WAC
296-155-449 Wiring methods, components, and equipment for
general use.
(1) Wiring methods. The provisions of this subsection do not
apply to conductors which form an integral part of equipment such
as motors, controllers, motor control centers and like equipment.
(a) General requirements.
(i) Electrical continuity of metal raceways and enclosures.
Metal raceways, cable armor, and other metal enclosures for
conductors shall be metallically joined together into a continuous
electric conductor and shall be so connected to all boxes,
fittings, and cabinets as to provide effective electrical
continuity.
(ii) Wiring in ducts. No wiring systems of any type shall
be installed in ducts used to transport dust, loose stock
or flammable vapors. No wiring system of any type shall be
installed in any duct used for vapor removal or in any shaft
containing only such ducts.
(iii) Receptacles for attachment plugs shall be approved,
concealed contact type with a contact for extending ground
continuity and shall be so designed and constructed that the
plug may be pulled out without leaving any live parts exposed
to accidental contact. All temporary outlet boxes shall be
of a type suitable for use in wet or damp locations.
(iv) Attachment plugs or other connectors supplying equipment
at more than 300 volts shall be of the skirted type or otherwise
so designed that arcs will be confined.
(b) Temporary wiring.
(i) Scope. The provisions of (b) of this subsection apply
to temporary electrical power and lighting wiring methods
which may be of a class less than would be required for a
permanent installation. Except as specifically modified in
(b) of this subsection, all other requirements of this part
for permanent wiring shall apply to temporary wiring installations.
Temporary wiring shall be removed immediately upon completion
of construction or the purpose for which the wiring was installed.
(ii) General requirements for temporary wiring.
(A) Feeders shall originate in a distribution center. The
conductors shall be run as multiconductor cord or cable
assemblies or within raceways; or, where not subject to
physical damage, they may be run as open conductors on insulators
not more than 10 feet (3.05 m) apart.
(B) Branch circuits shall originate in a power outlet or
panelboard. Conductors shall be run as multiconductor cord
or cable assemblies or open conductors, or shall be run
in raceways. All conductors shall be protected by overcurrent
devices at their ampacity. Runs of open conductors shall
be located where the conductors will not be subject to physical
damage, and the conductors shall be fastened at intervals
not exceeding 10 feet (3.05 m). No branch-circuit conductors
shall be laid on the floor. Each branch circuit that supplies
receptacles or fixed equipment shall contain a separate
equipment grounding conductor if the branch circuit is run
as open conductors.
(C) Receptacles shall be of the grounding type. Unless
installed in a complete metallic raceway, each branch circuit
shall contain a separate equipment grounding conductor,
and all receptacles shall be electrically connected to the
grounding conductor. Receptacles for uses other than temporary
lighting shall not be installed on branch circuits which
supply temporary lighting. Receptacles shall not be connected
to the same ungrounded conductor of multiwire circuits which
supply temporary lighting.
(D) Disconnecting switches or plug connectors shall be
installed to permit the disconnection of all ungrounded
conductors of each temporary circuit.
(E) All lamps for general illumination shall be protected
from accidental contact or breakage. Metal-case sockets
shall be grounded.
(F) Temporary lights shall be equipped with hard usage
(S or SJ types) electric cords with connections and insulation
maintained in safe condition. “Brewery” cord
(type CBO or NB) may be substituted for hard usage cord
provided it is protected from physical damages. Temporary
lights shall not be suspended by their electric cords unless
cords and lights are designed for this means of suspension.
Splices shall retain the insulation, outer sheath properties,
flexibility, and usage characteristics of the cord being
spliced.
When pin-type connectors or lampholders are utilized, the
area of perforations caused by lampholder removal shall
be restored to the insulation capabilities of the cord.
(G) Portable electric lighting used in wet and/or other
conductive locations, as for example, drums, tanks, and
vessels, shall be operated at 12 volts or less. However,
120-volt lights may be used if protected by a ground-fault
circuit interrupter.
(H) A box shall be used wherever a change is made to a
raceway system or a cable system which is metal clad or
metal sheathed.
(I) Flexible cords and cables shall be protected from damage.
Sharp corners and projections shall be avoided. Flexible
cords and cables may pass through doorways or other pinch
points, if protection is provided to avoid damage.
(J) Extension cord sets used with portable electric tools
and appliances shall be of three-wire type and shall be
designed for hard or extra-hard usage. Flexible cords used
with temporary and portable lights shall be designed for
hard or extra-hard usage.
Note: The National Electrical Code, ANSI/NFPA
70, in Article 400, Table 400-4, lists various types of flexible
cords, some of which are noted as being designed for hard or extra-hard
usage. Examples of these types of flexible cords include hard
service cord (types S, ST, SO, STO) and junior hard service cord
(types SJ, SJO, SJT, SJTO).
(iii) Guarding. For temporary wiring over 600 volts, nominal,
fencing, barriers, or other effective means shall be provided
to prevent access of other than authorized and qualified personnel.
(2) Cabinets, boxes, and fittings.
(a) Conductors entering boxes, cabinets, or fittings. Conductors
entering boxes, cabinets, or fittings shall be protected from
abrasion, and openings through which conductors enter shall
be effectively closed. Unused openings in cabinets, boxes, and
fittings shall also be effectively closed.
(b) Covers and canopies. All pull boxes, junction boxes, and
fittings shall be provided with covers. If metal covers are
used, they shall be grounded. In energized installations each
outlet box shall have a cover, faceplate, or fixture canopy.
Covers of outlet boxes having holes through which flexible cord
pendants pass shall be provided with bushings designed for the
purpose or shall have smooth, well-rounded surfaces on which
the cords may bear.
(c) Pull and junction boxes for systems over 600 volts, nominal.
In addition to other requirements in this section for pull and
junction boxes, the following shall apply to these boxes for
systems over 600 volts, nominal:
(i) Complete enclosure. Boxes shall provide a complete enclosure
for the contained conductors or cables.
(ii) Covers. Boxes shall be closed by covers securely fastened
in place. Underground box covers that weigh over 100 pounds
(43.6 kg) meet this requirement. Covers for boxes shall be
permanently marked “HIGH VOLTAGE.” The marking
shall be on the outside of the box cover and shall be readily
visible and legible.
(3) Knife switches. Single-throw knife switches shall be so connected
that the blades are dead when the switch is in the open position.
Single-throw knife switches shall be so placed that gravity will
not tend to close them. Single-throw knife switches approved for
use in the inverted position shall be provided with a locking
device that will ensure that the blades remain in the open position
when so set. Double-throw knife switches may be mounted so that
the throw will be either vertical or horizontal. However, if the
throw is vertical, a locking device shall be provided to ensure
that the blades remain in the open position when so set.
(4) Switchboards and panelboards. Switchboards that have any
exposed live parts shall be located in permanently dry locations
and accessible only to qualified persons. Panelboards shall be
mounted in cabinets, cutout boxes, or enclosures designed for
the purpose and shall be dead front. However, panelboards other
than the dead front externally-operable type are permitted where
accessible only to qualified persons. Exposed blades of knife
switches shall be dead when open.
(5) Enclosures for damp or wet locations.
(a) Cabinets, fittings, and boxes. Cabinets, cutout boxes,
fittings, boxes, and panelboard enclosures in damp or wet locations
shall be installed so as to prevent moisture or water from entering
and accumulating within the enclosures. In wet locations the
enclosures shall be weatherproof.
(b) Switches and circuit breakers. Switches, circuit breakers,
and switchboards installed in wet locations shall be enclosed
in weatherproof enclosures.
(6) Conductors for general wiring. All conductors used for general
wiring shall be insulated unless otherwise permitted in this part.
The conductor insulation shall be of a type that is suitable for
the voltage, operating temperature, and location of use. Insulated
conductors shall be distinguishable by appropriate color or other
means as being grounded conductors, ungrounded conductors, or
equipment grounding conductors.
(7) Flexible cords and cables.
(a) Use of flexible cords and cables.
(i) Permitted uses. Flexible cords and cables shall be suitable
for conditions of use and location. Flexible cords and cables
shall be used only for:
(A) Pendants;
(B) Wiring of fixtures;
(C) Connection of portable lamps or appliances;
(D) Elevator cables;
(E) Wiring of cranes and hoists;
(F) Connection of stationary equipment to facilitate their
frequent interchange;
(G) Prevention of the transmission of noise or vibration;
or
(H) Appliances where the fastening means and mechanical
connections are designed to permit removal for maintenance
and repair.
(ii) Attachment plugs for cords. If used as permitted in
(a)(i)(C), (F), or (H) of this subsection, the flexible cord
shall be equipped with an attachment plug and shall be energized
from a receptacle outlet.
(iii) Prohibited uses. Unless necessary for a use permitted
in (a)(i) of this subsection, flexible cords and cables shall
not be used:
(A) As a substitute for the fixed wiring of a structure;
(B) Where run through holes in walls, ceilings, or floors;
(C) Where run through doorways, windows, or similar openings,
except as permitted in subsection (1)(b)(ii)(I) of this
section;
(D) Where attached to building surfaces; or
(E) Where concealed behind building walls, ceilings, or
floors.
(b) Identification, splices, and terminations.
(i) Identification. A conductor of a flexible cord or cable
that is used as a grounded conductor or an equipment grounding
conductor shall be distinguishable from other conductors.
(ii) Marking. Type SJ, SJO, SJT, SJTO, S, SO, ST, and STO
cords shall not be used unless durably marked on the surface
with the type designation, size, and number of conductors.
(iii) Splices. Flexible cords shall be used only in continuous
lengths without splice or tap. Hard service flexible cords
No. 12 or larger may be repaired if spliced so that the splice
retains the insulation, outer sheath properties, and usage
characteristics of the cord being spliced.
(iv) Strain relief. Flexible cords shall be connected to
devices and fittings so that strain relief is provided which
will prevent pull from being directly transmitted to joints
or terminal screws.
(v) Cords passing through holes. Flexible cords and cables
shall be protected by bushings or fittings where passing through
holes in covers, outlet boxes, or similar enclosures.
(vi) Trailing cables shall be protected from damage.
(vii) Cord and cable passing through work areas shall be
covered or elevated to protect it from damage which would
create a hazard to employees.
(8) Portable cables over 600 volts, nominal. Multi-conductor
portable cable for use in supplying power to portable or mobile
equipment at over 600 volts, nominal, shall consist of No. 8 or
larger conductors employing flexible stranding. Cables operated
at over 2000 volts shall be shielded for the purpose of confining
the voltage stresses to the insulation. Grounding conductors shall
be provided. Connectors for these cables shall be of a locking
type with provisions to prevent their opening or closing while
energized. Strain relief shall be provided at connections and
terminations. Portable cables shall not be operated with splices
unless the splices are of the permanent molded, vulcanized, or
other equivalent type. Termination enclosures shall be marked
with a high voltage hazard warning, and terminations shall be
accessible only to authorized and qualified personnel.
(9) Fixture wires.
(a) General. Fixture wires shall be suitable for the voltage,
temperature, and location of use. A fixture wire which is used
as a grounded conductor shall be identified.
(b) Uses permitted. Fixture wires may be used:
(i) For installation in lighting, fixtures and in similar
equipment where enclosed or protected and not subject to bending
or twisting in use; or
(ii) For connecting lighting fixtures to the branch-circuit
conductors supplying the fixtures.
(c) Uses not permitted. Fixture wires shall not be used as
branch-circuit conductors except as permitted for Class 1 power-limited
circuits.
(10) Equipment for general use.
(a) Lighting fixtures, lampholders, lamps, and receptacles.
(i) Live parts. Fixtures, lampholders, lamps, rosettes, and
receptacles shall have no live parts normally exposed to employee
contact. However, rosettes and cleat-type lampholders and
receptacles located at least 8 feet (2.44 m) above the floor
may have exposed parts.
(ii) Support. Fixtures, lampholders, rosettes, and receptacles
shall be securely supported. A fixture that weighs more than
6 pounds (2.72 kg) or exceeds 16 inches (406 mm) in any dimension
shall not be supported by the screw shell of a lampholder.
(iii) Portable lamps. Portable lamps shall be wired with
flexible cord and an attachment plug of the polarized or grounding
type. If the portable lamp uses an Edison-based lampholder,
the grounded conductor shall be identified and attached to
the screw shell and the identified blade of the attachment
plug. In addition, portable handlamps shall comply with the
following:
(A) Metal shell, paperlined lampholders shall not be used;
(B) Handlamps shall be equipped with a handle of molded
composition or other insulating material;
(C) Handlamps shall be equipped with a substantial guard
attached to the lampholder or handle;
(D) Metallic guards shall be grounded by the means of an
equipment grounding conductor run within the power supply
cord.
(iv) Lampholders. Lampholders of the screw-shell type shall
be installed for use as lampholders only. Lampholders installed
in wet or damp locations shall be of the weatherproof type.
(v) Fixtures. Fixtures installed in wet or damp locations
shall be identified for the purpose and shall be installed
so that water cannot enter or accumulate in wireways, lampholders,
or other electrical parts.
(b) Receptacles, cord connectors, and attachment plugs (caps).
(i) Configuration. Receptacles, cord connectors, and attachment
plugs shall be constructed so that no receptacle or cord connector
will accept an attachment plug with a different voltage or
current rating than that for which the device is intended.
However, a 20-ampere T-slot receptacle or cord connector may
accept a 15-ampere attachment plug of the same voltage rating.
Receptacles connected to circuits having different voltages,
frequencies, or types of current (AC or DC) on the same premises
shall be of such design that the attachment plugs used on
these circuits are not interchangeable.
(ii) Damp and wet locations. A receptacle installed in a
wet or damp location shall be designed for the location.
(c) Appliances.
(i) Live parts. Appliances, other than those in which the
current-carrying parts at high temperatures are necessarily
exposed, shall have no live parts normally exposed to employee
contact.
(ii) Disconnecting means. A means shall be provided to disconnect
each appliance.
(iii) Rating. Each appliance shall be marked with its rating
in volts and amperes or volts and watts.
(d) Motors. This subdivision applies to motors, motor circuits,
and controllers.
(i) In sight from. If specified that one piece of equipment
shall be “in sight from” another piece of equipment,
one shall be visible and not more than 50 feet (15.2 m) from
the other.
(ii) Disconnecting means.
(A) A disconnecting means shall be located in sight from
the controller location. The controller disconnecting means
for motor branch circuits over 600 volts, nominal, may be
out of sight of the controller, if the controller is marked
with a warning label giving the location and identification
of the disconnecting means which is to be locked in the
open position.
(B) The disconnecting means shall disconnect the motor
and the controller from all ungrounded supply conductors
and shall be so designed that no pole can be operated independently.
(C) If a motor and the driven machinery are not in sight
from the controller location, the installation shall comply
with one of the following conditions:
(I) The controller disconnecting means shall be capable
of being locked in the open position.
(II) A manually operable switch that will disconnect
the motor from its source of supply shall be placed in
sight from the motor location.
(D) The disconnecting means shall plainly indicate whether
it is in the open (off) or closed (on) position.
(E) The disconnecting means shall be readily accessible.
If more than one disconnect is provided for the same equipment,
only one need be readily accessible.
(F) An individual disconnecting means shall be provided
for each motor, but a single disconnecting means may be
used for a group of motors under any one of the following
conditions:
(I) If a number of motors drive special parts of a single
machine or piece of apparatus, such as a metal or woodworking
machine, crane, or hoist;
(II) If a group of motors is under the protection of
one set of branch-circuit protective devices; or
(III) If a group of motors is in a single room in sight
from the location of the disconnecting means.
(iii) Motor overload, short-circuit, and ground-fault protection.
Motors, motor-control apparatus, and motor branch-circuit
conductors shall be protected against overheating due to motor
overloads or failure to start, and against short-circuits
or ground faults. These provisions do not require overload
protection that will stop a motor where a shutdown is likely
to introduce additional or increased hazards, as in the case
of fire pumps, or where continued operation of a motor is
necessary for a safe shutdown of equipment or process and
motor overload sensing devices are connected to a supervised
alarm.
(iv) Protection of live parts-all voltages.
(A) Stationary motors having commutators, collectors, and
brush rigging located inside of motor end brackets and not
conductively connected to supply circuits operating at more
than 150 volts to ground need not have such parts guarded.
Exposed live parts of motors and controllers operating at
50 volts or more between terminals shall be guarded against
accidental contact by any of the following:
(I) By installation in a room or enclosure that is accessible
only to qualified persons;
(II) By installation on a balcony, gallery, or platform,
so elevated and arranged as to exclude unqualified persons;
or
(III) By elevation 8 feet (2.44 m) or more above the
floor.
(B) Where live parts of motors or controllers operating
at over 150 volts to ground are guarded against accidental
contact only by location, and where adjustment or other
attendance may be necessary during the operation of the
apparatus, insulating mats or platforms shall be provided
so that the attendant cannot readily touch live parts unless
standing on the mats or platforms.
(e) Transformers.
(i) Application. The following subsections cover the installation
of all transformers, except:
(A) Current transformers;
(B) Dry-type transformers installed as a component part
of other apparatus;
(C) Transformers which are an integral part of an x-ray,
high frequency, or electrostatic-coating apparatus;
(D) Transformers used with Class 2 and Class 3 circuits,
sign and outline lighting, electric discharge lighting,
and power-limited fire-protective signaling circuits.
(ii) Operating voltage. The operating voltage of exposed
live parts of transformer installations shall be indicated
by warning signs or visible markings on the equipment or structure.
(iii) Transformers over 35 kV. Dry-type, high fire point
liquid-insulated, and askarel-insulated transformers installed
indoors and rated over 35 kV shall be in a vault.
(iv) Oil-insulated transformers. If they present a fire hazard
to employees, oil-insulated transformers installed indoors
shall be in a vault.
(v) Fire protection. Combustible material, combustible buildings
and parts of buildings, fire escapes, and door and window
openings shall be safeguarded from fires which may originate
in oil-insulated transformers attached to or adjacent to a
building or combustible material.
(vi) Transformer vaults. Transformer vaults shall be constructed
so as to contain fire and combustible liquids within the vault
and to prevent unauthorized access. Locks and latches shall
be so arranged that a vault door can be readily opened from
the inside.
(vii) Pipes and ducts. Any pipe or duct system foreign to
the vault installation shall not enter or pass through a transformer
vault.
(viii) Material storage. Materials shall not be stored in
transformer vaults.
(f) Capacitors.
(i) Drainage of stored charge. All capacitors, except surge
capacitors or capacitors included as a component part of other
apparatus, shall be provided with an automatic means of draining
the stored charge and maintaining the discharged state after
the capacitor is disconnected from its source of supply.
(ii) Over 600 volts. Capacitors rated over 600 volts, nominal,
shall comply with the following additional requirements:
(A) Isolating or disconnecting switches (with no interrupting
rating) shall be interlocked with the load interrupting
device or shall be provided with prominently displayed caution
signs to prevent switching load current.
(B) For series capacitors the proper switching shall be
assured by use of at least one of the following:
(I) Mechanically sequenced isolating and bypass switches;
(II) Interlocks; or
(III) Switching procedure prominently displayed at the
switching location.
WAC
296-155-452 Specific purpose equipment and installations.
(1) Cranes and hoists. This subsection applies to the installation
of electric equipment and wiring used in connection with cranes,
monorail hoists, hoists, and all runways.
(a) Disconnecting means.
(i) Runway conductor disconnecting means. A readily accessible
disconnecting means shall be provided between the runway contact
conductors and the power supply.
(ii) Disconnecting means for cranes and monorail hoists.
A disconnecting means, capable of being locked in the open
position, shall be provided in the leads from the runway contact
conductors or other power supply on any crane or monorail
hoist.
(A) If this additional disconnecting means is not readily
accessible from the crane or monorail hoist operating station,
means shall be provided at the operating station to open
the power circuit to all motors of the crane or monorail
hoist.
(B) The additional disconnect may be omitted if a monorail
hoist or hand-propelled crane bridge installation meets
all of the following:
(I) The unit is floor controlled;
(II) The unit is within view of the power supply disconnecting
means; and
(III) No fixed work platform has been provided for servicing
the unit.
(b) Control. A limit switch or other device shall be provided
to prevent the load block from passing the safe upper limit
of travel of any hoisting mechanism.
(c) Clearance. The dimension of the working space in the direction
of access to live parts which may require examination, adjustment,
servicing, or maintenance while alive shall be a minimum of
2 feet 6 inches (762 mm). Where controls are enclosed in cabinets,
the door(s) shall open at least 90 degrees or be removable,
or the installation shall provide equivalent access.
(d) Grounding. All exposed metal parts of cranes, monorail
hoists, hoists and accessories including pendant controls shall
be metallically joined together into a continuous electrical
conductor so that the entire crane or hoist will be grounded
in accordance with WAC
296-155-447(6). Moving parts, other than removable accessories
or attachments, having metal-to-metal bearing surfaces shall
be considered to be electrically connected to each other through
the bearing surfaces for grounding purposes. The trolley frame
and bridge frame shall be considered as electrically grounded
through the bridge and trolley wheels and its respective tracks
unless conditions such as paint or other insulating materials
prevent reliable metal-to-metal contact. In this case a separate
bonding conductor shall be provided.
(2) Elevators, escalators, and moving walks.
(a) Disconnecting means. Elevators, escalators, and moving
walks shall have a single means for disconnecting all ungrounded
main power supply conductors for each unit.
(b) Control panels. If control panels are not located in the
same space as the drive machine, they shall be located in cabinets
with doors or panels capable of being locked closed.
(3) Electric welders-disconnecting means.
(a) Motor-generator, AC transformer, and DC rectifier arc welders.
A disconnecting means shall be provided in the supply circuit
for each motor-generator arc welder, and for each AC transformer
and DC rectifier arc welder which is not equipped with a disconnect
mounted as an integral part of the welder.
(b) Resistance welders. A switch or circuit breaker shall 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 shall not be less than the supply conductor
ampacity.
(4) X-ray equipment.
(a) Disconnecting means.
(i) General. A disconnecting means shall be provided in the
supply circuit. The disconnecting means shall be operable
from a location readily accessible from the x-ray control.
For equipment connected to a 120-volt branch circuit of 30
amperes or less, a grounding-type attachment plug cap and
receptacle of proper rating may serve as a disconnecting means.
(ii) More than one piece of equipment. If more than one piece
of equipment is operated from the same high-voltage circuit,
each piece or each group of equipment as a unit shall be provided
with a high-voltage switch or equivalent disconnecting means.
This disconnecting means shall be constructed, enclosed, or
located so as to avoid contact by employees with its live
parts.
(b) Control-radiographic and fluoroscopic types. Radiographic
and fluoroscopic-type equipment shall be effectively enclosed
or shall have interlocks that deenergize the equipment automatically
to prevent ready access to live current-carrying parts.
(1) Scope. This section sets forth requirements for electric
equipment and wiring in locations which are classified depending
on the properties of the flammable vapors, liquids or gases, or
combustible dusts or fibers which may be present therein and the
likelihood that a flammable or combustible concentration or quantity
is present. Each room, section or area shall be considered individually
in determining its classification. These hazardous (classified)
locations are assigned six designations as follows: Class I, Division
1; Class I, Division 2; Class II, Division 1; Class II, Division
2; Class III, Division 1; Class III, Division 2. For definitions
of these locations see WAC
296-155-462. All applicable requirements in this part apply
to all hazardous (classified) locations, unless modified by provisions
of this section.
(a) All components and utilization equipment used in a hazardous
location shall be chosen from among those listed by a nationally
recognized testing laboratory, such as Underwriters' Laboratories,
Inc., or Factory Mutual Engineering Corp., except custom-made
components and utilization equipment.
(b) Equipment approved for a specific hazardous location shall
not be installed or intermixed with equipment approved for another
specific hazardous location.
(2) Electrical installations. Equipment, wiring methods, and
installations of equipment in hazardous (classified) locations
shall be approved as intrinsically safe or approved for the hazardous
(classified) location or safe for the hazardous (classified) location.
Requirements for each of these options are as follows:
(a) Intrinsically safe. Equipment and associated wiring approved
as intrinsically safe is permitted in any hazardous (classified)
location included in its listing or labeling.
(b) Approved for the hazardous (classified) location.
(i) General. Equipment shall be approved not only for the
class of location but also for the ignitible or combustible
properties of the specific gas, vapor, dust, or fiber that
will be present.
Note: NFPA 70, the National Electrical Code,
lists or defines hazardous gases, vapors, and dusts by “groups”
characterized by their ignitible or combustible properties.
(ii) Marking. Equipment shall not be used unless it is marked
to show the class, group, and operating temperature or temperature
range, based on operation in a 40°C ambient, for which it
is approved. The temperature marking shall not exceed the
ignition temperature of the specific gas, vapor, or dust to
be encountered. However, the following provisions modify this
marking requirement for specific equipment:
(A) Equipment of the nonheat-producing type (such as junction
boxes, conduit, and fitting) and equipment of the heat-producing
type having a maximum temperature of not more than 100°C
(212°F) need not have a marked operating temperature or
temperature range.
(B) Fixed lighting fixtures marked for use only in Class
I, Division 2 locations need not be marked to indicate the
group.
(C) Fixed general-purpose equipment in Class I locations,
other than lighting fixtures, which is acceptable for use
in Class I, Division 2 locations need not be marked with
the class, group, division, or operating temperature.
(D) Fixed dust-tight equipment, other than lighting fixtures,
which 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.
(c) Safe for the hazardous (classified) location. Equipment
which is safe for the location shall be of a type and design
which the employer demonstrates will provide protection from
the hazards arising from the combustibility and flammability
of vapors, liquids, gases, dusts, or fibers.
Note: The National Electrical Code, NFPA
70, contains guidelines for determining the type and design of
equipment and installations which will meet this requirement.
The guidelines of this document address electric wiring, equipment,
and systems installed in hazardous (classified) locations and
contain specific provisions for the following: Wiring methods,
wiring connections, conductor insulation, flexible cords, sealing
and drainage, transformers, capacitors, switches, circuit breakers,
fuses, motor controllers, receptacles, attachment plugs, meters,
relays, instruments, resistors, generators, motors, lighting fixtures,
storage battery charging equipment, electric cranes, electric
hoists and similar equipment, utilization equipment, signaling
systems, alarm systems, remote control systems, local loud speaker
and communication systems, ventilation piping, live parts, lightning
surge protection, and grounding. Compliance with these guidelines
will constitute one means, but not the only means, of compliance
with this subsection.
(3) Conduits. All conduits shall be threaded and shall be made
wrench-tight. Where it is impractical to make a threaded joint
tight, a bonding jumper shall be utilized.
(1) Systems over 600 volts, nominal. (a) through (d) of this
subsection contain general requirements for all circuits and equipment
operated at over 600 volts.
(a) Wiring methods for fixed installations.
(i) Above ground. Above-ground conductors shall 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 designed for the use and purpose.
However, open runs of nonmetallic-sheathed cable or of bare
conductors or busbars may be installed in locations which
are accessible only to qualified persons. Metallic shielding
components, such as tapes, wires, or braids for conductors,
shall be grounded. Open runs of insulated wires and cables
having a bare lead sheath or a braided outer covering shall
be supported in a manner designed to prevent physical damage
to the braid or sheath.
(ii) Installations emerging from the ground. Conductors emerging
from the ground shall be enclosed in raceways. Raceways installed
on poles shall be of rigid metal conduit, intermediate metal
conduit, PVC schedule 80 or equivalent extending from the
ground line up to a point 8 feet (2.44 m) above finished grade.
Conductors entering a building shall be protected by an enclosure
from the ground line to the point of entrance. Metallic enclosures
shall be grounded.
(b) Interrupting and isolating devices.
(i) Circuit breakers. Circuit breakers located indoors shall
consist of metal-enclosed or fire-resistant, cell-mounted
units. In locations accessible only to qualified personnel,
open mounting of circuit breakers is permitted. A means of
indicating the open and closed position of circuit breakers
shall be provided.
(ii) Fused cutouts. Fused cutouts installed in buildings
or transformer vaults shall be of a type identified for the
purpose. They shall be readily accessible for fuse replacement.
(iii) Equipment isolating means. A means shall be provided
to completely isolate equipment for inspection and repairs.
Isolating means which are not designed to interrupt the load
current of the circuit shall be either interlocked with a
circuit interrupter or provided with a sign warning against
opening them under load.
(c) Mobile and portable equipment.
(i) Power cable connections to mobile machines. A metallic
enclosure shall be provided on the mobile machine for enclosing
the terminals of the power cable. The enclosure shall include
provisions for a solid connection for the ground wire(s) terminal
to ground effectively the machine frame. The method of cable
termination used shall prevent any strain or pull on the cable
from stressing the electrical connections. The enclosure shall
have provision for locking so only authorized qualified persons
may open it and shall be marked with a sign warning of the
presence of energized parts.
(ii) Guarding live parts. All energized switching and control
parts shall be enclosed in effectively grounded metal cabinets
or enclosures. Circuit breakers and protective equipment shall
have the operating means projecting through the metal cabinet
or enclosure so these units can be reset without locked doors
being opened. Enclosures and metal cabinets shall be locked
so that only authorized qualified persons have access and shall
be marked with a sign warning of the presence of energized parts.
Collector ring assemblies on revolving-type machines (shovels,
draglines, etc.) shall be guarded.
(d) Tunnel installations.
(i) Application. The provisions of this item apply to installation
and use of high-voltage power distribution and utilization
equipment which is associated with tunnels and which is portable
and/or mobile, such as substations, trailers, cars, mobile
shovels, draglines, hoists, drills, dredges, compressors,
pumps, conveyors, and underground excavators.
(ii) Conductors. Conductors in tunnels shall be installed
in one or more of the following:
(A) Metal conduit or other metal raceway;
(B) Type MC cable; or
(C) Other suitable multiconductor cable.
Conductors shall also be so located or guarded as to protect
them from physical damage. Multiconductor portable cable may
supply mobile equipment. An equipment grounding conductor shall
be run with circuit conductors inside the metal raceway or inside
the multiconductor cable jacket. The equipment grounding conductor
may be insulated or bare.
(iii) Guarding live parts. Bare terminals of transformers,
switches, motor controllers, and other equipment shall be
enclosed to prevent accidental contact with energized parts.
Enclosures for use in tunnels shall be drip-proof, weatherproof,
or submersible as required by the environmental conditions.
(iv) Disconnecting means. A disconnecting means that simultaneously
opens all ungrounded conductors shall be installed at each
transformer or motor location.
(v) Grounding and bonding. All nonenergized metal parts of
electric equipment and metal raceways and cable sheaths shall
be grounded and bonded to all metal pipes and rails at the
portal and at intervals not exceeding 1000 feet (305 m) throughout
the tunnel.
(2) Class 1, Class 2, and Class 3 remote control, signaling,
and power-limited circuits.
(a) Classification. 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
in accordance with their respective voltage and power limitations
as summarized in (a)(i) through (iii) of this subsection.
(i) Class 1 circuits.
(A) A Class 1 power-limited circuit is supplied from a
source having a rated output of not more than 30 volts and
1000 volt-amperes.
(B) A Class 1 remote control circuit or a Class 1 signaling
circuit has a voltage which does not exceed 600 volts; however,
the power output of the source need not be limited.
(ii) Class 2 and Class 3 circuits.
(A) 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.
(B) 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.
(C) 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.
(iii) Application. The maximum circuit voltages in (a)(i)
and (ii) of this subsection apply to sinusoidal AC or continuous
DC power sources, and where wet contact occurrence is not
likely.
(b) Marking. A Class 2 or Class 3 power supply unit shall not
be used unless it is durably marked where plainly visible to
indicate the class of supply and its electrical rating.
(3) Communications systems.
(a) Scope. These provisions for communication systems apply
to such systems as central-station-connected and noncentral-station-connected
telephone circuits, radio receiving and transmitting equipment,
and outside wiring for fire and burglar alarm, and similar central
station systems. These installations need not comply with the
provisions of WAC 296-155-444
through 296-155-459(2),
except WAC
296-155-447 (3)(a)(ii) and 296-155-456.
(b) Protective devices.
(i) Circuits exposed to power conductors. Communication circuits
so located as to be exposed to accidental contact with light
or power conductors operating at over 300 volts shall have
each circuit so exposed provided with an approved protector.
(ii) Antenna lead-ins. Each conductor of a lead-in from an
outdoor antenna shall be provided with an antenna discharge
unit or other means that will drain static charges from the
antenna system.
(c) Conductor location.
(i) Outside of buildings.
(A) Receiving distribution lead-in or aerial-drop cables
attached to buildings and lead-in conductors to radio transmitters
shall be so installed as to avoid the possibility of accidental
contact with electric light or power conductors.
(B) The clearance between lead-in conductors and any lightning
protection conductors shall not be less than 6 feet (1.83
m).
(ii) On poles. Where practicable, communication conductors
on poles shall be located below the light or power conductors.
Communications conductors shall not be attached to a crossarm
that carries light or power conductors.
(iii) Inside of buildings. Indoor antennas, lead-ins, and
other communication conductors attached as open conductors
to the inside of buildings shall be located at least 2 inches
(50.8 mm) from conductors of any light or power or Class 1
circuits unless a special and equally protective method of
conductor separation is employed.
(d) Equipment location. Outdoor metal structures supporting
antennas, as well as self-supporting antennas such as vertical
rods or dipole structures, shall be located as far away from
overhead conductors of electric light and power circuits of
over 150 volts to ground as necessary to avoid the possibility
of the antenna or structure falling into or making accidental
contact with such circuits.
(e) Grounding.
(i) Lead-in conductors. If exposed to contact with electric
light or power conductors, the metal sheath of aerial cables
entering buildings shall be grounded or shall be interrupted
close to the entrance to the building by an insulating joint
or equivalent device. Where protective devices are used, they
shall be grounded.
(ii) Antenna structures. Masts and metal structures supporting
antennas shall be permanently and effectively grounded without
splice or connection in the grounding conductor.
(iii) Equipment enclosures. Transmitters shall be enclosed
in a metal frame or grill or separated from the operating
space by a barrier, all metallic parts of which are effectively
connected to ground. All external metal handles and controls
accessible to the operating personnel shall be effectively
grounded. Unpowered equipment and enclosures shall be considered
grounded where connected to an attached coaxial cable with
an effectively grounded metallic shield.
The definitions given in this section apply to the terms used
in Part I. The definitions given here for “approved”
and “qualified person” apply, instead of the definitions
given in WAC
296-155-012, to the use of these terms in Part I.
(1) “Acceptable.” An installation or equipment
is acceptable to the director, and approved within the meaning
of this Part I:
(a) If it is accepted, certified, listed, labeled, or otherwise
determined to be safe by a qualified testing laboratory capable
of determining the suitability of materials and equipment for
installation and use in accordance with this standard; or
(b) With respect to an installation or equipment of a kind
which no qualified testing laboratory accepts, certifies, lists,
labels, or determines to be safe, if it is inspected or tested
by another state agency, or by a federal, municipal, or other
local authority responsible for enforcing occupational safety
provisions of the National Electrical Code, and found in compliance
with those provisions; or
(c) With respect to custom-made equipment or related installations
which are designed, fabricated for, and intended for use by
a particular customer, if it is determined to be safe for its
intended use by its manufacturer on the basis of test data which
the employer keeps and makes available for inspection to the
director and his/her authorized representatives.
(2) “Accepted.” An installation is “accepted”
if it has been inspected and found to be safe by a qualified
testing laboratory.
(3) “Accessible.” (As applied to wiring methods.)
Capable of being removed or exposed without damaging the building
structure or finish, or not permanently closed in by the structure
or finish of the building. (See “concealed” and “exposed.”)
(4) “Accessible.” (As applied to equipment.)
Admitting close approach; not guarded by locked doors, elevation,
or other effective means. (See “readily accessible.”)
(5) “Ampacity.” The current in amperes a
conductor can carry continuously under the conditions of use without
exceeding its temperature rating.
(6) “Appliances.” Utilization equipment,
generally other than industrial, normally built in standardized
sizes or types, which is installed or connected as a unit to perform
one or more functions.
(7) “Approved.” Approved by the director
of the department of Labor & Industries or his/her authorized
representative: Provided, however, That should a provision of
this chapter state that approval by an agency or organization
other than the department of Labor & Industries is required,
such as Underwriters' Laboratories, the Bureau of Mines, or Mine
Safety and Health Administration (MSHA) and the National Institute
for Occupational Safety and Health (NIOSH) the provisions of WAC
296-155-006 shall apply.
(8) “Askarel.” A generic term for a group
of nonflammable synthetic chlorinated hydrocarbons used as electrical
insulating media. Askarels of various compositional types are
used. Under arcing conditions the gases produced, while consisting
predominantly of noncombustible hydrogen chloride, can include
varying amounts of combustible gases depending upon the askarel
type.
(9) “Attachment plug (plug cap) (cap).”
A device which, by insertion in a receptacle, establishes connection
between the conductors of the attached flexible cord and the conductors
connected permanently to the receptacle.
(10) “Automatic.” Self-acting, operating
by its own mechanism when actuated by some impersonal influence,
as for example, a change in current strength, pressure, temperature,
or mechanical configuration.
(11) “Bare conductor.” See “conductor.”
(12) “Bonding.” The permanent joining of
metallic parts to form an electrically conductive path which will
assure electrical continuity and the capacity to conduct safely
any current likely to be imposed.
(13) “Bonding jumper.” A reliable conductor
to assure the required electrical conductivity between metal parts
required to be electrically connected.
(14) “Branch circuits.” That portion of
a wiring system extending beyond the final overcurrent device
protecting the circuit. (A device not approved for branch circuit
protection, such as thermal cutout or motor overload protective
device, is not considered as the overcurrent device protecting
the circuit.)
(15) “Building.” A structure which stands
alone or which is cut off from adjoining structures by fire walls
with all openings therein protected by approved fire doors.
(16) “Cabinet.” An enclosure designed either
for surface or flush mounting, and provided with a frame, mat,
or trim in which a swinging door or doors are or may be hung.
(17) “Certified.” Equipment is “certified”
if it:
(a) Has been tested and found by a qualified testing laboratory
to meet applicable test standards or to be safe for use in a
specified manner; and
(b) Is of a kind whose production is periodically inspected
by a qualified testing laboratory. Certified equipment must
bear a label, tag, or other record of certification.
(18) “Circuit breaker.”
(a) (600 volts nominal, or less.) A device designed to open
and close a circuit by nonautomatic means and to open the circuit
automatically on a predetermined overcurrent without injury
to itself when properly applied within its rating.
(b) (Over 600 volts, nominal.) A switching device capable of
making, carrying, and breaking currents under normal circuit
conditions, and also making, carrying for a specified time,
and breaking currents under specified abnormal circuit conditions,
such as those of short circuit.
(19) “Class I locations.” 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 ignitible
mixtures. Class I locations include the following:
(a) Class I, Division 1. A Class I, Division 1 location is
a location:
(i) In which ignitible concentrations of flammable gases
or vapors may exist under normal operating conditions; or
(ii) In which ignitible concentrations of such gases or vapors
may exist frequently because of repair or maintenance operations
or because of leakage; or
(iii) In which breakdown or faulty operation of equipment
or processes might release ignitible concentrations of flammable
gases or vapors, and might also cause simultaneous failure
of electric equipment.
Note: 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;
inadequately ventilated pump rooms for flammable gas or for volatile
flammable liquids; and all other locations where ignitible concentrations
of flammable vapors or gases are likely to occur in the course
of normal operations.
(b) Class I, Division 2. A Class I, Division 2 location is
a location:
(i) In which volatile flammable liquids or flammable gases
are handled, processed, or used, but in which the hazardous
liquids, vapors, or gases will normally be confined within
closed containers or closed systems from which they can escape
only in case of accidental rupture or breakdown of such containers
or systems, or in case of abnormal operation of equipment;
or
(ii) In which ignitible concentrations of gases or vapors
are normally prevented by positive mechanical ventilation,
and which might become hazardous through failure or abnormal
operations of the ventilating equipment; or
(iii) That is adjacent to a Class I, Division 1 location,
and to which ignitible concentrations of gases or vapors might
occasionally be communicated unless such communication is
prevented by adequate positive-pressure ventilation from a
source of clean air, and effective safeguards against ventilation
failure are provided.
Note: 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 of some 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 that merit consideration in determining
the classification and extent of each location.
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 of liquefied or compressed
gases in sealed containers would not normally be considered
hazardous unless also subject to other hazardous conditions.
Electrical conduits and their associated enclosures separated
from process fluids by a single seal or barrier are classed
as a Division 2 location if the outside of the conduit and
enclosures is a nonhazardous location.
(20) “Class II locations.” Class II locations
are those that are hazardous because of the presence of combustible
dust. Class II locations include the following:
(a) Class II, Division 1. A Class II, Division 1 location is
a location:
(i) In which combustible dust is or may be in suspension
in the air under normal operating conditions, in quantities
sufficient to produce explosive or ignitible mixtures; or
(ii) Where mechanical failure or abnormal operation of machinery
or equipment might cause such explosive or ignitible mixtures
to be produced, and might also provide a source of ignition
through simultaneous failure of electric equipment, operation
of protection devices, or from other causes; or
(iii) In which combustible dusts of an electrically conductive
nature may be present.
Note: Combustible dusts which 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 woodflour, oil meal from beans and seed, dried hay, and other
organic materials which 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. A Class II, Division 2 location is
a location in which:
(i) Combustible dust will not normally be in suspension in
the air in quantities sufficient to produce explosive or ignitible
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 dust accumulations resulting therefrom may be ignitible
by abnormal operation or failure of electrical equipment or
other apparatus.
Note: 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, as described above, into which an explosive or ignitible
concentration of dust may be put into suspension under abnormal
operating conditions.
(21) “Class III locations.” Class III locations
are those that are hazardous because of the presence of easily
ignitible fibers or flyings but in which such fibers or flyings
are not likely to be in suspension in the air in quantities sufficient
to produce ignitible mixtures. Class III locations include the
following:
(a) Class III, Division 1. A Class III, Division 1 location
is a location in which easily ignitible fibers or materials
producing combustible flyings are handled, manufactured, or
used.
Note: Easily ignitible 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, sawdust, woodchips,
and other material of similar nature.
(b) Class III, Division 2. A Class III, Division 2 location
is a location in which easily ignitible fibers are stored or
handled, except in process of manufacture. Collector ring. A
collector ring is an assembly of slip rings for transferring
electrical energy from a stationary to a rotating member.
(22) “Collector ring.” A collector ring
is an assembly of slip rings for transferring electrical energy
from a stationary to a rotating member.
(23) “Concealed.” Rendered inaccessible
by the structure or finish of the building. Wires in concealed
raceways are considered concealed, even though they may become
accessible by withdrawing them. See “accessible. (As applied
to wiring methods.)”
(24) “Conductor.”
(a) Bare. A conductor having no covering or electrical insulation
whatsoever.
(b) Covered. A conductor encased within material of composition
or thickness that is not recognized as electrical insulation.
(c) Insulated. A conductor encased within material of composition
and thickness that is recognized as electrical insulation.
(25) “Controller.” A device or group of devices
that serves to govern, in some predetermined manner, the electric
power delivered to the apparatus to which it is connected.
(26) “Covered conductor.” See “conductor.”
(27) “Cutout.” (Over 600 volts, nominal.)
An assembly of a fuse support with either a fuseholder, fuse carrier,
or disconnecting blade. The fuseholder or fuse carrier may include
a conducting element (fuse link), or may act as the disconnecting
blade by the inclusion of a nonfusible member.
(28) “Cutout box.” An enclosure designed
for surface mounting and having swinging doors or covers secured
directly to and telescoping with the walls of the box proper.
(See “cabinet.”)
(29) “Damp location.” See “location.”
(30) “Dead front.” Without live parts exposed
to a person on the operating side of the equipment.
(31) “Device.” A unit of an electrical system
which is intended to carry but not utilize electric energy.
(32) “Disconnecting means.” A device, or
group of devices, or other means by which the conductors of a
circuit can be disconnected from their source of supply.
(33) “Disconnecting (or isolating) switch.”
(Over 600 volts, nominal.) A mechanical switching device used
for isolating a circuit or equipment from a source of power.
(34) “Dry location.” See “location.”
(35) “Enclosed.” Surrounded by a case, housing,
fence or walls which will prevent persons from accidentally contacting
energized parts.
(36) “Enclosure.” The case or housing of
apparatus, or the fence or walls surrounding an installation to
prevent personnel from accidentally contacting energized parts,
or to protect the equipment from physical damage.
(37) “Equipment.” A general term including
material, fittings, devices, appliances, fixtures, apparatus,
and the like, used as a part of, or in connection with, an electrical
installation.
(38) “Equipment grounding conductor.” See
“grounding conductor, equipment.”
(39) “Explosion-proof apparatus.” Apparatus
enclosed in a case that is capable of withstanding an explosion
of a specified gas or vapor which may occur within it and of preventing
the ignition of a specified gas or vapor surrounding the enclosure
by sparks, flashes, or explosion of the gas or vapor within, and
which operates at such an external temperature that it will not
ignite a surrounding flammable atmosphere.
(40) “Exposed. (As applied to live parts.)”
Capable of being inadvertently touched or approached nearer than
a safe distance by a person. It is applied to parts not suitably
guarded, isolated, or insulated. (See “accessible”
and “concealed.”)
(41) “Exposed. (As applied to wiring methods.)”
On or attached to the surface or behind panels designed to allow
access. See “accessible. (As applied to wiring methods.)”
(42) “Exposed. (For the purposes of WAC
296-155-459(3), Communications systems.)” Where
the circuit is in such a position that in case of failure of supports
or insulation, contact with another circuit may result.
(43) “Externally operable.” Capable of being
operated without exposing the operator to contact with live parts.
(44) “Feeder.” All circuit conductors between
the service equipment, or the generator switchboard of an isolated
plant, and the final branch-circuit overcurrent device.
(45) “Festoon lighting.” A string of outdoor
lights suspended between two points more than 15 feet (4.57 m)
apart.
(46) “Fitting.” An accessory such as a locknut,
bushing, or other part of a wiring system that is intended primarily
to perform a mechanical rather than an electrical function.
(47) “Fuse.” (Over 600 volts, nominal.) An
overcurrent protective device with a circuit opening fusible part
that is heated and severed by the passage of overcurrent through
it. A fuse comprises all the parts that form a unit capable of
performing the prescribed functions. It may or may not be the
complete device necessary to connect it into an electrical circuit.
(48) “Ground.” A conducting connection, whether
intentional or accidental, between an electrical circuit or equipment
and the earth, or to some conducting body that serves in place
of the earth.
(49) “Grounded.” Connected to earth or to
some conducting body that serves in place of the earth.
(50) “Grounded, effectively.” (Over 600 volts,
nominal.) Permanently connected to earth through a ground connection
of sufficiently low impedance and having sufficient ampacity that
ground fault current which may occur cannot build up to voltages
dangerous to personnel.
(51) “Grounded conductor.” A system or circuit
conductor that is intentionally grounded.
(52) “Grounding conductor.” A conductor used
to connect equipment or the grounded circuit of a wiring system
to a grounding electrode or electrodes.
(53) “Grounding conductor, equipment.” The
conductor used to connect the noncurrent-carrying metal parts
of equipment, raceways, and other enclosures to the system grounded
conductor and/or the grounding electrode conductor at the service
equipment or at the source of a separately derived system.
(54) “Grounding electrode conductor.” The
conductor used to connect the grounding electrode to the equipment
grounding conductor and/or to the grounded conductor of the circuit
at the service equipment or at the source of a separately derived
system.
(55) “Ground-fault circuit interrupter.”
A device for the protection of personnel that functions to deenergize
a circuit or portion thereof within an established period of time
when a current to ground exceeds some predetermined value that
is less than that required to operate the overcurrent protective
device of the supply circuit.
(56) “Guarded.” Covered, shielded, fenced,
enclosed, or otherwise protected by means of suitable covers,
casings, barriers, rails, screens, mats, or platforms to remove
the likelihood of approach to a point of danger or contact by
persons or objects.
(57) “Hazard.” That condition, potential
or inherent, which is likely to cause injury, death, or occupational
disease.
(58) “Hoistway.” Any shaftway, hatchway,
well hole, or other vertical opening or space in which an elevator
or dumbwaiter is designed to operate.
(59) “Identified (conductors or terminals).”
Identified, as used in reference to a conductor or its terminal,
means that such conductor or terminal can be recognized as grounded.
(60) “Identified (for the use).” Recognized
as suitable for the specific purpose, function, use, environment,
application, etc., where described as a requirement in this standard.
Suitability of equipment for a specific purpose, environment,
or application is determined by a qualified testing laboratory
where such identification includes labeling or listing.
(61) “Insulated conductor.” See conductor.”
(62) “Interrupter switch.” (Over 600 volts, nominal.)
A switch capable of making, carrying, and interrupting specified
currents.
(63) “Intrinsically safe equipment and associated wiring.”
Equipment and associated wiring in which any spark or thermal
effect, produced either normally or in specified fault conditions,
is incapable, under certain prescribed test conditions, of causing
ignition of a mixture of flammable or combustible material in
air in its most easily ignitible concentration.
(64) “Isolated.” Not readily accessible to
persons unless special means for access are used.
(65) “Isolated power system.” A system comprising
an isolating transformer or its equivalent, a line isolation monitor,
and its ungrounded circuit conductors.
(66) “J-Box (junction box).” An electrical
sheet metal enclosure with openings for conduit or cable with
sheet metal cover. The primary purpose is for joining conductors
for splicing.
(67) “Labeled.” Equipment or materials to
which has been attached a label, symbol or other identifying mark
of a qualified testing laboratory which indicates compliance with
appropriate standards or performance in a specified manner.
(68) “Lighting outlet.” An outlet intended
for the direct connection of a lampholder, a lighting fixture,
or a pendant cord terminating in a lampholder.
(69) “Listed.” Equipment or materials included
in a list published by a qualified testing laboratory whose listing
states either that the equipment or material meets appropriate
standards or has been tested and found suitable for use in a specified
manner.
(70) “Location.”
(a) Damp location. Partially protected locations under canopies,
marquees, roofed open porches, and like locations, and interior
locations subject to moderate degrees of moisture, such as some
basements.
(b) Dry location. A location not normally subject to dampness
or wetness. A location classified as dry may be temporarily
subject to dampness or wetness, as in the case of a building
under construction.
(c) Wet location. Installations underground or in concrete
slabs or masonry in direct contact with the earth, and locations
subject to saturation with water or other liquids, such as locations
exposed to weather and unprotected.
(71) “Mobile x-ray.” X-ray equipment mounted
on a permanent base with wheels and/or casters for moving while
completely assembled.
(72) “Motor control center.” An assembly
of one or more enclosed sections having a common power bus and
principally containing motor control units.
(73) “Outlet.” A point on the wiring system
at which current is taken to supply utilization equipment.
(74) “Overcurrent.” Any current in excess
of the rated current of equipment or the ampacity of a conductor.
It may result from overload (see definition), short circuit, or
ground fault. A current in excess of rating may be accommodated
by certain equipment and conductors for a given set of conditions.
Hence the rules for overcurrent protection are specific for particular
situations.
(75) “Overload.” Operation of equipment
in excess of normal, full load rating, or of a conductor in excess
of rated ampacity which, when it persists for a sufficient length
of time, would cause damage or dangerous overheating. A fault,
such as a short circuit or ground fault, is not an overload. (See
“overcurrent.”)
(76) “Panelboard.” A single panel or group
of panel units designed for assembly in the form of a single panel;
including buses, automatic overcurrent devices, and with or without
switches for the control of light, heat, or power circuits; designed
to be placed in a cabinet or cutout box placed in or against a
wall or partition and accessible only from the front. (See “switchboard.”)
(77) “Portable x-ray.” X-ray equipment designed
to be hand-carried.
(78) “Power fuse.” (Over 600 volts, nominal.)
See “fuse.”
(79) “Power outlet.” An enclosed assembly
which may include receptacles, circuit breakers, fuseholders,
fused switches, buses and watt-hour meter mounting means; intended
to serve as a means for distributing power required to operate
mobile or temporarily installed equipment.
(80) “Premises wiring system.” That interior
and exterior wiring, including power, lighting, control, and signal
circuit wiring together with all of its associated hardware, fittings,
and wiring devices, both permanently and temporarily installed,
which extends from the load end of the service drop, or load end
of the service lateral conductors to the outlet(s). Such wiring
does not include wiring internal to appliances, fixtures, motors,
controllers, motor control centers, and similar equipment.
(81) “Qualified person.” One familiar with
the construction and operation of the equipment and the hazards
involved.
(82) “Qualified testing laboratory.” A properly
equipped and staffed testing laboratory which has capabilities
for and which provides the following services:
(a) Experimental testing for safety of specified items of equipment
and materials referred to in this standard to determine compliance
with appropriate test standards or performance in a specified
manner;
(b) Inspecting the run of such items of equipment and materials
at factories for product evaluation to assure compliance with
the test standards;
(c) Service-value determinations through field inspections
to monitor the proper use of labels on products and with authority
for recall of the label in the event a hazardous product is
installed;
(d) Employing a controlled procedure for identifying the listed
and/or labeled equipment or materials tested; and
(e) Rendering creditable reports or findings that are objective
and without bias of the tests and test methods employed.
(83) “Raceway.” A channel designed expressly
for holding wires, cables, or busbars, with additional functions
as permitted in this part. Raceways may be of metal or insulating
material, and the term includes rigid metal conduit, rigid nonmetallic
conduit, intermediate metal conduit, liquidtight flexible metal
conduit, flexible metallic tubing, flexible metal conduit, electrical
metallic tubing, underfloor raceways, cellular concrete floor
raceways, cellular metal floor raceways, surface raceways, wireways,
and busways.
(84) “Readily accessible.” Capable of being
reached quickly for operation, renewal, or inspections, without
requiring those to whom ready access is requisite to climb over
or remove obstacles or to resort to portable ladders, chairs,
etc. (See “accessible.”)
(85) “Receptacle.” A receptacle is a contact
device installed at the outlet for the connection of a single
attachment plug. A single receptacle is a single contact device
with no other contact device on the same yoke. A multiple receptacle
is a single device containing two or more receptacles.
(86) “Receptacle outlet.” An outlet where
one or more receptacles are installed.
(87) “Remote-control circuit.” Any electric
circuit that controls any other circuit through a relay or an
equivalent device.
(88) “Sealable equipment.” Equipment enclosed
in a case or cabinet that is provided with a means of sealing
or locking so that live parts cannot be made accessible without
opening the enclosure. The equipment may or may not be operable
without opening the enclosure.
(89) “Separately derived system.” A premises
wiring system whose power is derived from generator, transformer,
or converter windings and has no direct electrical connection,
including a solidly connected grounded circuit conductor, to supply
conductors originating in another system.
(90) “Service.” The conductors and equipment
for delivering energy from the electricity supply system to the
wiring system of the premises served.
(91) “Service conductors.” The supply conductors
that extend from the street main or from transformers to the service
equipment of the premises supplied.
(92) “Service drop.” The overhead service
conductors from the last pole or other aerial support to and including
the splices, if any, connecting to the service-entrance conductors
at the building or other structure.
(93) “Service-entrance conductors, overhead system.”
The service conductors between the terminals of the service
equipment and a point usually outside the building, clear of building
walls, where joined by tap or splice to the service drop.
(94) “Service-entrance conductors, underground system.”
The service conductors between the terminals of the service equipment
and the point of connection to the service lateral. Where service
equipment is located outside the building walls, there may be
no service-entrance conductors, or they may be entirely outside
the building.
(95) “Service equipment.” The necessary
equipment, usually consisting of a circuit breaker or switch and
fuses, and their accessories, located near the point of entrance
of supply conductors to a building or other structure, or an otherwise
defined area, and intended to constitute the main control and
means of cutoff of the supply.
(96) “Service raceway.” The raceway that
encloses the service-entrance conductors.
(97) “Shock hazard.” To exist 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.
(98) “Signaling circuit.” Any electric circuit
that energizes signaling equipment.
(99) “Switchboard.” A large single panel,
frame, or assembly of panels which have switches, buses, instruments,
overcurrent and other protective devices mounted on the face or
back or both. Switchboards are generally accessible from the rear
as well as from the front and are not intended to be installed
in cabinets. (See “panelboard.”)
(100) “Switches.”
(a) General-use switch. A switch intended for use in general
distribution and branch circuits. It is rated in amperes, and
it is capable of interrupting its rated current at its rated
voltage.
(b) General-use snap switch. A form of general-use switch so
constructed that it can be installed in flush device boxes or
on outlet box covers, or otherwise used in conjunction with
wiring systems recognized by this part.
(c) Isolating switch. A switch intended for isolating an electric
circuit from the source of power. It has no interrupting rating,
and it is intended to be operated only after the circuit has
been opened by some other means.
(d) Motor-circuit switch. A switch, rated in horsepower, capable
of interrupting the maximum operating overload current of a
motor of the same horsepower rating as the switch at the rated
voltage.
(101) “Switching devices.” (Over 600 volts,
nominal.) Devices designed to close and/or open one or more electric
circuits. Included in this category are circuit breakers, cutouts,
disconnecting (or isolating) switches, disconnecting means, and
interrupter switches.
(102) “Transformer.” A transformer is an apparatus
for converting electrical power in an a-c system at one voltage
or current into electrical power at some other voltage or current
without the use of rotating parts.
(103) “Transportable x-ray.” X-ray equipment
installed in a vehicle or that may readily be disassembled for
transport in a vehicle.
(104) “Utilization equipment.” Utilization
equipment means equipment which utilizes electric energy for mechanical,
chemical, heating, lighting, or similar useful purpose.
(105) “Utilization system.” A utilization
system is a system which provides electric power and light for
employee workplaces, and includes the premises wiring system and
utilization equipment.
(106) “Ventilated.” Provided with a means
to permit circulation of air sufficient to remove an excess of
heat, fumes, or vapors.
(107) “Volatile flammable liquid.” A flammable
liquid having a flash point below 38°C (100°F) or whose temperature
is above its flash point, or a Class II combustible liquid having
a vapor pressure not exceeding 40 psia (276 kPa) at 38°C (100°F)
whose temperature is above its flash point.
(108) “Voltage.” (Of a circuit.) The greatest
root-mean-square (effective) difference of potential between any
two conductors of the circuit concerned.
(109) “Voltage, nominal.” A nominal value
assigned to a circuit or system for the purpose of conveniently
designating its voltage class (as 120/240, 480Y/277, 600, etc.).
The actual voltage at which a circuit operates can vary from the
nominal within a range that permits satisfactory operation of
equipment.
(110) “Voltage to ground.” For grounded circuits,
the voltage between the given conductor and that point or conductor
of the circuit that is grounded; for ungrounded circuits, the
greatest voltage between the given conductor and any other conductor
of the circuit.
(111) “Watertight.” So constructed that moisture
will not enter the enclosure.
(112) “Weatherproof.” So constructed or protected
that exposure to the weather will not interfere with successful
operation. Rainproof, raintight, or watertight equipment can fulfill
the requirements for weatherproof where varying weather conditions
other than wetness, such as snow, ice, dust, or temperature extremes,
are not a factor.
For
printing