(1)
Wiring
methods. The provisions of this section do not apply to conductors that
are an integral part of factory-assembled equipment.
(a)
General requirements.
(i) You must effectively bond metal raceways,
cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other
metal noncurrent-carrying parts that are to serve as grounding conductors, with
or without the use of supplementary equipment grounding conductors, where
necessary to ensure electrical continuity and the capacity to conduct safely
any fault current likely to be imposed on them. You must remove any
nonconductive paint, enamel, or similar coating at threads, contact points, and
contact surfaces or be connected by means of fittings designed so as to make
such removal unnecessary.
(ii)
Where necessary for the reduction of electrical noise (electromagnetic
interference) of the grounding circuit, an equipment enclosure supplied by a
branch circuit may be isolated from a raceway containing circuits supplying
only that equipment by one or more listed nonmetallic raceway fittings located
at the point of attachment of the raceway to the equipment enclosure. You must
supplement the metal raceway by an internal insulated equipment grounding
conductor installed to ground the equipment enclosure.
(iii) No wiring systems of any type may be
installed in ducts used to transport dust, loose stock, or flammable vapors. No
wiring system of any type may be installed in any duct used for vapor removal
or for ventilation of commercial-type cooking equipment, or in any shaft
containing only such ducts.
(b)
Temporary wiring. Except as
specifically modified in this subsection, all other requirements of this part
for permanent wiring must also apply to temporary wiring installations.
(i) Temporary electrical power and lighting
installations of 600 volts, nominal, or less may be used only as follows:
(A) During and for remodeling, maintenance,
repair or demolition of buildings, structures, or equipment, and similar
activities;
(B) For a period not to
exceed ninety days for Christmas decorative lighting, carnivals, and similar
purposes; or
(C) For experimental
or development work, and during emergencies.
(ii) You must remove temporary wiring
immediately upon completion of the project or purpose for which the wiring was
installed.
(iii) Temporary
electrical installations of more than 600 volts may be used only during periods
of tests, experiments, emergencies, or construction-like activities.
(iv) The following requirements apply to
feeders:
(A) Feeders must originate in an
approved distribution center.
(B)
Conductors must be run as multiconductor cord or cable assemblies. However, if
installed as permitted in (b)(i)(C) of this subsection, and if accessible only
to qualified persons, feeders may be run as single insulated
conductors.
(v) The
following requirements apply to branch circuits:
(A) Branch circuits must originate in an
approved power outlet or panelboard.
(B) 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.
(C) No branch-circuit conductor may be laid
on the floor.
(D) Each branch
circuit that supplies receptacles or fixed equipment must contain a separate
equipment grounding conductor if run as open conductors.
(vi) Receptacles must be of the grounding
type. Unless installed in a continuous grounded metallic raceway or metallic
covered cable, each branch circuit must contain a separate equipment grounding
conductor and all receptacles must be electrically connected to the grounding
conductor.
(vii) No bare conductors
nor earth returns may be used for the wiring of any temporary
circuit.
(viii) You must install
suitable disconnecting switches or plug connectors to permit the disconnection
of all ungrounded conductors of each temporary circuit. You must provide
multiwire branch circuits with a means to disconnect simultaneously all
ungrounded conductors at the power outlet or panelboard where the branch
circuit originated.
Note: Circuit breakers with their handles
connected by approved handle ties are considered a single disconnecting means
for the purpose of this requirement.
(ix) You must protect all lamps for general
illumination from accidental contact or breakage by a suitable fixture or
lampholder with a guard. Brass shell, paper-lined sockets, or other metal-cased
sockets may not be used unless the shell is grounded.
(x) You must protect flexible cords and
cables from accidental damage, as might be caused, for example, by sharp
corners, projections, and doorways or other pinch points.
(xi) You must support cable assemblies and
flexible cords and cables in place at intervals that ensure that they will be
protected from physical damage. Support must be in the form of staples, cables
ties, straps, or similar type fittings installed so as not to cause
damage.
(c)
Cable
trays.
(i) Only the following wiring
methods may be installed in cable tray systems: Armored cable; electrical
metallic tubing; electrical nonmetallic tubing; fire alarm cables; flexible
metal conduit; flexible metallic tubing; instrumentation tray cable;
intermediate metal conduit; liquid tight flexible metal conduit; liquid tight
flexible nonmetallic conduit; metal-clad cable; mineral-insulated,
metal-sheathed cable; multiconductor service-entrance cable; multiconductor
underground feeder and branch-circuit cable; multipurpose and communications
cables; nonmetallic-sheathed cable; power and control tray cable; power-limited
tray cable; optical fiber cables; and other factory-assembled, multiconductor
control, signal, or power cables that are specifically approved for
installation in cable trays, rigid metal conduit, and rigid nonmetallic
conduit.
(ii) In industrial
establishments where conditions of maintenance and supervision assure that only
qualified persons will service the installed cable tray system, the following
cables may also be installed in ladder, ventilated-trough, or
ventilated-channel cable trays:
(A) Single
conductor cable; the cable must be No. 1/0 or larger and must be of a type
listed and marked on the surface for use in cable trays; where Nos. 1/0 through
4/0 single conductor cables are installed in ladder cable tray, the maximum
allowable rung spacing for the ladder cable tray must be 9 inches; where
exposed to direct rays of the sun, you must identify cables as being sunlight
resistant;
(B) Welding cables
installed in dedicated cable trays;
(C) Single conductors used as equipment
grounding conductors; these conductors, which may be insulated, covered, or
bare, must be No. 4 or larger; and
(D) Multiconductor cable, Type MV; where
exposed to direct rays of the sun, you must identify the cable as being
sunlight resistant.
(iii) Metallic cable trays may be used as
equipment grounding conductors only where continuous maintenance and
supervision ensure that qualified persons will service the installed cable tray
system.
(iv) Cable trays in
hazardous (classified) locations may contain only the cable types permitted in
such locations. (See WAC
296-24-95711.)
(v) Cable tray systems may not be used in
hoistways or where subjected to severe physical damage.
(d)
Open wiring on insulators.
(i) Open wiring on insulators is only
permitted on systems of 600 volts, nominal, or less for industrial or
agricultural establishments, indoors or outdoors, in wet or dry locations,
where subject to corrosive vapors, and for services.
(ii) You must rigidly support conductors
smaller than No. 8 on noncombustible, non-absorbent insulating materials and
may not contact any other objects. You must install supports as follows:
(A) Within 6 inches from a tap or
splice;
(B) Within 12 inches of a
dead-end connection to a lamp-holder or receptacle; and
(C) At intervals not exceeding 4 feet 6
inches, and at closer intervals sufficient to provide adequate support where
likely to be disturbed.
(iii) In dry locations, where not exposed to
severe physical damage, conductors may be separately enclosed in flexible
nonmetallic tubing. The tubing must be in continuous lengths not exceeding 15
feet and secured to the surface by straps at intervals not exceeding 4 feet 6
inches.
(iv) You must separate open
conductors from contact with walls, floors, 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, you must insert a
waterproof sleeve of nonconductive material in the hole and an insulating
bushing slipped into the sleeve at each end in such a manner as to keep the
conductors absolutely out of contact with the sleeve. You must carry each
conductor through a separate tube or sleeve.
(v) Where open conductors cross ceiling
joints and wall studs and are exposed to physical damage (for example, located
within 7 feet of the floor), you must protect them.
(2)
Cabinets, boxes, and
fittings.
(a)
Conductors
entering boxes, cabinets, or fittings.
(i) You must protect conductors entering
cutout boxes, cabinets, or fittings from abrasion, and you must effectively
close openings through which conductors enter.
(ii) You must effectively close unused
openings in cabinets, boxes, and fittings.
(iii) Where cable is used, you must secure
each cable to the cabinet, cutout box, or meter socket enclosure. However,
where cable with an entirely nonmetallic sheath enters the top of a
surface-mounted enclosure through one or more nonflexible raceways not less
than 18 inches or more than 10 feet in length, the cable need not be secured to
the cabinet, box, or enclosure provided all of the following conditions are
met:
(A) Each cable is fastened within 12
inches of the outer end of the raceway, measured along the sheath;
(B) The raceway extends directly above the
enclosure and does not penetrate a structural ceiling;
(C) A fitting is provided on each end of the
raceway to protect the cable from abrasion, and the fittings remain accessible
after installation;
(D) The raceway
is sealed or plugged at the outer end using approved means so as to prevent
access to the enclosure through the raceway;
(E) The cable sheath is continuous through
the raceway and extends into the enclosure not less than 0.25 inches beyond the
fitting;
(F) The raceway is
fastened at its outer end and at other points as necessary; and
(G) Where installed as conduit or tubing, the
allowable cable fill does not exceed that permitted for complete conduit or
tubing systems.
(b)Covers and canopies.
(i) You must provide all pull boxes, junction
boxes, and fittings with covers identified for the purpose. If metal covers are
used, you must ground them. In completed installations, each outlet box must
have a cover, faceplate, or fixture canopy. You must provide covers of outlet
boxes having holes through which flexible cord pendants pass with bushings
designed for the purpose or they must have smooth, well-rounded surfaces on
which the cords may bear.
(ii)
Where a fixture canopy or pan is used, you must cover any combustible wall or
ceiling finish exposed between the edge of the canopy or pan and the outlet box
with noncombustible material.
(c)Pull and junction boxes for systems
over 600 volts, nominal. In addition to other requirements in this
section, the following requirements apply to pull and junction boxes for
systems over 600 volts, nominal:
(i) Boxes
must provide a complete enclosure for the contained conductors or
cables.
(ii) You must close boxes
by suitable covers securely fastened in place.
Note: Underground box covers that weigh over 100
pounds meet this requirement.
(iii) Covers for boxes must be permanently
marked "HIGH VOLTAGE." The marking must be on the outside of the box cover and
must be readily visible and legible.
(3)
Switches.
(a)Single-throw knife switches.
You must place single-throw knife switches so that gravity will not tend to
close them. You must provide single-throw knife switches approved for use in
the inverted position with a locking device that will ensure that the blades
remain in the open position when so set.
(b)
Double-throw knife switches.
Double-throw knife switches may be mounted so that the throw will be either
vertical or horizontal. However, if the throw is vertical, you must provide a
locking device to ensure that the blades remain in the open position when so
set.
(c)Connection of
switches.
(i) You must connect
single-throw knife switches and switches with butt contacts so that the blades
are deenergized when the switch is in the open position.
(ii) You must connect single-throw knife
switches, molded-case switches, switches with butt contacts, and circuit
breakers used as switches so that the terminals supplying the load are
deenergized when the switch is in the open position. However, blades and
terminals supplying the load of a switch may be energized when the switch is in
the open position where the switch is connected to circuits or equipment
inherently capable of providing a backfeed source of power. For such
installations, you must install a permanent sign on the switch enclosure or
immediately adjacent to open switches that read,
"WARNINGLOAD SIDE TERMINALS MAY BE ENERGIZED BY
BACKFEED."
(d)Faceplates for flush-mounted snap
switches. Snap switches mounted in boxes must have faceplates installed
so as to completely cover the opening and seat against the finished
surface.
(e) You must effectively
ground snap switches, including dimmer switches, and you must provide a means
to ground metal faceplates, whether or not a metal faceplate is installed.
However, if no grounding means exists within the snap-switch enclosure, or
where the wiring method does not include or provide an equipment ground, a snap
switch without a grounding connection is permitted for replacement purposes
only. You must provide such snap switches shall be provided with a faceplate of
nonconducting, noncombustible material if they are located within reach of
conducting floors or other conducting surfaces.
(4)Switchboards and panelboards.
(a)
Switchboards with exposed live
parts. Switchboards that have any exposed live parts must be located in
permanently dry locations and must be accessible only to qualified
persons.
(b)
Panelboard
enclosures. You must mount panelboards in cabinets, cutout boxes, or
enclosures designed for the purpose and they must be dead front. However,
panelboards other than the dead front externally operable type are permitted
where accessible only to qualified persons.
(c)Knife switches mounted in
switchboards or panel-boards. Exposed blades of knife switches mounted
in switchboards or panelboards must be dead when open.
(5)Enclosures for damp or wet
locations.
(a)Cabinets, cutout
boxes, fittings, boxes, and panel-board enclosures. You must install
cabinets, cutout boxes, fittings, boxes, and panelboard enclosures in damp or
wet locations so as to prevent moisture or water from entering and accumulating
within the enclosures and you must mount them so there is at least 0.25 inches
airspace between the enclosure and the wall or other supporting surface.
However, nonmetallic enclosures may be installed without the airspace on a
concrete, masonry, tile, or similar surface. The enclosures must be
weatherproof in wet locations.
(b)Switches, circuit breakers, and
switchboards. You must enclose switches, circuit breakers, and
switchboards installed in wet locations in weatherproof enclosures.
(6)Conductors for general
wiring.
(a)Insulation.
You must insulate all conductors used for general wiring unless otherwise
permitted in this part.
(b)Type. The conductor
insulation must be of a type that is approved for the voltage, operating
temperature, and location of use.
(c)Distinguishable. Insulated
conductors must be distinguishable by appropriate color or other suitable means
as being grounded conductors, ungrounded conductors, or equipment grounding
conductors.
(7)Flexible cords and cables.
(a)Use of flexible cords and
cables.
(i) Flexible cords and cables
must be approved for conditions of use and location.
(ii) Flexible cords and cables may be used
only for:
(A) Pendants;
(B) Wiring of fixtures;
(C) Connection of portable lamps or
appliances;
(D) Portable and mobile
signs;
(E) Elevator
cables;
(F) Wiring of cranes and
hoists;
(G) Connection of
stationary equipment to facilitate their frequent interchange;
(H) Prevention of the transmission of noise
or vibration;
(I) Appliances where
the fastening means and mechanical connections are designed to permit removal
for maintenance and repair;
(J)
Data processing cables approved as a part of the data processing
system;
(K) Connection of moving
parts; and
(L) Temporary wiring as
permitted in subsection (1)(b) of this section.
(iii) If used as permitted in (a)(ii)(C),
(G), or (I) of this subsection, the flexible cord must be equipped with an
attachment plug and must be energized from an approved receptacle
outlet.
(iv) Unless specifically
permitted otherwise in (a)(ii) of this subsection, flexible cords and cables
may 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;
(D) Where
attached to building surfaces;
(E)
Where concealed behind building walls, ceilings, or floors; or
(F) Where installed in raceways, except as
otherwise permitted in this part.
(v) Flexible cords used in show windows and
showcases must be Type S, SE, SEO, SEOO, SJ, SJE, SJEO, SJEOO, SJO, SJOO, SJT,
SJTO, SJTOO, SO, SOO, ST, STO, or STOO, except for the wiring of
chain-supported lighting fixtures and supply cords for portable lamps and other
merchandise being displayed or exhibited.
(b)Identification, splices, and
terminations.
(i) A conductor of a
flexible cord or cable that is used as a grounded conductor or an equipment
grounding conductor must be distinguishable from other conductors. You must
durably mark Types S, SC, SCE, SCT, SE, SEO, SEOO, SJ, SJE, SJEO, SJEOO, SJO,
SJT, SJTO, SJTOO, SO, SOO, ST, STO, and STOO flexible cords and Types G, G-GC,
PPE, and W flexible cables on the surface at intervals not exceeding 24 inches
with the type designation, size, and number of conductors.
(ii) Flexible cords may be used only in
continuous lengths without splice or tap. Hard-service cord and junior
hard-service cord No. 12 and larger may be repaired if spliced so that the
splice retains the insulation, outer sheath properties, and usage
characteristics of the cord being spliced.
(iii) You must connect flexible cords and
cables to devices and fittings so that strain relief is provided that will
prevent pull from being directly transmitted to joints or terminal
screws.
(8)Portable cables over 600 volts,
nominal. This subsection applies to portable cables used at more than
600 volts, nominal.
(a)
Conductor
construction. Multiconductor portable cable for use in supplying power
to portable or mobile equipment at over 600 volts, nominal, must consist of No.
8 or larger conductors employing flexible stranding. However, the minimum size
of the insulated ground-check conductor of Type G-GC cables must be No.
10.
(b)Shielding. You
must shield cables operated at over 2,000 volts for the purpose of confining
the voltage stresses to the insulation.
(c)Equipment grounding
conductors. You must provide grounding conductors.
(d)
Grounding shields. You must
ground all shields.
(e)
Minimum bending radii. The minimum bending radii for portable
cables during installation and handling in service must be adequate to prevent
damage to the cable.
(f)Fittings. Connectors used to
connect lengths of cable in a run must be of a type that lock firmly together.
You must make provisions to prevent opening or closing these connectors while
energized. You must provide strain relief at connections and
terminations.
(g)
Splices. Portable cables may not be operated with splices unless
the splices are of the permanent molded, vulcanized, or other approved
type.
(h)
Terminations. You must suitably mark termination enclosures with a
high voltage hazard warning, and terminations must be accessible only to
authorized and qualified employees.
(9)Fixture wires.
(a)General. Fixture wires must
be approved for the voltage, temperature, and location of use. You must
identify a fixture wire which is used as a grounded conductor.
(b)Uses permitted. Fixture wires
may be used only:
(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 may not be used as branch-circuit conductors except as permitted for
Class 1 power limited circuits and for fire alarm circuits.
(10)
Equipment for general
use.
(a)Lighting fixtures,
lampholders, lamps, and receptacles.
(i) Fixtures, lampholders, lamps, rosettes,
and receptacles may have no live parts normally exposed to employee contact.
However, rosettes and cleat-type lampholders and receptacles located at least 8
feet above the floor may have exposed terminals.
(ii) Handlamps of the portable type supplied
through flexible cords must be equipped with a handle of molded composition or
other material identified for the purpose, and a substantial guard must be
attached to the lampholder or the handle. Metal shell, paper-lined lampholders
may not be used.
(iii) Lampholders
of the screw-shell type must be installed for use as lampholders only. Where
supplied by a circuit having a grounded conductor, the grounded conductor must
be connected to the screw shell. Lampholders installed in wet or damp locations
must be of the weatherproof type.
(iv) Fixtures installed in wet or damp
locations must be identified for the purpose and must be so constructed or
installed that water cannot enter or accumulate in wireways, lampholders, or
other electrical parts.
(b)
Receptacles, cord connectors, and
attachment plugs (caps).
(i) All 15-
and 20-ampere attachment plugs and connectors must be constructed so that there
are no exposed current-carrying parts except the prongs, blades, or pins. The
cover for wire terminations must be a part that is essential for the operation
of an attachment plug or connector (dead-front construction). You must install
attachment plugs so that their prongs, blades, or pins are not energized unless
inserted into an energized receptacle. No receptacles may be installed so as to
require an energized attachment plug as its source of supply.
(ii) Receptacles, cord connectors, and
attachment plugs must 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.
(iii) Nongrounding-type
receptacles and connectors may not be used for grounding-type attachment
plugs.
(iv) A receptacle installed
in a wet or damp location must be suitable for the location.
(v) A receptacle installed outdoors in a
location protected from the weather or in other damp locations must have an
enclosure for the receptacle that is weatherproof when the receptacle is
covered (attachment plug cap not inserted and receptacle covers closed).
Note: A receptacle is considered to be in a
location protected from the weather when it is located under roofed open
porches, canopies, marquees, or the like and where it will not be subjected to
a beating rain or water runoff.
(vi) A receptacle installed in a wet location
where the product intended to be plugged into it is not attended while in use
(for example, sprinkler system controllers, landscape lighting, and holiday
lights) must have an enclosure that is weatherproof with the attachment plug
cap inserted or removed.
(vii) A
receptacle installed in a wet location where the product intended to be plugged
into it will be attended while in use (for example, portable tools) must have
an enclosure that is weatherproof when the attachment plug cap is
removed.
(c)Appliances.
(i) Appliances may have no live parts
normally exposed to contact other than parts functioning as open-resistance
heating elements, such as the heating elements of a toaster, which are
necessarily exposed.
(ii) Each
appliance must have a means to disconnect it from all ungrounded conductors. If
an appliance is supplied by more than one source, you must group and identify
the disconnecting means.
(iii) You
must provide each electric appliance with a nameplate giving the identifying
name and the rating in volts and amperes, or in volts and watts. If the
appliance is to be used on a specific frequency or frequencies, you must mark
it so. Where motor overload protection external to the appliance is required,
the appliance shall be so marked.
(iv) You must locate marking so as to be
visible or easily accessible after installation.
(d)Motors. This subsection
applies to motors, motor circuits, and controllers.
(i) If specified that one piece of equipment
must be "within sight of" another piece of equipment, the piece of equipment
must be visible and not more than 50 feet from the other.
(ii) You must provide an individual
disconnecting means for each controller. You must locate a disconnecting means
within sight of the controller location. However, a single disconnecting means
may be located adjacent to a group of coordinated controllers mounted adjacent
to each other on a multimotor continuous process machine. 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 that is
to be locked in the open position.
(iii) The disconnecting means must disconnect
the motor and the controller from all ungrounded supply conductors and must be
so designed that no pole can be operated independently.
(iv) The disconnecting means must plainly
indicate whether it is in the open (off) or closed (on) position.
(v) The disconnecting means must be readily
accessible. If more than one disconnect is provided for the same equipment,
only one need be readily accessible.
(vi) You must provide an individual
disconnecting means for each motor, but a single disconnecting means may be
used for a group of motors under any one of the following conditions:
(A) If a number of motors drive several parts
of a single machine or piece of apparatus, such as a metal or woodworking
machine, crane, or hoist;
(B) If a
group of motors is under the protection of one set of branch-circuit protective
devices; or
(C) If a group of
motors is in a single room within sight of the location of the disconnecting
means.
(vii) You must
protect motors, motor-control apparatus, and motor branch-circuit conductors
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.
(viii) 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, you must provide
suitable insulating mats or platforms so that the attendant cannot readily
touch live parts unless standing on the mats or platforms.
(e)
Transformers.
(i) This subsection covers the installation
of all transformers except the following:
(A)
Current transformers;
(B) Dry-type
transformers installed as a component part of other apparatus;
(C) Transformers that 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-alarm circuits; and
(E) Liquid-filled or dry-type transformers
used for research, development, or testing, where effective safeguard
arrangements are provided.
(ii) You must indicate the operating voltage
of exposed live parts of transformer installations by signs or visible markings
on the equipment or structure.
(iii) Dry-type, high fire point
liquid-insulated, and askarel-insulated transformers installed indoors and
rated over 35 kV must be in a vault.
(iv) You must install oil-insulated
transformers indoors in a vault.
(v) You must safeguard combustible material,
combustible buildings and parts of buildings, fire escapes, and door and window
openings from fires that may originate in oil-insulated transformers attached
to or adjacent to a building or combustible material.
(vi) Transformer vaults must be constructed
so as to contain fire and combustible liquids within the vault and to prevent
unauthorized access. Locks and latches must be so arranged that a vault door
can be readily opened from the inside.
(vii) Any pipe or duct system foreign to the
electrical installation may not enter or pass through a transformer vault.
Note: Piping or other facilities provided for
vault fire protection, or for transformer cooling, are not considered foreign
to the electrical installation.
(viii) Material may not be stored in
transformer vaults.
(f)Capacitors.
(i) You must provide all capacitors, except
surge capacitors or capacitors included as a component part of other apparatus,
with an automatic means of draining the stored charge after the capacitor is
disconnected from its source of supply.
(ii) The following requirements apply to
capacitors installed on circuits operating at more than 600 volts, nominal:
(A) You must use group-operated switches for
capacitor switching and they must be capable of the following:
(I) Carrying continuously not less than 135 %
of the rated current of the capacitor installation;
(II) Interrupting the maximum continuous load
current of each capacitor, capacitor bank, or capacitor installation that will
be switched as a unit;
(III)
Withstanding the maximum inrush current, including contributions from adjacent
capacitor installations; and
(IV)
Carrying currents due to faults on the capacitor side of the switch;
(B) You must install a means to
isolate from all sources of voltage each capacitor, capacitor bank, or
capacitor installation that will be removed from service as a unit. The
isolating means must provide a visible gap in the electric circuit adequate for
the operating voltage;
(C)
Isolating or disconnecting switches (with no interrupting rating) must be
interlocked with the load interrupting device or you must provide it with
prominently displayed caution signs to prevent switching load current;
and
(D) For series capacitors, you
must ensure the proper switching 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.
(g)Storage
batteries. You must make provisions for sufficient diffusion and
ventilation of gases from storage batteries to prevent the accumulation of
explosive mixtures.