296-307-360 Electrical.
296-307-36005 What does this part cover?
296-307-36010 What definitions apply to this part?
296-307-362 General electrical requirements.
296-307-36203 What electrical equipment must be approved?
296-307-36206 How must electrical equipment safety be determined?
296-307-36209 What requirements apply to guarding live parts?
296-307-36212 What workspace must be provided?
296-307-36215 What general requirements apply to splices?
296-307-36218 What protection must be provided against combustible materials?
296-307-36221 How must electrical equipment be marked?
296-307-36224 How must disconnecting means be marked?
296-307-36227 What access and working space must be provided for electrical
equipment over 600 volts, nominal, or less?
296-307-36230 What access and working space must be provided for electrical
equipment over 600 volts, nominal?
296-307-364 Electrical installation and maintenance.
296-307-36403 How must flexible cords and cables be installed and maintained?
296-307-36406 How must attachment plugs and receptacles be installed and
maintained?
296-307-36409 What must employees do when equipment causes electrical shock?
296-307-36412 What grounding and bonding requirements apply to equipment
installation and maintenance?
296-307-36415 What requirements apply to disconnecting means?
296-307-36418 What requirements apply to identification and load rating
of electrical equipment?
296-307-36421 How must equipment be installed in wet locations?
296-307-366 Wiring design and protection.
296-307-36603 How must grounded and grounding conductors be used and identified?
296-307-36606 What ampere rating must outlet devices have?
296-307-36609 What requirements apply to conductors?
296-307-36612 What design an protection requirements apply to service-entrances?
296-307-36615 What overcurrent protection must be provided?
296-307-36618 What premises wiring systems must be grounded?
296-307-36621 Must the conductor be grounded for AC premises wiring?
296-307-36624 What general requirements apply to grounding conductors?
296-307-36627 Must the path to the ground be continuous?
296-307-36630 What supports, enclosures, and equipment must be grounded? 296-307-36633 How must fixed equipment be grounded?
296-307-36636 How must high voltage systems be grounded?
296-307-368 Wiring methods, components, and equipment for general use.
296-307-36803 Does this section apply to factory-assembled equipment?
296-307-36806 What wiring methods must be used for temporary wiring?
296-307-36809 When may cable trays be used?
296-307-36812 What requirements apply to open wiring on insulators?
296-307-36815 What wiring requirements apply to cabinets, boxes, and fittings?
296-307-36818 What requirements apply to switches?
296-307-36821 Where must switchboards and panelboards be located?
296-307-36824 When must conductors be insulated?
296-307-36827 When may flexible cords and cables be used?
296-307-36830 How must flexible cords and cables be identified, spliced,
and terminated?
296-307-36833 What requirements apply to multiconductor portable cables?
296-307-36836 When may fixture wires be used?
296-307-36839 What requirements apply to wiring for lighting fixtures,
lampholders, lamps, and receptacles? 296-307-36842 What requirements apply
to wiring for receptacles, cord connectors and attachment plugs (caps)?
296-307-36845 What requirements apply to wiring for appliances?
296-307-36848 What requirements apply to wiring for motors, motor circuits,
and controllers?
296-307-36851 What requirements apply to wiring for transformers?
296-307-36854 What requirements apply to wiring for capacitors?
296-307-36857 How must storage batteries be ventilated?
296-307-36860 What other miscellaneous requirements apply to wiring methods?
296-307-370 Special purpose equipment and installations.
296-307-37003 What requirements apply to cranes, hoists, and runways?
296-307-37006 What requirements apply to elevators, dumbwaiters, escalators,
and moving walks?
296-307-37009 What requirements apply to the disconnecting means for electric
welders?
296-307-37012 What requirements apply to electrically driven or controlled
irrigation machines?
296-307-372 Hazardous (classified) locations.
296-307-37203 What does this section cover?
296-307-37206 What classifications apply to this section?
296-307-37209 What equipment, wiring methods, and installations may be
used in hazardous locations?
296-307-37212 How must conduit be installed in hazardous locations?
296-307-37215 Which equipment may be used in Division 1 and 2 locations?
296-307-37218 What requirements apply to motors and generators used in
hazardous locations?
296-307-374 Special systems.
296-307-37403 What requirements apply to systems over 600 volts, nominal?
296-307-37406 What requirements apply to emergency power systems?
296-307-37409 How are Class 1, Class 2, and Class 3 remote control, signaling,
and power-limited circuits classified?
296-307-37412 What requirements apply to fire protective signaling systems?
296-307-376 Working on or near exposed energized parts.
296-307-37603 What does this section cover?
296-307-37606 Who may work on energized parts?
296-307-37609 What requirements apply to working near low voltage lines?
296-307-37612 What requirements apply to qualified persons working near
overhead lines?
296-307-37615 What requirements apply to vehicles and mechanical equipment
near overhead lines?
296-307-37618 What lighting must be provided for employees working near
exposed energized parts?
296-307-37621 What requirements apply to working near exposed energized
parts in confined spaces?
296-307-37624 What housekeeping requirements apply to working near exposed
energized parts?
296-307-37627 Who may defeat an electrical safety interlock?
296-307-378 Safety-related work practices.
296-307-37801 What does this section cover?
296-307-37803 How must employees be trained on safety practices?
296-307-37805 How must safety-related work practices be chosen and used?
296-307-37807 What work practices must be followed for work on exposed
deenergized parts?
296-307-37809 Must an employer have a written copy of lockout-tagout procedures?
296-307-37811 What work practices must be followed for deenergizing equipment?
296-307-37813 How must locks and tags be applied?
296-307-37815 What work practices must be followed to verify deenergization?
296-307-37817 What work practices must be followed when reenergizing equipment?
296-307-37819 What safety-related work practices relate to portable electric
equipment?
296-307-37821 What safety-related work practices relate to electric power
and lighting circuits?
296-307-37823 What safety-related work practices relate to test instruments
and equipment?
296-307-37825 What safety-related work practices relate to flammable materials?
296-307-380 Electrical protective equipment.
296-307-38003 How must protective equipment be used?
296-307-38006 What requirements apply to general protective equipment and
tools?
296-307-38009 What manufacturing and marking requirements apply to electrical
protective devices?
296-307-38012 What electrical requirements apply to electrical protective
devices?
296-307-38015 What workmanship and finish requirements apply to electrical
protective devices?
296-307-38018 How must electrical protective devices be maintained and
used?
(3) Unless otherwise provided in this chapter all electrical work,
installation, and wire capacities must be according to the National
Electrical Code, NFPA 70-1973; ANSI C1-1971, and all other applicable
standards administered by the department of labor and industries.
“Acceptable” means an installation or equipment that is acceptable
to the department and meets the requirements of this section. An installation
or equipment is acceptable if:
(1) It is accepted, certified, listed, labeled, or otherwise determined
to be safe by a nationally recognized testing laboratory; or
(2) For installations or equipment that no nationally recognized testing
laboratory accepts, certifies, lists, labels, or determines to be safe,
it is inspected or tested by another federal agency, or by state, municipal,
or other local authority responsible for enforcing occupational safety
provisions of the National Electrical Code, and complies with the provisions
of the National Electrical Code, and complies with the provisions of
the National Electrical Code as applied in this section; or
(3) For custom-made equipment or related installations that are designed,
fabricated for, and intended for use by a particular customer, it is
determined to be safe for its intended use by its manufacturer on the
basis of test data that you keep and make available for our inspection.
“Accepted” means an installation that has been inspected and
certified by a nationally recognized testing laboratory to meet specified
plans or procedures of applicable codes.
“Bonding jumper” means a reliable conductor that provides the
correct electrical conductivity between metal parts that are required
to be electrically connected.
“Branch circuits” means the part 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.
“Certified” means equipment that:
Has been tested and found by a nationally recognized testing
laboratory to meet nationally recognized standards, or
to be safe for use in a specified manner; or
Is a kind whose production is periodically inspected by
a nationally recognized testing laboratory; and
Bears a label, tag, or other record of certification.
“Exposed” means a live part that can be accidentally touched
or approached nearer than a safe distance. This term applies to parts
that are not suitably guarded, isolated, or insulated.
“Fixed equipment” means equipment fastened or connected by permanent
wiring methods.
“Ground” means a conducting connection, whether intentional
or accidental, between an electrical circuit or equipment and earth,
or to some conducting body that serves in place of the earth.
“Grounded” means connected to earth or to some conducting body
that serves in place of the earth.
“Isolated” means equipment that is not readily accessible except
through special means of access.
“Labeled” means equipment that has an attached label, symbol,
or other identifying mark of a nationally recognized testing laboratory
that:
Makes periodic inspections of the production of such equipment;
and
Whose labeling indicates compliance with nationally recognized
standards or tests to determine safe use in a specified manner.
“Qualified person” means a person who is familiar with the construction
and operation of the equipment and the hazards involved.
Note 1: Whether an employee is considered a “qualified person” depends
on various circumstances in the workplace. It is possible and likely
for an individual to be considered “qualified” with regard to certain
equipment in the workplace, but “unqualified” as to other equipment.
Note 2: An employee undergoing on-the-job training and who, in the
course of such training, has demonstrated an ability to perform duties
safely at his or her level of training and who is under the direct
supervision of a qualified person is considered a qualified person
for the performance of those duties.
“Shock hazard” exists at an accessible part in a circuit between
the part and ground, or other accessible parts if the potential is more
than 42.4 volts peak and the current through a 1,500 ohm load is more
than 5 milliamperes.
“Weatherproof” means constructed or protected so that exposure
to the weather does not interfere with successful operation. Rainproof,
raintight, or watertight equipment may be considered weatherproof where
weather conditions other than wetness, such as snow, ice, dust, or temperature
extremes, are not a factor.
WAC
296-307-36206 How must electrical equipment safety be determined?
(1) Electrical equipment must be free from hazards to employees. Safety
of equipment must be determined using the following considerations:
(a) Suitability for installation and use according to the
requirements of this part. Suitability of equipment for a
specific purpose may be shown by listing or labeling for
that purpose.
(b) Mechanical strength and durability, including, for parts
designed to enclose and protect other equipment, the adequacy
of the protection provided.
(c) Electrical insulation.
(d) Heating effects under conditions of use.
(e) Arcing effects.
(f) Classification by type, size, voltage, current capacity,
specific use.
(g) Other factors that contribute to the practical safeguarding
of employees using or likely to come in contact with the
equipment.
(2) Listed or labeled equipment must be used or installed according
to any instructions included in the listing or labeling.
(1) Unless otherwise indicated, live parts of electric equipment operating
at 50 volts or more must be guarded against accidental contact by an
approved cabinet or other form of approved enclosure, or by any of the
following:
(a) Location in a room, vault, or similar enclosure that
is accessible only to qualified persons.
(b) Suitable permanent substantial partitions or screens
arranged so that only qualified persons have access to the
area within reach of the live parts. Any openings in such
partitions or screens must be small enough and located so
that employees are not likely to come into accidental contact
with live parts or to bring conducting objects into contact
with them.
(c) Location on a suitable balcony, gallery, or platform
elevated and accessible only to qualified persons.
(d) Elevation of eight feet or more above the floor or other
working surface.
(2) In locations where electric equipment would be exposed to physical
damage, enclosures or guards must be arranged and be strong enough to
prevent damage.
(3) Entrances to rooms and other guarded locations containing exposed
live parts must be marked with conspicuous warning signs forbidding
unqualified persons to enter.
(4) Electrical repairs must be made only by qualified persons that
you authorize.
(5) Fuse handling equipment, insulated for the circuit voltage, must
be used to remove or install fuses when the fuse terminals are energized.
(6) Employees must be prohibited from working closely enough to an
electric power circuit to contact it unless the employee is protected
against electric shock.
Note: The circuit must be protected by deenergizing
the circuit and grounding it, by guarding it, by effective insulation,
or other means.
(7) In work areas where the exact location of underground electric
power lines is unknown, employees using jack-hammers, bars or other
hand tools that may contact a line must have insulated protective gloves.
(1) When parts are exposed, the minimum clearance for the workspace
must be at least six feet six inches high, or at least a radius of three
feet wide.
(2) There must be enough clearance to permit at least a 90° opening
of all doors or hinged panels.
Conductors must be spliced or joined with splicing devices suitable
for the use or by brazing, welding, or soldering with a fusible metal
or alloy. Soldered splices must first be spliced or joined so they are
mechanically and electrically secure without solder and then soldered.
(Rosin-core solder should be used instead of acid core solder when joining
electrical conductors.) All splices and joints and the free ends of
conductors must be covered with an insulation equivalent to that of
the conductors or with an insulating device suitable for the purpose.
WAC
296-307-36218 What protection must be provided against combustible
materials?
Parts of electric equipment that in ordinary operation produce arcs,
sparks, flames, or molten metal must be enclosed or separated and isolated
from all combustible material.
All electrical equipment in use must have the manufacturer's name,
trademark, or other descriptive marking of the organization responsible
for the product on the equipment. Other markings must be provided giving
voltage, current, wattage, or other ratings as necessary. The marking
must be durable enough to withstand the environment.
Each disconnecting means required by this part for motors and appliances
must be legibly marked to indicate its purpose, unless located and arranged
so the purpose is evident. Each service, feeder, and branch circuit,
at its disconnecting means or overcurrent device, must be legibly marked
to indicate its purpose, unless located and arranged so the purpose
is evident. These markings must be durable enough to withstand the environment
involved.
WAC
296-307-36227 What access and working space must be provided for
electrical equipment of 600 volts, nominal, or less?
Sufficient access and working space must be provided and maintained
about all electric equipment to permit ready and safe operation and
maintenance of such equipment.
(1) Unless otherwise indicated, the dimension of the working space
in the direction of access to live parts operating at 600 volts or less
and likely to require examination, adjustment, servicing, or maintenance
while alive must be at least that indicated in the table below. Also,
workspace must be at least 30 inches wide in front of the electric equipment.
Distances must be measured from the live parts if they are exposed,
or from the enclosure front or opening if the live parts are enclosed.
Concrete, brick, or tile walls are considered grounded. Working space
is not required behind assemblies such as dead-front switchboards or
motor control centers where there are no renewable or adjustable parts
such as fuses or switches on the back and where all connections are
accessible from other directions.
Working Clearances
Minimum clear distance for condition (ft.)
Nominal voltage to ground
(a)
(b)
(c)
0-150
13
13
3
151-600
13
3 1/2
4
Conditions:
(a) Exposed live parts on one side and no live or grounded
parts on the other side of the working space, or exposed
live parts on both sides guarded by suitable wood or other
insulating material. Insulated wire or insulated busbars
operating at 300 volts or less are not considered live parts.
(b) Exposed live parts on one side and grounded parts on
the other side.
(c) Exposed live parts on both sides of the workspace (not
guarded as in (a)) with the operator between.
(2) Working space required by this part must not be used for storage.
When normally enclosed live parts are exposed for inspection or servicing,
the working space, if in a passageway or general open space, must be
suitably guarded.
(3) At least one entrance of sufficient area must be provided to give
access to the working space about electric equipment.
(4) Where there are live parts normally exposed on the front of switchboards
or motor control centers, the working space in front of such equipment
must be at least 3 feet.
(5) All working spaces around service equipment, switchboards, panelboards,
and motor control centers installed indoors must be adequately lit.
(6) The minimum headroom of working spaces about service equipment,
switchboards, panelboards, or motor control centers must be 6 feet 3
inches.
“Motor control center” means an assembly of one or more enclosed
sections having a common power bus and principally containing motor
control units.
WAC
296-307-36230 What access and working space must be provided for
electrical equipment over 600 volts, nominal?
(1) Conductors and equipment used on circuits exceeding 600 volts,
nominal, must meet all requirements of WAC
296-307-36221 and the additional requirements of this section.
This section does not apply to equipment on the supply side of
the service conductors.
(2) Electrical installations in a vault, room, closet or area surrounded
by a wall, screen, or fence, with access controlled by lock and key
or other approved means, are considered accessible to qualified persons
only. A wall, screen, or fence less than 8 feet high is not considered
to prevent access unless it has other features that provide a degree
of isolation equivalent to an 8 foot fence. The entrances to all buildings,
rooms, or enclosures containing exposed live parts or exposed conductors
operating at over 600 volts, nominal, must be kept locked or under the
observation of a qualified person at all times.
(a) Electrical installations with exposed live parts must
be accessible to qualified persons only.
(b) Electrical installations that are open to unqualified
persons must be made with metal-enclosed equipment or enclosed
in a vault or in an area, with access controlled by a lock.
If metal-enclosed equipment is installed so that the bottom
of the enclosure is less than 8 feet above the floor, the
door or cover must be kept locked. Metal-enclosed switchgear,
unit substations, transformers, pull boxes, connection boxes,
and other similar associated equipment must be marked with
appropriate caution signs. If equipment is exposed to physical
damage from vehicular traffic, guards must be provided to
prevent damage. Ventilating or similar openings in metal-enclosed
equipment must be designed so that foreign objects inserted
through these openings will be deflected from energized parts.
(3) You must provide and maintain enough space around electric equipment
to permit ready and safe operation and maintenance of equipment. Where
energized parts are exposed, the minimum clear workspace must be at
least 6 feet 6 inches high (measured vertically from the floor or platform),
or less than 3 feet wide (measured parallel to the equipment). The depth
must meet the requirements of Table T. The workspace must be adequate
to permit at least a 90-degree opening of doors or hinged panels.
(a) The minimum clear working space in front of electric
equipment such as switchboards, control panels, switches,
circuit breakers, motor controllers, relays, and similar
equipment must be at least that specified in Table T unless
otherwise indicated. Distances must be measured from the
live parts if they are exposed, or from the enclosure front
or opening if the live parts are enclosed. However, working
space is not required in back of equipment such as deadfront
switchboards or control assemblies where there are no renewable
or adjustable parts (such as fuses or switches) on the back
and where all connections are accessible from another direction.
Where rear access is required to work on deenergized parts
on the back of enclosed equipment, a minimum working space
of 30 inches horizontally shall be provided.
Table T Minimum Depth of Clear Working Space in
Front of Electric Equipment
Conditions (ft.)
Nominal voltage to ground
(a)
(b)
(c)
601 to 2,500
3
4
5
2,501 to 9,000
4
5
6
9,001 to 25,000
5
6
9
25,001 to 75kV1
6
8
10
Above 75kV1
8
10
12
Note: Minimum depth of clear working
space in front of electric equipment with a nominal voltage
to ground above 25,000 volts may be the same as for 25,000
volts under conditions (a), (b) and (c) for installations
built prior to April 16, 1981.
Conditions:
(a) Exposed live parts on one side and no live or grounded
parts on the other side of the working space, or exposed
live parts on both sides guarded by suitable wood or
other insulating materials. Insulated wire or insulated
busbars operating at 300 volts or less are not considered
live parts.
(b) Exposed live parts on one side and grounded parts
on the other side. Concrete, brick, or tile walls will
be considered grounded surfaces.
(c) Exposed live parts on both sides of the workspace
(not guarded as in (a)) with the operator between.
(b) All working spaces around electric equipment must be
adequately lit. The lighting outlets shall be arranged so
that anyone changing lamps or making repairs on the lighting
system will not be endangered by live parts or other equipment.
The points of control must be located so that no one is likely
to come in contact with any live part or moving part of the
equipment while turning on the lights.
(c) Unguarded live parts above working space must be elevated
to at least the height specified below:
Elevation of Unguarded Energized Parts Above Working
Space
Nominal voltage between phases
Minimum elevation
601 to 7,500
8 feet 6 inches
7,501 to 35,000
9 feet
Over 35kV
9 feet + 0.37 inches per kV above 35kV
Note: Minimum elevation may be 8 feet
for installations built prior to April 16, 1981, if the nominal
voltage between phases is in the range of 601-6600 volts.
(4) Entrance and access to workspace must meet the following requirements:
(a) At least one entrance that is at least 24 inches wide
and 6 feet 6 inches high must be provided to give access
to the working space around electric equipment. On switchboard
and control panels over 48 inches wide, there must be one
entrance at each end of the board where practical. Where
bare energized parts at any voltage or insulated energized
parts above 600 volts are located adjacent to the entrance,
they must be suitably guarded.
(b) Permanent ladders or stairways must be provided to give
safe access to the working space around electric equipment
installed on platforms, balconies, mezzanine floors, or in
attic or roof rooms or spaces.
WAC
296-307-36403 How must flexible cords and cables be installed
and maintained?
(1) Extension cords used with portable electric tools and appliances
must be three wire and must be fitted with an approved grounding attachment
plug and receptacle providing ground continuity.
Exception: This does not apply to cords used with
portable tools and equipment provided by an approved system of double
insulation or its equivalent.
(2) Worn or frayed electric cables are prohibited.
WAC
296-307-36406 How must attachment plugs and receptacles be installed
and maintained?
(1) Attachment plugs used in work areas must be constructed so that
they will endure rough use and have a suitable cord grip to prevent
strain on the terminal screws.
(2) Attachment plugs must be approved grounding plugs.
(3) Receptacles for attachment plugs must have approved concealed contacts
with a contact for extending ground continuity. Receptacles must be
designed and constructed to ensure that the plug can be pulled out without
leaving any live parts exposed to accidental contact.
(4) Polarized attachment plugs, receptacles, and cord connectors must
be wired to maintain continuity.
(5) Polarized attachment plugs, receptacles, and cord connectors for
plugs and polarized plugs must have the terminal intended for connection
to the grounded (white) conductor identified by a metal coating that
is mostly white. If the terminal is not visible, its entrance hole must
be marked with the word “white,” or the color white.
(6) The terminal for the connection of the equipment grounding conductor
must be:
(a) A green colored, not easily removed terminal screw with
hexagonal head; or
(b) A green colored, hexagonal, not easily removed terminal
nut; or
(c) A green colored pressure wire connector.
If the terminal for the grounding conductor is not visible,
the conductor entrance hole must be marked with the word “green” or
the color green.
Note: Two-wire attachment plugs, unless
of the polarity type, need not have their terminals marked
for identification.
(7) Where different voltages, or types of current (A.C. or D.C.) are
to be supplied by portable cords, receptacles must be designed so that
attachment plugs used on the circuits are not interchangeable.
(8) Attachment plugs or other connectors supplying equipment at more
than 300 volts must be skirted or otherwise designed so that arcs are
confined.
WAC
296-307-36409 What must employees do when equipment causes electrical
shock?
Employees must report all shocks received from electrical equipment,
no matter how slight, immediately to you. The equipment causing the
shock must be checked and any necessary corrective action taken immediately.
WAC
296-307-36412 What grounding and bonding requirements apply to
equipment installation and maintenance?
(1) The path to ground must have enough carrying capacity to conduct
safely the currents likely to be imposed on it; and have low enough
impedance to limit the potential above ground and to result in the operation
of the overcurrent devices in the circuit.
(2) Driven rod electrodes must, where practical, have a resistance
to ground of a maximum of 25 ohms. Where the resistance is over 25 ohms,
two electrodes connected in parallel shall be used.
(3) Grounding circuits must be checked to ensure that the circuit between
the ground and the grounded power conductor has a resistance that is
low enough to permit sufficient current to flow to cause the fuse or
circuit breaker to interrupt the current.
(4) Conductors used for bonding and grounding equipment must be large
enough to carry the anticipated current.
WAC
296-307-36418 What requirements apply to identification and load
rating of electrical equipment?
(1) Name plates, rating data, and marks of identification on electrical
equipment and electrically operated machines must not be removed, defaced
or obliterated.
(2) In existing installations, no changes in circuit protection must
be made to increase the load beyond the load rating of the circuit wiring,
as specified in the National Electrical Code, NFPA 70-1973; ANSI C1-1972,
Article 310.
(3) Tampering with, bridging, or using oversize fuses is prohibited.
If fuses blow repeatedly, employees must immediately report the trouble
to you or to an authorized electrician.
(4) Attempting to start electric motors that kick out repeatedly is
prohibited.
(1) Cabinets, cutout boxes, fittings, boxes, and panelboard enclosures
in damp or wet locations must be installed to prevent moisture or water
from entering and accumulating within the enclosures. In wet locations
the enclosures must be weatherproof.
(2) Switches, circuit breakers, and switchboards installed in wet locations
must be enclosed in weatherproof enclosures.
WAC
296-307-36603 How must grounded and grounding conductors be used
and identified?
(1) A conductor used as a grounded conductor must be identified separately
from all other conductors. A conductor used as an equipment grounding
conductor must be identified separately from all other conductors.
(2) A grounded conductor must not be attached to any terminal or lead
to reverse the designated polarity.
(3) Using a grounding terminal or grounding-type device on a receptacle,
cord connector, or attachment plug for anything other than grounding
is prohibited.
This section applies to branch circuit, feeder, and service conductors
rated 600 volts, nominal, or less and run outdoors as open conductors.
(1) Conductors supported on poles must provide a horizontal climbing
space of at least the following:
(a) For power conductors below communication conductors,
30 inches.
(b) For power conductors alone or above communication conductors:
300 volts or less, 24 inches;
More than 300 volts, 30 inches.
(c) For communication conductors below power conductors
with power conductors of:
300 volts or less, 24 inches;
More than 300 volts, 30 inches.
(2) Open conductors must provide at least the following minimum clearances:
(a) 10 feet, above finished grade, sidewalks, or from any
platform or projection from which they might be reached;
(b) 12 feet, over areas subject to vehicular traffic other
than truck traffic;
(c) 15 feet, over areas that are subject to truck traffic;
except
(d) 18 feet, over public streets, alleys, roads, and driveways.
(3) Conductors must have a clearance of at least 3 feet from windows,
doors, porches, fire escapes, or similar locations. Conductors run above
the top level of a window are considered to be out of reach from that
window and, therefore, do not have to be 3 feet away.
(4) Conductors must have a clearance of at least 8 feet from the highest
point of roofs they pass over.
Exceptions:
(a) Where the voltage between conductors
is 300 volts or less and the roof has a slope of at least
4 inches in 12, the clearance from the roofs must be at least
3 feet; or
(b) Where the voltage between conductors
is 300 volts or less, the conductors do not pass over more
than 4 feet of the overhang portion of the roof, and they
are terminated at a through-the-roof raceway or approved
support, the clearance from the roofs must be at least 18
inches.
(5) Lamps for outdoor lighting must be located below all live conductors,
transformers, or other electric equipment, unless such equipment is
controlled by a disconnecting means that can be locked in the open position
or unless adequate clearances or other safeguards are provided for relamping
operations.
WAC
296-307-36612 What design and protection requirements apply to
service-entrances?
(1) Disconnecting means for service-entrances must meet the following
requirements:
(a) Means must be provided to disconnect all conductors
in a building or other structure from the service-entrance
conductors. The disconnecting means must plainly indicate
whether it is in the open or closed position and must be
installed at a readily accessible location nearest the point
of entrance of the service-entrance conductors.
(b) Each service disconnecting means must disconnect all
ungrounded conductors at the same time.
(2) The following additional requirements apply to services over 600
volts, nominal.
(a) Service-entrance conductors installed as open wires
must be guarded to make them accessible only to qualified
persons.
(b) Signs warning of high voltage must be posted where other
than qualified employees might come in contact with live
parts.
(1) The following requirements apply to overcurrent protection of circuits
rated 600 volts, nominal, or less.
(a) Conductors and equipment must be protected from overcurrent
according to their ability to safely conduct current.
(b) Except for motor running overload protection, overcurrent
devices must not interrupt the continuity of the grounded
conductor unless all conductors of the circuit are opened
at the same time.
(c) Except for service fuses, all cartridge fuses that are
accessible to other than qualified persons and all fuses
and thermal cutouts on circuits over 150 volts to ground
must have disconnecting means. This disconnecting means must
be installed so that the fuse or thermal cutout can be disconnected
from its supply without disrupting service to equipment and
circuits unrelated to those protected by the overcurrent
device.
(d) Overcurrent devices must be readily accessible to each
employee or authorized building management personnel. These
overcurrent devices must be located where they will be protected
against physical damage and away from easily ignitable material.
(e) Fuses and circuit breakers must be located or shielded
so that employees will not be burned or otherwise injured
by their operation.
(f) Circuit breakers must meet the following requirements:
(i) Circuit breakers must clearly indicate whether they
are in the open (off) or closed (on) position.
(ii) Where circuit breaker handles on switchboards are
operated vertically rather than horizontally or rotationally,
the up position of the handle must be the closed (on) position.
(iii) If used as switches in 120-volt, fluorescent lighting
circuits, circuit breakers must be approved for the purpose
and marked “SWD.”
(2) Feeders and branch circuits over 600 volts, nominal, must have
short-circuit protection.
The following systems that supply premises wiring must be grounded:
(1) All 3-wire DC systems must have their neutral conductor grounded.
(2) Two-wire DC systems operating at 50-300 volts between conductors
must be grounded.
Exceptions: This requirement does not apply if:
(a) They supply only industrial equipment in limited areas
and are equipped with a ground detector; or
(b) They are rectifier-derived from an AC system that meets
the requirements of subsections (3), (4), and (5) of this
section; or
(c) They are fire-protective signaling circuits with a maximum
current of 0.030 amperes.
(3) AC circuits of less than 50 volts must be grounded if they are
installed as overhead conductors outside of buildings or if they are
supplied by transformers and the transformer primary supply system is
ungrounded or exceeds 150 volts to ground.
(4) AC systems of 50-1000 volts must be grounded under any of the following
conditions:
(a) If the system can be grounded so that the maximum voltage
to ground on the ungrounded conductors is a maximum of 150
volts;
(b) If the system is nominally rated 480Y/277 volt, 3-phase,
4-wire in which the neutral is used as a circuit conductor;
(c) If the system is nominally rated 240/120 volt, 3-phase,
4-wire in which the midpoint of one phase is used as a circuit
conductor; or
(d) If a service conductor is uninsulated.
(5) Exceptions: AC systems of 50-1000 volts are not required to be
grounded under any of the following conditions:
(a) If the system is used exclusively to supply industrial
electric furnaces for melting, refining, tempering, and the
like.
(b) If the system is separately derived and is used exclusively
for rectifiers supplying only adjustable speed industrial
drives.
(c) If the system is separately derived and is supplied
by a transformer that has a primary voltage rating less than
1000 volts, if all of the following conditions are met:
(i) The system is used exclusively for control circuits;
(ii) The conditions of maintenance and supervision ensure
that only qualified persons will service the installation;
(iii) Continuity of control power is required; and
(iv) Ground detectors are installed on the control system.
WAC
296-307-36624 What general requirements apply to grounding conductors?
(1) For a grounded system, a grounding electrode conductor must be
used to connect both the equipment grounding conductor and the grounded
circuit conductor to the grounding electrode. Both the equipment grounding
conductor and the grounding electrode conductor must be connected to
the grounded circuit conductor on the supply side of the service disconnecting
means, or on the supply side of the system disconnecting means or overcurrent
devices if the system is separately derived.
(2) For an ungrounded service-supplied system, the equipment grounding
conductor must be connected to the grounding electrode conductor at
the service equipment. For an ungrounded separately derived system,
the equipment grounding conductor must be connected to the grounding
electrode conductor at, or ahead of, the system disconnecting means
or overcurrent devices.
(3) On extensions of existing branch circuits that do not have an equipment
grounding conductor, grounding-type receptacles may be grounded to a
grounded cold water pipe near the equipment.
WAC
296-307-36630 What supports, enclosures, and equipment must be
grounded?
(1) Metal cable trays, metal raceways, and metal enclosures for conductors
must be grounded.
Exceptions:
(a) Metal enclosures such as sleeves
that are used to protect cable assemblies from physical damage
need not be grounded; or
(b) Metal enclosures for conductors
added to existing installations of open wire, knob-and-tube
wiring, and nonmetallic-sheathed cable need not be grounded
if all of the following conditions are met:
(i) Runs are less than 25 feet;
(ii) Enclosures are free from probable
contact with ground, grounded metal, metal laths, or other
conductive materials; and
(iii) Enclosures are guarded against
employee contact.
(2) Metal enclosures for service equipment must be grounded.
(3) Frames of electric ranges, wall-mounted ovens, counter-mounted
cooking units, clothes dryers, and metal outlet or junction boxes that
are part of the circuit for these appliances must be grounded.
(4) Exposed noncurrent-carrying metal parts of fixed equipment that
may become energized must be grounded under any of the following conditions:
(a) If within 8 feet vertically or 5 feet horizontally of
ground or grounded metal objects and subject to employee
contact;
(b) If located in a wet or damp location and not isolated;
(c) If in electrical contact with metal;
(d) If in a hazardous (classified) location;
(e) If supplied by a metal-clad, metal-sheathed, or grounded
metal raceway wiring method;
(f) If equipment operates with any terminal at over 150
volts to the ground; however, the following need not be grounded:
(i) Enclosures for switches or circuit breakers used for
other than service equipment and accessible to qualified
persons only;
(ii) Metal frames of electrically heated appliances that
are permanently and effectively insulated from ground;
and
(iii) The cases of distribution apparatus such as transformers
and capacitors mounted on wooden poles that are over 8
feet above ground or grade level.
(5) Under any of the conditions below, exposed noncurrent-carrying
metal parts of cord-connected and plug-connected equipment that may
become energized must be grounded.
(a) When equipment is in hazardous (classified) locations.
(b) When equipment is operated at over 150 volts to ground.
Exception: Guarded motors and metal
frames of electrically heated appliances need not be grounded
if the appliance frames are permanently and effectively insulated
from ground.
(c) When equipment is one of the following:
Refrigerators, freezers, and air conditioners;
Clothes-washing, clothes-drying and dishwashing machines,
sump pumps, and electrical aquarium equipment;
Hand-held motor-operated tools;
The following motor-operated appliances: Hedge clippers,
lawn mowers, snow blowers, and wet scrubbers;
Cord-connected and plug-connected appliances used in
damp or wet locations or by employees standing on the
ground or on metal floors or working inside of metal
tanks or boilers;
Tools likely to be used in wet and conductive locations;
and
Portable hand lamps.
Tools likely to be used in wet and conductive locations
need not be grounded if supplied through an isolating transformer
with an ungrounded secondary of a maximum of 50 volts. Listed
or labeled portable tools and appliances protected by an
approved system of double insulation, or its equivalent,
need not be grounded. The equipment must be distinctively
marked to indicate that the tool or appliance uses an approved
system of double insulation.
(6) The metal parts of the following nonelectrical equipment must be
grounded: Frames and tracks of electrically operated cranes; frames
of nonelectrically driven elevator cars to which electric conductors
are attached; hand operated metal shifting ropes or cables of electric
elevators, and metal partitions, grill work, and other metal enclosures
around equipment of over 750 volts between conductors.
(1) Noncurrent-carrying metal parts of fixed equipment, if required
to be grounded by this section, must be grounded by an equipment grounding
conductor that is contained within the same raceway, cable, or cord,
or runs with or encloses the circuit conductors. For DC circuits only,
the equipment grounding conductor may be run separately from the circuit
conductors.
(2) Electric equipment is considered grounded if it is secured to,
and in electrical contact with, a metal rack or structure that is provided
for its support and the metal rack or structure is grounded as described
above.
For installations made before May 30, 1982, electric equipment is also
considered grounded if it is secured to, and in metallic contact with,
the grounded structural metal frame of a building. Metal car frames
supported by metal hoisting cables attached to or running over metal
sheaves or drums of grounded elevator machines are also considered grounded.
Grounded high voltage (1000 volts or more) systems and circuits
must meet all requirements of WAC
296-307-366 and the additional requirements of this section.
(1) Systems supplying portable or mobile high voltage equipment, other
than substations installed on a temporary basis, must meet the following
requirements:
(a) Portable and mobile high voltage equipment must be supplied
from a system having its neutral grounded through an impedance.
If a delta-connected high voltage system is used to supply
the equipment, a system neutral must be derived.
(b) Exposed noncurrent-carrying metal parts of portable
and mobile equipment must be connected by an equipment grounding
conductor to the point at which the system neutral impedance
is grounded.
(c) Ground-fault detection and relaying must be provided
to automatically deenergize any high voltage system component
that has developed a ground fault. The continuity of the
equipment grounding conductor must be continuously monitored
to deenergize automatically the high voltage feeder to the
portable equipment on loss of continuity of the equipment
grounding conductor.
(d) The grounding electrode to which the portable or mobile
equipment system neutral impedance is connected must be isolated
from and separated in the ground by at least 20 feet from
any other system or equipment grounding electrode. There
must be no direct connection between the grounding electrodes,
such as buried pipe, fence, etc.
(2) All noncurrent-carrying metal parts of portable equipment and fixed
equipment including their associated fences, housings, enclosures, and
supporting structures shall be grounded. However, equipment that is
guarded by location and isolated from ground need not be grounded. Additionally,
pole-mounted distribution apparatus over 8 feet above ground or grade
level need not be grounded.
WAC
296-307-36806 What wiring methods must be used for temporary wiring?
Temporary electrical power and lighting wiring methods may be of a
class less than would be required for a permanent installation. All
requirements for permanent wiring apply to temporary wiring installations,
except as indicated in this section.
(1) Temporary electrical power and lighting installations 600 volts,
nominal, or less must only be used:
(a) During and for remodeling, maintenance, repair, or demolition
of buildings, structures, or equipment, and similar activities;
(b) For experimental or development work; and
(c) For a maximum of 90 days for Christmas lighting and
similar purposes.
(2) Temporary wiring over 600 volts, nominal, must only be used during
periods of tests, experiments, or emergencies.
(3) General requirements for temporary wiring.
(a) Working spaces, walkways, and similar locations must
be kept clear of power cords.
(b) All temporary wiring must be grounded. (See NFPA 70
Art. 250.)
(c) All wiring equipment must be maintained as vapor-tight,
dust-tight, or fiber-tight as their approval requires. There
must be no loose or missing screws, gaskets, threaded connections,
or other conditions that impair the required tightness.
(d) Take precautions to make necessary open wiring accessible
only to authorized personnel.
(e) Feeders must originate in an approved distribution center.
The conductors must be run as multiconductor cord or cable
assemblies, or, where not subject to physical damage, they
may be run as open conductors on insulators not more than
10 feet apart.
(f) Branch circuits must originate in an approved power
outlet or panelboard. Conductors must be multiconductor cord
or cable assemblies or open conductors. If run as open conductors
they must be fastened at ceiling height every 10 feet. A
branch-circuit conductor must not be laid on the floor. Each
branch circuit that supplies receptacles or fixed equipment
must have a separate equipment grounding conductor if run
as open conductors.
(g) Receptacles must be of the grounding type. Unless installed
in a complete metallic raceway, each branch circuit must
have a separate equipment grounding conductor and all receptacles
must be electrically connected to the grounding conductor.
(h) A bare conductor or an earth return must not be used
to wire any temporary circuit.
(i) Suitable disconnecting switches or plug connectors must
be installed to permit the disconnection of all ungrounded
conductors of each temporary circuit.
(j) Lamps for general illumination must be protected from
accidental contact or breakage. Lamps must be elevated at
least 7 feet from normal working surface or by a suitable
fixture or lampholder with a guard.
(k) Flexible cords and cables must be protected from accidental
damage. Sharp corners and projections must be avoided. Where
passing through doorways or other pinch points, flexible
cords and cables must be protected to avoid damage.
(4) General requirements for temporary lighting.
(a) Temporary lights must have guards to prevent accidental
contact with the bulb.
Note: Guards are not required when
the entire bulb is below the rim and completely surrounded
and protected by the reflector.
(b) Temporary lights must have heavy duty electric cords
with connections and insulation maintained in safe condition.
(c) Temporary lights must not be suspended by their electric
cords unless cords and lights are designed for suspension.
(d) Brass shell, paper-lined lamp holders are prohibited.
(e) Portable extension lamps used where flammable vapors
or gases, combustible dusts, or easily ignitable fibers or
flyings are present, must be specifically approved as complete
assemblies for the type of hazard.
(g) Multiconductor service-entrance cable (Type SE or USE);
(h) Multiconductor underground feeder and branch-circuit
cable (Type UF);
(i) Power and control tray cable (Type TC);
(j) Other factory-assembled, multiconductor control, signal,
or power cables that are specifically approved for installation
in cable trays; or
(k) Any approved conduit or raceway with its contained conductors.
(2) In industrial establishments only, where conditions of maintenance
and supervision ensure that only qualified persons will service the
installed cable tray system, the following cables may also be installed
in ladder, ventilated trough, or 4 inch ventilated channel-type cable
trays:
Single conductor cables that are 250 MCM or larger and are Types RHH,
RHW, MV, USE, or THW, and other 250 MCM or larger single conductor cables
if specifically approved for installation in cable trays. Where exposed
to direct rays of the sun, cables must be sunlight-resistant.
(3) Cable trays in hazardous (classified) locations must contain only
the cable types permitted in such locations.
Exception: Cable tray systems must not be used
in hoistways or where subjected to severe physical damage.
WAC
296-307-36812 What requirements apply to open wiring on insulators?
(1) Open wiring on insulators is only permitted on systems of 600 volts,
nominal, or less for industrial or agricultural establishments and for
services.
(2) Conductors must be rigidly supported on noncombustible, nonabsorbent
insulating materials and must not contact any other objects.
(3) In dry locations with no exposure to severe physical damage, conductors
may be separately enclosed in flexible nonmetallic tubing. The tubing
must be in continuous lengths a maximum of 15 feet and secured to the
surface by straps at maximum intervals of 4 feet 6 inches.
(4) Open conductors must be separated from contact with walls, floors,
and wood cross members, or partitions through which they pass by tubes
or bushings of noncombustible, nonabsorbent insulating material. If
the bushing is shorter than the hole, a waterproof sleeve of nonconductive
material must be inserted in the hole and an insulating bushing slipped
into the sleeve at each end to keep the conductors completely out of
contact with the sleeve. Each conductor must be carried through a separate
tube or sleeve.
(5) Conductors within 7 feet of the floor are considered exposed to
physical damage. Where open conductors cross ceiling joints and wall
studs and are exposed to physical damage, they must be protected.
WAC
296-307-36815 What wiring requirements apply to cabinets, boxes,
and fittings?
(1) Conductors entering boxes, cabinets, or fittings must be protected
from abrasion, and openings through which conductors enter must be closed.
Unused openings in cabinets, boxes, and fittings must also be closed.
(2) All pull boxes, junction boxes, and fittings must have covers approved
for the purpose. All metal covers must be grounded. In completed installations
each outlet box must have a cover, faceplate, or fixtu
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