classification.
Piping without valves, checks, meters, and similar devices would
not ordinarily introduce a hazardous condition even though used for
flammable liquids or gases. Locations used for the storage of flammable
liquids or a liquefied or compressed gases in sealed containers are
not normally considered hazardous unless also subject to other hazardous
conditions.
Electrical conduits and their enclosures separated from process fluids
by a single seal or barrier are Division 2 locations if the outside
of the conduit and enclosures is a nonhazardous location.
(2) “Class II locations” are those that are hazardous because of the
presence of combustible dust. They include the following:
(a) Class II, Division 1 locations are those where:
(i) Combustible dust is or may be suspended in the air under normal
operating conditions, in quantities sufficient to produce explosives
or ignitable mixtures; or
(ii) Mechanical failure or abnormal operation of machinery or equipment
might produce explosive or ignitable, and might also provide a source
of ignition through simultaneous failure of electric equipment, operation
of protection devices, or from other causes; or
(iii) Combustible dusts of an electrically conductive nature may
be present.
This classification may include areas of grain handling and processing
plants, starch plants, sugar-pulverizing plants, malting plants, hay-grinding
plants, coal pulverizing plants, areas where metal dusts and powders
are produced or processed, and other similar locations that contain
dust producing machinery and equipment (except where the equipment is
dust-tight or vented to the outside). These areas would have combustible
dust in the air, under normal operating conditions, in quantities sufficient
to produce explosive or ignitable mixtures.
Combustible dusts that are electrically nonconductive include dusts
produced in the handling and processing of grain and grain products,
pulverized sugar and cocoa, dried egg and milk powders, pulverized spices,
starch and pastes, potato and wood flour, oil meal from beans and seed,
dried hay, and other organic materials that may produce combustible
dusts when processed or handled. Dusts containing magnesium or aluminum
are particularly hazardous and the use of extreme caution is necessary
to avoid ignition and explosion.
(b) Class II, Division 2 location are those where:
(i) Combustible dust is not normally suspended in the air in quantities
sufficient to produce explosive or ignitable mixtures; and dust accumulations
are normally insufficient to interfere with the normal operation of
electrical equipment or other apparatus; or
(ii) Dust may be in suspension in the air as a result of infrequent
malfunctioning of handling or processing equipment, and resulting
dust accumulations may be ignitable by abnormal operation or failure
of electrical equipment or other apparatus.
This classification includes locations where dangerous concentrations
of suspended dust would not be likely but where dust accumulations might
form on or in the vicinity of electric equipment. These areas may contain
equipment from which appreciable quantities of dust would escape under
abnormal operating conditions or be adjacent to a Class II Division
1 location into which an explosive or ignitable concentration of dust
may be suspended under abnormal operating conditions.
(3) “Class III locations” are those that are hazardous because
of the presence of easily ignitable fibers or flyings but in which such
fibers or flyings are not likely to be suspended in the air in quantities
sufficient to produce ignitable mixtures. They include the following:
(a) Class III, Division 1 locations are those where easily ignitable
fibers or materials producing combustible flyings are handled, manufactured,
or used.
Such locations usually include combustible fiber manufacturing and
processing plants; cotton gins and cottonseed mills; flax-processing
plants; and industries involving similar hazardous processes or conditions.
Easily ignitable fibers and flyings include rayon, cotton (including
cotton linters and cotton waste), sisal or henequen, istle, jute, hemp,
tow, cocoa fiber, oakum, baled waste kapok, Spanish moss, excelsior,
and other materials of similar nature.
(b) Class III, Division 2 locations are those where easily ignitable
fibers are stored or handled, except in process of manufacture.
WAC 296-307-37209
What equipment, wiring methods, and installations may be used in hazardous
locations?
Equipment, wiring methods, and installations of equipment in hazardous
locations must be intrinsically safe, or approved for the hazardous location,
or safe for the hazardous location. Requirements for each of these options
are as follows:
(1) Equipment and associated wiring approved as intrinsically safe are
permitted in any hazardous location for which it is approved.
(2) Requirements to be approved for the hazardous location:
(a) Equipment must be approved for the class of location and for the
ignitable or combustible properties of the specific gas, vapor, dust,
or fiber that will be present.
(b) Equipment must be marked to show the class, group, and operating
temperature or temperature range, based on operation in a 40 degrees
C ambient, for which it is approved. The temperature marking must be
a maximum of the ignition temperature of the specific gas or vapor to
be encountered. The following provisions apply to specific equipment:
(i) Nonheat-producing equipment, such as junction boxes, conduit,
and fittings, and heat-producing equipment with a maximum temperature
of 100 degrees C (212 degrees F) need not have a marked operating
temperature or temperature range.
(ii) Fixed lighting fixtures marked for use in Class I, Division
2 locations only, need not be marked to indicate the group.
(iii) Fixed general-purpose equipment in Class I locations (other
than lighting fixtures) that is acceptable for use in Class I, Division
2 locations need not be marked with the class, group, division, or
operating temperature.
(iv) Fixed dust-tight equipment (other than lighting fixtures) that
is acceptable for use in Class II, Division 2 and Class III locations
need not be marked with the class, group, division, or operating temperature.
(3) Equipment that is safe for the location shall be of a type and design
that provides protection from the hazards arising from combustible and
flammable vapors, liquids, gases, dusts, or fibers.
Note: Equipment that meets the requirements of The
National Electrical Code, NFPA 70, shall be considered in compliance
with the requirements of
WAC 296-307-372.
WAC 296-307-37215
Which equipment may be used in Division 1 and 2 locations?
Equipment that has been approved for a Division 1 location may
be installed in a Division 2 location of the same class and group. General-purpose
equipment or equipment in general-purpose enclosures may be installed
in Division 2 locations if the equipment does not constitute a source
of ignition under normal operating conditions.
WAC 296-307-37218
What requirements apply to motors and generators used in hazardous locations?
In Class I, Division 1 locations, motors, generators and other rotating
electric machinery must be:
(1) Approved for Class I, Division 1 locations (explosion-proof); or
(2) Of the totally enclosed type supplied with positive-pressure ventilation
from a source of clean air with discharge to a safe area, arranged to
prevent energizing of the machine until ventilation has been established
and the enclosure has been purged with at least 10 volumes of air, and
also arranged to automatically deenergize the equipment when the air supply
fails; or
(3) Of the totally enclosed inert-gas-filled type supplied with a suitable
reliable source of inert gas for pressuring the enclosure, with devices
provided to ensure a positive pressure in the enclosure and arranged to
automatically deenergize the equipment when the gas supply fails; or
(4) Of a type designed to be submerged in a liquid that is flammable
only when vaporized and mixed with air, or in a gas or vapor at a pressure
greater than atmospheric and which is flammable only when mixed with air;
and the machine is arranged to prevent energizing it until it has been
purged with the liquid or gas to exclude air, and also arranged to automatically
deenergize the equipment when the supply of liquid, or gas or vapor fails
or the pressure is reduced to atmospheric.
Totally enclosed type (2) and (3) motors must have no external surface
with a Celsius operating temperature greater than 80% of the ignition
temperature of the gas or vapor involved, as determined by ASTM test procedure
(Designation: D-2155-69). Appropriate devices must be provided to detect
an increase in temperature of the motor beyond design limits and automatically
deenergize the equipment or provide an adequate alarm. Auxiliary equipment
must be approved for the location in which it is installed.
WAC 296-307-37403
What requirements apply to systems over 600 volts, nominal?
(1) Wiring methods for fixed installations over 600 volts, nominal, must
meet the following requirements:
(a) Above-ground conductors must be installed in rigid metal conduit,
in intermediate metal conduit, in cable trays, in cablebus, in other
suitable raceways, or as open runs of metal-clad cable suitable for
the use and purpose. Open runs of nonmetallic-sheathed cable or of bare
conductors or busbars must be installed in locations accessible only
to qualified persons. Metallic shielding components, such as tapes,
wires, or braids for conductors, must be grounded. Open runs of insulated
wires and cables with a bare lead sheath or a braided outer covering
must be supported to prevent physical damage to the braid or sheath.
(b) Conductors emerging from the ground must be enclosed in approved
raceways.
(2) Interrupting and isolating devices must meet the following requirements:
(a) Circuit breaker installations located indoors must consist of metal-enclosed
units or fire-resistant cell-mounted units. Circuit breakers must be
open mounted only in locations that are accessible only to qualified
persons. A means of indicating the open and closed position of circuit
breakers must be provided.
(b) Fused cutouts installed in buildings or transformer vaults must
be approved for the purpose. They must be readily accessible for fuse
replacement.
(c) A means must be provided to completely isolate equipment for inspection
and repairs. Isolating means that are not designed to interrupt the
load current of the circuit must be either interlocked with an approved
circuit interrupter or provided with a sign warning against opening
them under load.
(3) Mobile and portable equipment must meet the following requirements:
(a) A metallic enclosure must be provided on the mobile machine for
enclosing the terminals of the power cable. The enclosure must include
provisions for a solid connection for the ground wire terminal to effectively
ground the machine frame. The method of cable termination used must
prevent any strain or pull on the cable from stressing the electrical
connections. The enclosure must be lockable so only authorized qualified
persons may open it and must be marked with a sign warning of the presence
of energized parts.
(b) All energized switching and control parts must be enclosed in grounded
metal cabinets or enclosures. Circuit breakers and protective equipment
must have the operating means projecting through the metal cabinet or
enclosure so these units can be reset without opening locked doors.
Enclosures and metal cabinets must be locked so that only authorized
qualified persons have access and must be marked with a sign warning
of the presence of energized parts. Collector ring assemblies on revolving
machines (shovels, draglines, etc.,) must be guarded.
(4) Tunnel installations of high-voltage power distribution and utilization
equipment that is portable or mobile, such as substations, trailers, cars,
mobile shovels, draglines, hoists, drills, dredges, compressors, pumps,
conveyors, and underground excavators must meet the following requirements:
(a) Conductors in tunnels must be installed in one or more of the following:
(i) Metal conduit or other metal raceway;
(ii) Type MC cable; or
(iii) Other approved multiconductor cable.
Conductors must also be located or guarded to protect them from physical
damage. Multiconductor portable cable may supply mobile equipment.
An equipment grounding conductor must be run with circuit conductors
inside the metal raceway or inside the multiconductor cable jacket.
The equipment grounding conductor may be insulated or bare.
(b) Bare terminals of transformers, switches, motor controllers, and
other equipment must be enclosed to prevent accidental contact with
energized parts. Enclosures used in tunnels must be drip-proof, weatherproof,
or submersible as required by environmental conditions.
(c) A disconnecting means that simultaneously opens all ungrounded
conductors must be installed at each transformer or motor location.
(d) All nonenergized metal parts of electric equipment and metal raceways
and cable sheaths must be effectively grounded and bonded to all metal
pipes and rails at the portal and at maximum intervals of 1000 feet
throughout the tunnel.
WAC 296-307-37406
What requirements apply to emergency power systems?
This section applies to circuits, systems, and equipment intended to
supply power for illumination and special loads, in the event of failure
of the normal supply.
(1) Emergency circuit wiring must be kept entirely independent of all
other wiring and equipment and must not enter the same raceway, cable,
box, or cabinet as other wiring.
Exception: This does not apply where common circuit
elements suitable for the purpose are required, or for transferring power
from the normal to the emergency source.
(2) Where emergency lighting is necessary, the system must be arranged
so that the failure of any individual lighting element, such as a burned
out light bulb, cannot leave any space in total darkness.
WAC 296-307-37409
How are Class 1, Class 2, and Class 3 remote control, signaling, and power-limited
circuits classified?
(1) Class 1, Class 2, or Class 3 remote control, signaling, or power-limited
circuits are characterized by their usage and electrical power limitation
which differentiates them from light and power circuits. These circuits
are classified according to their voltage and power limitations as follows.
(a) Class 1 circuits.
(i) A Class 1 power-limited circuit is supplied from a source with
a maximum rated output of 30 volts and 1000 volt-amperes.
(ii) A Class 1 remote control circuit or a Class 1 signaling circuit
has a maximum voltage of 600 volts; however, the power output of the
source need not be limited.
(b) Class 2 and Class 3 circuits.
(i) Power for Class 2 and Class 3 circuits is limited either inherently
(in which no overcurrent protection is required) or by a combination
of a power source and overcurrent protection.
(ii) The maximum circuit voltage is 150 volts AC or DC for a Class
2 inherently limited power source, and 100 volts AC or DC for a Class
3 inherently limited power source.
(iii) The maximum circuit voltage is 30 volts AC and 60 volts DC
for a Class 2 power source limited by overcurrent protection, and
150 volts AC or DC for a Class 3 power source limited by overcurrent
protection.
(c) The maximum circuit voltages in (a) and (b) of this subsection
apply to sinusoidal AC or continuous DC power sources, and where wet
contact is unlikely.
(2) A Class 2 or Class 3 power supply unit must be durably and visibly
marked to indicate the class of supply and its electrical rating.
WAC 296-307-37412
What requirements apply to fire protective signaling systems?
(1) Fire protective signaling circuits must be classified either as nonpower
limited or power limited.
(2) The power sources for use with fire protective signaling circuits
must be either power limited or nonlimited as follows:
(a) The power supply of nonpower-limited fire protective signaling
circuits must have a maximum output voltage of 600 volts.
(b) The power for power-limited fire protective signaling circuits
must be either inherently limited, in which no overcurrent protection
is required, or limited by a combination of power source and overcurrent
protection.
(3) Nonpower-limited fire protective signaling circuits and Class 1 circuits
may occupy the same enclosure, cable, or raceway if all conductors are
insulated for maximum voltage of any conductor within the enclosure, cable
or raceway. Power supply and fire protective signaling circuit conductors
are permitted in the same enclosure, cable, or raceway only if connected
to the same equipment.
(4) Where open conductors are installed, power-limited fire protective
signaling circuits must be separated at least 2 inches from conductors
of any light, power, Class 1, and nonpower-limited fire protective signaling
circuits unless using a special and equally protective method of conductor
separation. Cables and conductors of two or more power-limited fire protective
signaling circuits or Class 3 circuits are permitted in the same cable,
enclosure, or raceway. Conductors of one or more Class 2 circuits are
permitted within the same cable, enclosure, or raceway with conductors
of power-limited fire protective signaling circuits if the insulation
of Class 2 circuit conductors in the cable, enclosure, or raceway is at
least that needed for the power-limited fire protective signaling circuits.
(5) Fire protective signaling circuits must be identified at terminal
and junction locations in a manner that will prevent unintentional interference
with the signaling circuit during testing and servicing. Power-limited
fire protective signaling circuits must be visibly and durably marked
at terminations.
WAC
296-307-376 applies to work performed on exposed live parts
(involving either direct contact or contact by means of tools
or materials) or near enough to them for employees to be exposed
to any hazard they present.
Only qualified persons may work on electric circuit parts of equipment
that have not been deenergized under the procedures of WAC
296-307-37807. Qualified persons must be capable of working
safely on energized circuits and must be familiar with the proper
use of special precautionary techniques, personal protective equipment,
insulating and shielding materials, and insulated tools.
WAC 296-307-37609
What requirements apply to working near low voltage lines?
When employees are working near energized electrical service conductors
operating at 750 volts or less, employees must work in a manner to prevent
contact with the energized conductors.
WAC 296-307-37612
What requirements apply to qualified persons working near overhead lines?
When a qualified person is working near overhead lines, whether in an
elevated position or on the ground, the person must not approach,
or take any conductive object without an approved insulating handle,
closer to exposed energized parts than shown in WAC
296-307-150 unless:
(1) The person is insulated from the energized part (gloves, with sleeves
if necessary, rated for the voltage involved are considered to be insulation
of the person from the energized part on which work is performed); or
(2) The energized part is insulated both from all other conductive objects
at a different potential and from the person; or
(3) The person is insulated from all conductive objects at a potential
different from that of the energized part.
WAC 296-307-37615
What requirements apply to vehicles and mechanical equipment near overhead
lines?
(1) Any vehicle or mechanical equipment that may have parts of its structure
elevated near energized overhead lines must be operated so that a clearance
of 10 ft. is maintained. If the voltage is higher than 50kV, the clearance
must be increased 0.4 inch for every 1kV over the voltage. The clearance
may be reduced only if:
(a) The vehicle is in transit with its structure lowered, the clearance
may be reduced to 4 ft. If the voltage is higher than 50kV, the clearance
must be increased 0.4 inch for every 1kV over that voltage.
(b) Insulating barriers are installed to prevent contact with the lines,
and if the barriers are rated for the voltage of the line being guarded
and are not a part of or an attachment to the vehicle or its raised
structure, the clearance may be reduced to a distance within the designed
working dimensions of the insulating barrier.
(2) If the equipment is an aerial lift insulated for the voltage involved,
and if the work is performed by a qualified person, the clearance
(between the uninsulated portion of the aerial lift and the power
line) may be reduced to the distance given in WAC
296-307-150.
(3) Employees standing on the ground must not contact the vehicle or
mechanical equipment or any of its attachments, unless:
(a) The employee is using protective equipment rated for the voltage;
or
(b) The equipment is located so that no uninsulated part of its structure
(that portion of the structure that provides a conductive path to employees
on the ground) can come closer to the line than permitted in this section.
(4) If any vehicle or mechanical equipment that may have parts of its
structure elevated near energized overhead lines is intentionally grounded,
employees working on the ground near the point of grounding must not stand
at the grounding location whenever there is a possibility of overhead
line contact. Additional precautions, such as the use of barricades or
insulation, must be taken to protect employees from hazardous ground potentials,
depending on earth resistivity and fault currents, which can develop within
the first few feet or more outward from the grounding point.
WAC 296-307-37618
What lighting must be provided for employees working near exposed energized
parts?
(1) Employees must not enter spaces containing exposed energized parts,
unless lighting is provided that enables the employees to perform the
work safely.
(2) Where lack of lighting or an obstruction prevents an employee from
seeing the work to be performed, employees must not perform tasks near
exposed energized parts. Employees shall not reach blindly into areas
that may contain energized parts.
WAC 296-307-37621
What requirements apply to working near exposed energized parts in confined
spaces?
(1) For working in a confined or enclosed space (such as a manhole or
vault) that contains exposed energized parts, the employer shall provide,
and the employee must use, protective shields, protective barriers, or
insulating materials that are necessary to avoid contact with these parts.
Doors, hinged panels, and the like must be secured to prevent swinging
into an employee and causing the employee to contact exposed energized
parts.
(2) Conductive materials and equipment that are in contact with any part
of an employee's body shall be handled in a manner that will prevent them
from contacting exposed energized conductors or circuit parts. If an employee
handles long conductive objects (such as ducts and pipes) in areas with
exposed live parts, you must institute work practices (such as the use
of insulation, guarding, and material handling techniques) that will minimize
the hazard.
(3) Portable ladders must have nonconductive siderails if they are used
where the employee or the ladder could contact exposed energized parts.
(4) Conductive articles of jewelry and clothing shall not be worn if
they might contact exposed energized parts.
WAC 296-307-37624
What housekeeping requirements apply to working near exposed energized
parts?
(1) Where live parts present an electrical contact hazard, employees
must not perform housekeeping duties near enough to the parts that there
is a possibility of contact, unless adequate safeguards (such as insulating
equipment or barriers) are provided.
(2) Electrically conductive cleaning materials (including conductive
solids such as steel wool, metalized cloth, and silicon carbide, as well
as conductive liquid solutions) must not be used in proximity to energized
parts unless procedures are followed that will prevent electrical contact.
Only a qualified person following the requirements of this section may
defeat an electrical safety interlock, and then only temporarily while
he or she is working on the equipment. The interlock system must be returned
to its operable condition when this work is completed.
(1)
WAC 296-307-376 and 296-307-378
cover electrical safety-related work practices for both qualified
persons (those who have training in avoiding the electrical hazards
of working on or near exposed energized parts) and unqualified
persons (those with little or no such training) working on, near,
or with the following installations:
(a) Installations of electric conductors and equipment within or on
buildings or other structures, and on other premises such as yards,
parking, and other lots, and industrial substations;
(b) Installations of conductors that connect to the supply of electricity;
(c) Installations of other outside conductors on the premises; and
(d) Installations of optical fiber cable where such installations are
made along with electric conductors.
(2) WAC
296-307-376 and 296-307-378
cover work performed by unqualified persons on, near, or with
the installations listed in subsection (3) of this section.
(3) WAC
296-307-376 and 296-307-378
do not apply to work performed by qualified persons on or directly
associated with the following installations:
(a) Installations for the generation, control, transformation, transmission,
and distribution of electric energy (including communication and metering)
located in buildings used for such purposes or located outdoors.
Work on or directly associated with generation, transmission, or distribution
installations includes:
(i) Work performed directly on installations, such as repairing distribution
lines or repairing a feed-water pump for the boiler in a generating
plant.
(ii) Work directly associated with installations, such as line-clearance
tree trimming and replacing utility poles.
(iii) Work on electric utilization circuits in a generating plant
where:
The circuits are combined with installations of power generation
equipment or circuits; and
The generation equipment or circuits present greater electrical
hazards than those posed by the utilization equipment or circuits
(such as exposure to higher voltages or lack of overcurrent protection).
(b) Installations in watercraft, railway rolling stock, aircraft, or
automotive vehicles other than mobile homes and recreational vehicles.
(c) Installations of railways for generation, transformation, transmission,
or distribution of power used exclusively for operation of rolling stock
or installations of railways used exclusively for signaling and communication
purposes.
WAC 296-307-37803
How must employees be trained on safety practices?
(1) The training requirements in this section apply to employees
who face a risk of electrical shock that is not reduced to a safe
level by the electrical installation requirements of WAC
296-307-362 through 296-307-374.
(2) Training contents must include the following:
(a) Employees must be trained in and familiar with the safety-related
work practices required by WAC
296-307-376 through 296-307-378
that apply to their job assignments.
(b) Employees who are covered by this section but who are not qualified
persons must also be trained in and familiar with any electrically related
safety practices that are not covered by this standard, but that are
necessary for their safety.
(c) Qualified persons must, at a minimum, be trained in and familiar
with the following:
(i) The skills and techniques necessary to distinguish exposed live
parts from other parts of electric equipment;
(ii) The skills and techniques necessary to determine the nominal
voltage of exposed live parts; and
(iii) The clearance distance specified in WAC
296-307-376 and the corresponding voltages to which the
qualified person will be exposed.
Note 1: For the purposes of WAC
296-307-376 and 296-307-378,
an employee must have the training required for a qualified person
in order to be considered a qualified person.
Note 2: Qualified persons whose work on energized
equipment involves either direct contact or contact by means of
tools or materials must also have the training needed to meet
WAC
296-307-376.
(3) You must provide either classroom or on-the-job training. The degree
of training provided must be determined by the risk to the employee.
WAC 296-307-37805
How must safety-related work practices be chosen and used?
Safety-related work practices must be used to prevent electric shock
or other injuries resulting from either direct or indirect electrical
contacts, when work is performed near or on equipment or circuits that
are or may be energized. The specific safety-related work practices must
be consistent with the nature and extent of the associated electrical
hazards.
(1) When an employee may be exposed to live parts, they must be deenergized
before the employee works on or near them, unless deenergizing introduces
other hazards or is infeasible due to equipment design or operational
limitations. Live parts that operate at less than 50 volts to ground need
not be deenergized if there will be no increased exposure to electrical
burns or to explosion due to electric arcs.
Note 1: Examples of other hazards include deactivation
of emergency alarm systems, shutdown of hazardous location ventilation
equipment, or removal of illumination for an area.
Note 2: An example of work that may be performed
on or near energized circuit parts because of unfeasibility due to equipment
design or operational limitations is testing of electric circuits that
can only be performed with the circuit energized.
(2) If the exposed live parts are not deenergized (for reasons of increased
or additional hazards or unfeasibility), other safety-related work practices
must be used to protect employees who may be exposed to the electrical
hazards involved. Such work practices must protect employees against contact
with energized circuit parts directly with any part of their body or indirectly
through some other conductive object. The work practices must be suitable
for the voltage level of the exposed electric conductors or circuit parts.
WAC 296-307-37807
What work practices must be followed for work on exposed deenergized parts?
(1) This section applies to work on exposed deenergized parts or near
enough to them to expose the employee to any electrical hazard
they present. Conductors and parts of electric equipment that
have been deenergized but have not been locked out or tagged must
be treated as energized parts, and WAC
296-307-376 applies to work on or near them.
(2) While any employee is exposed to contact with parts of fixed electric
equipment or circuits which have been deenergized, the circuits energizing
the parts must be locked out or tagged or both according to the requirements
of this section. The requirements must be followed in the order in which
they are presented.
“Fixed equipment” means equipment that is fastened or connected
by permanent wiring methods.
Note: Lockout and tagging procedures that
comply with WAC 296-307-320 will also be deemed to comply with
WAC
296-307-37807 through 296-307-37817
if:
The procedures address the electrical safety hazards covered by this
part; and
WAC 296-307-37809
Must an employer have a written copy of lockout-tagout procedures?
The employer must maintain a written copy of the procedures outlined
in WAC
296-307-37807 through 296-307-37817
and must make it available for inspection by us or by employees.
WAC 296-307-37811
What work practices must be followed for deenergizing equipment?
(1) Safe procedures for deenergizing circuits and equipment must be determined
before circuits or equipment are deenergized.
(2) The circuits and equipment to be worked on must be disconnected from
all electric energy sources. Control circuit devices, such as push buttons,
selector switches, and interlocks, must not be used as the sole means
for deenergizing circuits or equipment. Interlocks for electric equipment
must not be used as a substitute for lockout and tagging procedures.
(3) Stored electric energy which might endanger employees must be released.
Capacitors must be discharged and high capacitance elements must be short-circuited
and grounded, if the stored electric energy might endanger employees.
Note: Capacitors or associated equipment handled
in meeting this requirement must be treated as energized.
(4) Stored nonelectrical energy in devices that could reenergize electric
circuit parts must be blocked or relieved to the extent that the circuit
parts could not be accidentally energized by the device.
(1) A lock and a tag must be placed on each disconnecting means used
to deenergize circuits and equipment on which work is to be performed,
except as provided in subsections (3) and (5) of this section. The lock
must be attached to prevent anyone from operating the disconnecting means
unless they resort to undue force or the use of tools.
(2) Each tag must have a statement prohibiting unauthorized operation
of the disconnecting means and removal of the tag.
(3) If a lock cannot be applied, or if tagging procedures will provide
a level of safety equivalent to that obtained by the use of a lock, a
tag may be used without a lock.
(4) A tag used without a lock must be supplemented by at least one additional
safety measure that provides a level of safety equivalent to that obtained
by the use of a lock. Examples of additional safety measures include the
removal of an isolating circuit element, blocking of a controlling switch,
or opening of an extra disconnecting device.
(5) A lock may be placed without a tag only under the following conditions:
(a) Only one circuit or piece of equipment is deenergized; and
(b) The lockout period does not extend beyond the work shifts; and
(c) Employees exposed to the hazards associated with reenergizing the
circuit or equipment are familiar with this procedure.
WAC 296-307-37815
What work practices must be followed to verify deenergization?
The requirements of this section must be met before any circuits or
equipment can be considered and worked as deenergized.
(1) A qualified person must operate the equipment operating controls
or otherwise verify that the equipment cannot be restarted.
(2) A qualified person must use test equipment to test the circuit elements
and electrical parts of equipment to which employees will be exposed and
shall verify that the circuit elements and equipment parts are deenergized.
The test must also determine if any energized conditions exists as a result
of inadvertently induced voltage or unrelated voltage backfeed even though
specific parts of the circuit have been deenergized and presumed to be
safe. If the circuit to be tested is over 600 volts, nominal, the test
equipment must be checked for proper operation immediately before and
immediately after this test.
WAC 296-307-37817
What work practices must be followed when reenergizing equipment?
These requirements must be met, in the order given, before circuits or
equipment are reenergized, even temporarily.
(1) A qualified person must conduct tests and visual inspections as necessary
to verify that all tools, electrical jumpers, shorts, grounds, and other
devices have been removed, so that the circuits and equipment can be safely
energized.
(2) Employees exposed to the hazards associated with reenergizing the
circuit or equipment must be warned to stay clear of circuits and equipment.
(3) Each lock and tag must be removed by the employee who applied it
or under his or her direct supervision. However, if this employee is absent
from the workplace, then the lock or tag must be removed by a qualified
person designated to perform this task if:
(a) The employer ensures that the employee who applied the lock or
tag is not available at the workplace; and
(b) The employer ensures that the employee is aware that the lock or
tag has been removed before resuming work at that workplace.
(4) There shall be a visual determination that all employees are clear
of the circuits and equipment.
WAC 296-307-37819
What safety-related work practices relate to portable electric equipment?
This section applies to using cord-connected and plug-connected equipment,
including flexible cord sets (extension cords).
(1) Portable equipment must be handled in a manner that will not cause
damage. Flexible electric cords connected to equipment must not be used
for raising or lowering the equipment. Flexible cords must not be fastened
with staples or otherwise hung in a way that could damage the outer jacket
or insulation.
(2) Visual inspection requirements:
(a) Portable cord-connected and plug-connected equipment and flexible
cord sets must be visually inspected before use on any shift for external
defects (such as loose parts, deformed and missing pins, or damage to
outer jackets or insulation) and for evidence of possible internal damage
(such as pinched or crushed outer jacket). Cord-connected and plug-connected
equipment and flexible cord sets that remain connected once they are
in place and are not exposed to damage need not be visually inspected
until they are relocated.
(b) If there is a defect or evidence of damage that might expose an
employee to injury, the defective or damaged items must be removed from
service, and no employee shall use it until repairs and tests necessary
to render the equipment safe have been made.
(c) When an attachment plug is to be connected to a receptacle (including
any on a cord set), the relationship of the plug and receptacle contacts
must first be checked to ensure they are of proper mating configurations.
(3) Requirements for grounding-type equipment:
(a) A flexible cord used with grounding-type equipment must contain
an equipment grounding conductor.
(b) Attachment plugs and receptacles must not be connected or altered
in a manner that would prevent proper continuity of the equipment grounding
conductor at the point where plugs are attached to receptacles. These
devices must not be altered to allow the grounding pole of a plug to
be inserted into slots intended for connection to the current-carrying
conductors.
(c) Adapters that interrupt the continuity of the equipment grounding
connection are prohibited.
(4) Portable electric equipment and flexible cords used in highly conductive
work locations, or in locations where employees are likely to contact
water or conductive liquids, must be approved for those locations.
(5) Connecting attachment plugs.
(a) Employees' hands must not be wet when plugging and unplugging flexible
cords and cord-connected and plug-connected equipment, if energized
equipment is involved.
(b) Energized plug and receptacle connections must be handled only
with insulating protective equipment if the condition of the connection
could provide a conducting path to the employee's hand. For example:
If a cord connector is wet from being immersed in water.
(c) Locking-type connectors must be properly secured after connection.
WAC 296-307-37821
What safety-related work practices relate to electric power and lighting
circuits?
(1) Load rated switches, circuit breakers, or other devices specifically
designed as disconnecting means must be used for the opening, reversing,
or closing of circuits under load conditions. Any cable connectors other
than the load-break type, fuses, terminal lugs, and cable splice connections
are prohibited for such purposes, except in an emergency.
(2) After a circuit is deenergized by a circuit protective device, the
circuit must not be manually reenergized until it has been determined
that the equipment and circuit can be safety energized. This repetitive
manual reclosing of circuit breakers or reenergizing circuits through
replaced fuses is prohibited.
Note: When it can be determined from the design
of the circuit and the overcurrent devices involved that the automatic
operation of a device was caused by an overload rather than a fault connection,
no examination of the circuit or connected equipment is needed before
the circuit is reenergized.
(3) Overcurrent protection of circuits and conductors must not be modified,
even on a temporary basis, beyond that allowed by this part for the installation
safety requirements for overcurrent protection.
WAC 296-307-37823
What safety-related work practices relate to test instruments and equipment?
(1) Only qualified persons may perform testing work on electric circuits
or equipment.
(2) Test instruments and equipment and all associated test leads, cables,
power cords, probes, and connectors must be visually inspected for external
defects and damage before the equipment is used. If there is a defect
or evidence of damage that might expose an employee to injury, the defective
or damaged item must be removed from service, and no employee may use
it until necessary repairs and tests to render the equipment safe have
been made.
(3) Test instruments and equipment and their accessories must be rated
for the circuits and equipment to which they will be connected and must
be designed for the environment in which they will be used.
WAC 296-307-37825
What safety-related work practices relate to flammable materials?
Where flammable materials are present only occasionally, electric equipment
capable of igniting them must not be used, unless measures are taken to
prevent hazardous conditions from developing.
Such materials include, but are not limited to: flammable gases, vapors,
or liquids; combustible dust; and ignitable fibers or flyings.
Note: Electrical installation requirements for locations
where flammable materials are present on a regular basis are contained
in WAC
296-307-372.
(1) Employees working in the areas where there are potential electrical
hazards must have and use electrical protective equipment that is appropriate
for the specific parts of the body to be protected and for the work to
be performed.
(2) If the insulating capability of protective equipment may be subject
to damage during use, the insulating material must be protected.
For example: An outer covering of leather is sometimes
used to protect rubber insulating material.
(3) Employees must wear nonconductive head protection wherever there
is a danger of head injury from electric shock or burns due to contact
with exposed energized parts.
(4) Employees must wear protective equipment for the eyes or face wherever
there is danger of injury to the eyes or face from electrical arcs or
flashes or from flying objects resulting from electrical explosion.
WAC 296-307-38006
What requirements apply to general protective equipment and tools?
(1) When working near exposed energized conductors or circuit parts,
each employee must use insulated tools or handling equipment if the tools
or handling equipment might make contact with such conductors or parts.
If the insulating capability of insulated tools or handling equipment
is subject to damage, the insulating material must be protected.
(2) Ropes and handlines used near exposed energized parts must be nonconductive.
(3) Protective shields, protective barriers, or insulating materials
must be used to protect each employee from shock, burns, or other electrically
related injuries while that employee is working near exposed energized
parts that might be accidentally contacted or where dangerous electric
heating or arcing might occur. When normally enclosed live parts are exposed
for maintenance or repair, they must be guarded to protect unqualified
persons from contact with the live parts.
(4) Altering techniques must be used to warn and protect employees from
hazards that could cause injury due to electric shock, burns, or failure
of electric equipment parts.
(5) Safety signs, safety symbols, or accident prevention tags must be
used where necessary to warn employees about electrical hazards
that may endanger them, as required by WAC
296-307-330.
WAC 296-307-38012
What electrical requirements apply to electrical protective devices?
Insulating blankets, matting, covers, line hose, gloves, and sleeves
made of rubber must meet the following electrical requirements:
(1) Equipment must be capable of withstanding the a-c proof-test voltage
specified in Table 1 or the d-c proof-test voltage specified in Table
2.
(a) The proof-test must reliably indicate that the equipment can withstand
the voltage involved.
(b) The test voltage must be applied continuously for three minutes
for equipment other than matting and must be applied continuously for
one minute for matting.
(c) Gloves must also be capable of withstanding the a-c proof-test
voltage specified in Table 1 after a sixteen-hour water soak.
(2) When the a-c proof-test is used on gloves, the 60 hertz proof-test
current must not exceed the values specified in Table 1 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 must be computed from the direct
ratio of the frequencies.
(b) For the test, gloves (right side out) must be filled with tap water
and immersed in water to a depth that is in accordance with Table 3.
Water must 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 sixteen-hour water soak, the 60 hertz proof-test current
may exceed the values given in Table 1 by not more than 2 milliamperes.
(3) Equipment that has been subjected to a minimum breakdown voltage
test must not be used for electrical protection.
(4) Material used for Type II insulating equipment must be capable of
withstanding an ozone test, with no visible effects. The ozone test must
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.
Note: Rubber insulating equipment meeting
the following national consensus standards is considered to be
in compliance with WAC
296-307-38009, 296-307-38012,
and 296-307-38015:
American Society for Testing and Materials (ASTM)
D 120-87, Specification for Rubber Insulating Gloves.
ASTM D 178-93, Specification for Rubber Insulating
Matting.
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.
These standards contain specifications for conducting the tests required
in this section.
WAC 296-307-38015
What workmanship and finish requirements apply to electrical protective
devices?
Insulating blankets, matting, covers, line hose, gloves, and sleeves
made of rubber must meet the following workmanship and finish requirements:
(1) Equipment must be free of harmful physical irregularities that can
be detected by the tests or inspections required in WAC
296-307-38012.
(2) Surface irregularities that may be present on all rubber goods because
of imperfections on forms or molds or because of inherent difficulties
in the manufacturing process and that may appear as indentations, protuberances,
or imbedded foreign material are acceptable if:
(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.
WAC 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 Level 1, 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
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 4 Rubber
Insulating Equipment Voltage Requirements
Class of
equipment
Maximum use
voltage1 a-c-rms
Retest voltage
2 a-c-rms
Retest voltage
2 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 5,000 volts phase to phase
or less.
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: (a) If the 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.
2 The 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.
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