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(continued)
(Title 24, Part 3, Section 3-710-84(a).)
(b) Vertical Clearances. All conductors of outside wiring shall comply with clearances specified in Rule 37, General Order No. 95, 1981 Edition, Rules for Overhead Electric Line Construction of the California Public Utilities Commission, which is hereby incorporated by reference. The following table for overhead conductors and sign clearances is extracted from Tables 1 and 2A of these rules:
Minimum Clearance
__________________________
Overhead Conductors 750- Over
Nature of Vertical Clearance 20,000 volts 20,000 volts
1. Above tracks of railroads which
transport freight cars where not operated
by overhead
contact wires............................... 28 feet 34 feet
2. Above tracks of railroads operated by
overhead contact wires 30 feet 34 feet 3.
Above and along thoroughfares in urban areas
and above thoroughfares in rural areas...... 25 feet 30 feet
4. Above areas (other than thoroughfares)
where it is possible to drive vehicles...... 25 feet 30 feet
5. Above areas accessible to pedestrians
only........................................ 17 feet 25 feet
6. Above structures............................ 12 feet 12 feet
7. Vertical clearance above all signs upon
which men can walk.......................... 12 feet 12 feet
8. Vertical clearance above all signs upon
which men cannot walk....................... 8 feet 8 feet
9. Vertical clearance under signs.............. Prohibited Prohibited
10. Horizontal clearance from signs............. 6 feet 6 feet
(Title 24, Part 3, Section 3-710-85(a).)
(c) Clearance from Buildings. Open high-voltage conductors shall be substantially supported independently of buildings or structures and shall have a clearance from buildings or structures as follows:
(1) They shall be maintained not less than 6 feet horizontally from buildings or other structures or any portion thereof. Where the vertical distance above ground of conductors of 7,500 volts or less is in excess of 35 feet, this horizontal clearance from buildings shall be permitted to be less than 6 feet, but shall be not less than 4 feet.
(2) They shall be kept not less than 12 feet vertically above any part of buildings or structures over which they pass.
(3) High-voltage conductors shall be permitted to be attached to a building at only one point, and shall be suitably guarded against accidental contact. There shall be not more than 3 feet of open conductor between the point of attachment and the point where the conductor enters the conduit or is connected to a bushing.
(4) A conspicuous and permanent "HIGH VOLTAGE" sign shall be placed on the outside at the point where a high-voltage conductor enters the building. Where the conductors are not in conduit, a similar sign shall be placed on the inside of the building also, at the point of entrance.
(Title 24, Part 3, Section 3-710-85(b).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2825. Outdoor Lighting.
Location of Lamps. Lamps for outdoor lighting shall, where practicable, be located below all energized high-voltage conductors, transformers, or other electrical equipment. Adequate clearance shall be provided for relamping operations.
(Title 24, Part 3, Section 3-710-86(b).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2826. Raceways Above Ground.
(a) Protection Against Corrosion. Raceways and equipment, unless constructed of corrosion-resistant material, shall be suitably protected against corrosion inside and outside (except threads at joints).
(Title 24, Part 3, Section 300-6.)
(b) Secured in Place. Raceways shall enter and be secured to pull boxes, terminal enclosures and to cases, shields or enclosures of apparatus, except in vaults, substations or the space under high-voltage switchboards. Raceways shall be securely supported.
(Title 24, Part 3, Section 300-11.)
(c) Protection Against Weather. Raceways exposed to the weather shall be weatherproof.
(Title 24, Part 3, Section 110-11.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2827. Raceways (or Ducts) Below Ground.
(a) Protection Against Physical Damage. Underground ducts of rigid metallic steel conduit, Schedule 80 PVC conduit, or equivalent, containing cables operating at a potential above 35,000 volts, shall be installed at a depth of at least 36 inches. A lesser depth is permitted for ducts containing cables operating at 35,000 volts or less, if the duct is rigid metallic conduit, Schedule 80 PVC conduit, or equivalent, or if the duct has a layer of concrete at least 3 inches thick above the duct.
Exception: No. 1: Direct buried conduits to contain cables for series street lighting circuits operating at less than 7,500 volts shall be installed at a depth of at least 24 inches below the surface under which they are located.
Exception: No. 2: Where it is impractical to obtain the depth of cover specified, the depth shall be permitted to be reduced, provided that the duct has sufficient strength itself or adequate protection is installed above the duct to prevent damage to the duct system by any surface traffic.
(Title 24, Part 3, Section 3-710-3(b).)
(b) Protection Against Corrosion. Metallic underground ducts shall be suitably protected from corrosion.
(Title 24, Part 3, Section 300-6.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2828. Risers.
(a) Pole-Supported Risers. Conductors installed in the form of lateral or vertical runs or risers supported by poles shall conform to the provisions of Rule 54.6, General Order No. 95, 1981 Edition, Rules for Overhead Electric Line Construction of the California Public Utilities Commission, wherein such conductors are specifically treated, and which is hereby incorporated by reference
(Title 24, Part 3, Section 3-710-3(b)5A.)
(b) Structure-Supported Risers (Risers Not Covered in (a) above.) Risers installed outdoors on structures other than poles or installed indoors shall comply with the following:
(1) Riser conductors shall be protected from physical damage by grounded rigid metallic conduit, Schedule 80 PVC conduit, or U-shaped moldings, or equivalent, from the ground line to a minimum height of 8 feet. Suitable protection shall be continued to within 2 feet of the terminal.
(2) The riser terminal and exposed cables at the terminal shall be suitably guarded or isolated.
(3) Risers and protective covering shall be securely supported by means of corrosion-resistant straps at intervals not exceeding 3 feet.
(4) Metallic conduit risers shall be effectively grounded. Adjacent metallic conduit risers shall be bonded together.
(Title 24, Part 3, Section 3-710-3(b)5B.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2829. Terminal Enclosures.
(a) Accessible. Terminal enclosures shall be so installed that the wiring within is readily accessible.
(b) Covers. Terminal enclosures shall be effectively closed by suitable covers, mechanically secured against unauthorized entry.
(c) Size. The dimensions of terminal enclosures shall be adequate to permit the minimum bending radii of the cables installed therein.
(d) Protection. Terminal enclosures shall be of corrosion-resistant and fire-resistant material. Terminal enclosures and their covers must be able to withstand the structural loading to which they may be subjected.
(e) Number of Conductors. The number of conductors installed in any terminal enclosure shall be compatible with safe working practice.
(f) Identification. The covers of all terminal enclosures shall be posted with a permanent "HIGH VOLTAGE" warning sign having letters at least 1/2 inch high.
(Title 24, Part 3, Section 3-710-87.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2830. Insulated Conductors.
(a) General. Insulated cables shall be of a type suitable for the voltage and service conditions. All cables installed underground shall have a grounded metallic sheath, shield, or a bare concentric grounded conductor, or shall be installed in grounded metallic conduit.
(Title 24, Part 3, Section 3-710-88(a).)
(b) Cable Installed in Buildings. Where installed in buildings, cables energized above 35,000 volts shall be encased in at least 3 inches of concrete or equivalent fire-resistant material.
(Title 24, Part 3, Section 3-710-88(c).)
(c) Direct Buried Cables. Direct buried cables or cables in flexible nonmetallic enclosures shall be installed at a depth of at least 36 inches. Lesser depths shall be permitted to be employed if the cable is armored with a minimum of No. 12 BWG steel wire closely wound or two layers of steel tape each at least 0.020 inch thick, or if the cable is protected by a layer of concrete at least 3 inches thick above the cable.
Exception: Lesser depths than those listed are permitted where cables rise for terminations and splices or where access is otherwise required.
(Title 24, Part 3, Section 3-710-88(c).)
(d) Identification. Cables shall be labeled at all circuit terminals, sectionalizing points, vaults, rooms, etc. The labels shall, as a minimum, show phase and circuit designation and nearest sectionalizing points.
(1) Changes in labeling shall be made concurrently with changes in circuit.
(Title 24, Part 3, Section 3-710-88(d).)
(e) Neutral Conductor. The size and insulation of neutral conductors shall be in accordance with Section 2818.
(Title 24, Part 3, Section 3-710-88(e).)
(f) Shielding. All cables normally operated above 5,000 volts shall have insulation shielding, except that shielding shall not be required for series street lighting circuits operating at less than 7,500 volts. Metallic shielding at terminations shall be effectively grounded. If shielding is sectionalized, each section shall be effectively grounded.
(Title 24, Part 3, Section 3-310-61.)
(g) Terminations. Cable terminations shall be suitable for the voltage and service conditions.
(Title 24, Part 3, Section 3-710-3(c).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2831. Circuit Feedback.
(a) Identification. Circuits shall be labeled at all accessible points with suitable warning signs stating the locations from which feedback may occur because of:
(1) Circuits energized by manually or automatically operated equipment, or
(2) Circuit configurations or connections, or
(3) Circuits feeding a load which can be connected to auxiliary generating equipment, or
(4) Circuits feeding synchronous motor-driven generator sets which can be energized by reverse power flow from batteries or other sources.
(Title 24, Part 3, Section 3-710-89.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
(Formerly Article 69)
s 2833. Interrupter Switches.
(a) Rating.
(1) Continuous Current Rating. The continuous current rating of interrupter switches shall equal or exceed the maximum continuous current at the point of installation.
(2) Interrupting Rating. The current interrupting rating of interrupter switches shall equal or exceed the maximum current which the switch will be required to interrupt.
(3) Momentary Rating. The momentary rating of interrupter switches shall equal or exceed the asymmetrical short circuit current available at the switch location. The asymmetrical short circuit current shall include contributions from all connected sources of energy, such as other lines, generators, large motors, etc.
(4) Fault Closing Rating. Interrupter switches shall have a fault closing rating equal to or greater than the asymmetrical short circuit current which can occur at the switch location, unless suitable interlocks or operating procedures preclude the possibility of closing into a fault.
(5) Voltage Rating. The maximum voltage rating of interrupter switches shall equal or exceed the maximum circuit voltage.
(b) Enclosure. Interrupter switches installed indoors shall have a metal enclosure, or shall be installed in a room of at least 2-hour fire-resistive construction, or in a transformer vault.
(c) Installation Requirements. Interrupter switches shall be so installed that the center of the grip of the operating handle of the switch, when in its uppermost position, will be not more than 6 1/2 feet above the floor or working platform.
(d) Enclosures as Raceways. Switch enclosures shall not be used as raceways for conductors feeding through, or tapping off, to other switches, unless adequate space is provided for this purpose.
(e) Switching of Conductors. The switching mechanism shall be arranged to be operated from a location where the operator is not exposed to energized parts and shall be arranged to open all ungrounded conductors of the circuit simultaneously with one operation. Switches shall be arranged to be locked in the open position. Metal-enclosed switches shall be operable from outside the enclosure.
(f) Knife Switches. All knife switch blades shall be de-energized when the switch is in the open position.
Exception: The blades of switches used to connect a load to more than one source of supply shall be permitted to be energized when in the open position if (1) suitable barriers or enclosures are installed over the switches to prevent accidental contact with the energized switch blades; and (2) a conspicuous permanent sign is placed on the outside of the barrier or enclosure warning that the switch blades may be energized in any position.
(g) Fuses. Fuses installed with interrupter switches shall comply with the requirements of Article 24.
(h) Readily and Safely Accessible. Interrupter switches, except those installed on poles or structures, shall be so located that they may be operated or maintained from a readily and safely accessible place.
(i) Identification. Interrupter switches shall have a permanent and legible nameplate including the following information: manufacturer's type or designation, continuous current rating, interrupting current rating, momentary current rating, fault closing rating, and maximum voltage rating.
(j) Stored Energy for Opening. The stored energy operator shall be permitted to be left in the uncharged position after the switch has been closed if a single movement of the operating handle charges the operator and opens the switch.
(Title 24, Part 3, Section 3-710-21(e).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2834. Fused Interrupter Switches.
(a) Fused interrupter switches shall be so installed that all supply terminals shall be at the top of the switch enclosure.
Exception: Supply terminals are not required to be at the top of the switch enclosure if barriers are installed to prevent persons from accidentally contacting energized parts or dropping tools or fuses into energized arts.
(b) Where fuses can be energized by backfeed, a sign shall be placed on the enclosure door reading, "WARNING -FUSES MAY BE ENERGIZED BY BACKFEED."
(Title 24, Part 3, Section 710-24(o).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2835. Disconnecting (Isolating) Switches.
(a) General. Disconnecting switches shall be permitted to be single-pole or multiple-pole.
(b) Isolating Means. A suitable air break switching device shall be installed to isolate each oil switch or group of oil switches from all sources of supply unless automatic disconnecting switchgear equipment of the metal-clad draw-out type is used.
Exception: In highly corrosive or flammable atmospheres, suitable isolating means other than air break shall be used, or the isolating means shall be installed in an enclosure approved for use in such locations of the particular hazard involved.
(c) Accessible to Qualified Persons Only. Disconnecting switches installed in locations where only qualified persons are permitted access shall be installed in suitable enclosures, or shall be elevated above the floor not less than clearances shown in Section 2934.
(d) Accessible to Other Than Qualified Persons. Disconnecting switches installed in any location where other than qualified persons have access shall be installed in suitable enclosures.
The door or cover of the enclosure shall be kept closed, except when opened for operation or inspection. If installed so that the bottom of the enclosure is less than 8 feet above the floor, the door or cover shall be kept locked.
When disconnecting switches are operable from outside the enclosure by a remote control mechanism, the operating handle or lever shall be kept locked when in either the open or closed position.
(e) Operation. Isolating switches shall be provided with suitable means for safe normal operation. This operating means shall be permitted to be an insulated hookstick, an insulated external operating handle, or remote control mechanism. Disconnecting switches shall provide a visible gap in the circuit adequate for the operating voltage.
Provision shall be made to observe the position of the blades of disconnecting switches. If viewing windows are provided, they shall be shatterproof, of adequate size, and suitably located to permit viewing of all contacts. Metal-enclosed switches other than those designed for hookstick operation shall be arranged to be locked in the open position. Multiple switches in the same enclosure shall be equipped with a connection diagram.
(f) Rating. Disconnecting switches shall have current and voltage ratings not less than the full-load current and operating voltage of the circuit. The momentary rating of disconnecting switches shall equal or exceed the asymmetrical short circuit current available at the switch location. The asymmetrical short circuit current shall include contributions from all connected sources of energy, such as other lines, generators, large motors, etc.
(g) Identification. The disconnecting switches shall have a permanent and legible nameplate including the following information: continuous current rating, maximum voltage rating, momentary current rating.
(h) Warning Signs. Unless so interlocked that they cannot be opened under load, disconnecting switches shall be provided with permanent warning signs having letters at least 2 inches high and reading as follows: "Warning -Disconnecting Switch -Do Not Open Under Load." When a group of disconnecting switches is installed in one room or enclosure, a single sign may be sufficient.
(i) Barriers. Suitable barriers shall be installed on both sides of each pole of disconnecting switches mounted indoors.
(Title 24, Part 3, Section 3-710-22.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
(Formerly Article 70)
s 2837. Ratings.
(a) The continuous current rating of a circuit breaker shall equal or exceed the maximum continuous current at the point of installation.
(b) The interrupting rating of a circuit breaker shall equal or exceed the maximum fault current the circuit breaker will be required to interrupt, including contributions from all connected sources of energy.
(c) The closing rating of a circuit breaker shall equal or exceed the maximum asymmetrical fault current into which the circuit breaker can be closed.
(d) The momentary rating of a circuit breaker shall equal or exceed the maximum asymmetrical fault current at the point of installation.
(e) The rated maximum voltage of a circuit breaker shall equal or exceed the maximum circuit voltage.
(Title 24, Part 3, Section 710-21(a)(5)-(a)(9).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2838. Grounding.
Metallic enclosures for circuit breakers shall be grounded as required by Article 6.
(Title 24, Part 3, Section 3-710-21(a)(10).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2839. General.
Circuit breakers shall comply with all the provisions of American National Standard ANSI/IEEE C37.04 -1979, Rating Structure for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis, which is hereby incorporated by reference, and shall be permitted to be single pole or multi-pole. They shall:
(a) Have an accessible mechanical or other approved means for manual tripping, independent of control power.
(b) Be release free (trip free).
(c) Have positive means to prevent unintended operation during inspection or maintenance.
(d) When operated manually while energized, open and close the main contacts independent of the speed of the manual operation.
(e) Be equipped with a mechanical position indicator to show the open or closed position of the main contacts.
(Title 24, Part 3, Section 710-21 (a) (4) a-e.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2840. Identification.
(a) Circuit breakers shall have a permanent and legible nameplate including the following information: manufacturer's name or trademark, manufacturer's type or identification number, continuous current rating, interrupting rating in MVA or amperes, and maximum voltage rating.
(b) Modifications of a circuit breaker affecting its rating(s) shall be accompanied by an appropriate change in the identification data on the nameplate.
(Title 24, Part 3, Section 710-21(a)(4)f.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2841. Isolation.
(a) Means shall be provided to isolate each circuit breaker or circuit breaker installation from all sources of potential.
(b) The isolating means shall provide a visible gap in the electrical circuit adequate for the operating voltage.
(c) Isolating or disconnecting switches (with no interrupting rating) shall be mechanically interlocked with the circuit breaker or shall be provided with prominently displayed caution signs in accordance with Section 2835 to prevent switching load current.
(d) The isolating means shall be permitted to be individually or group operated.
(Title 24, Part 3, Section 3-710-21(a)(11).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
(Formerly Article 71)
s 2843. General.
Automatic circuit reclosers shall comply with all the provisions of American National Standard ANSI/IEEE C37.60-1981, Requirements for Overhead, Pad Mounted, Dry Vault, and Submersible Automatic Circuit Reclosers and Fault Interrupters for AC Systems, which is hereby incorporated by reference, and with all the requirements of Article 21, except that the provisions of ANSI/IEEE C37.04-1979 referenced in Article 21 do not apply to circuit reclosers.
(Title 24, Part 3, Section 3-710-21(d)(9).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
(Formerly Article 72)
s 2845. Power Fuses.
(a) Use. Where fuses are used to protect conductors and equipment, a fuse shall be placed in each ungrounded conductor.
(1) Parallel (Multiple) Power Fuses. Two power fuses shall be permitted to be used in parallel (multiple) to protect the same load, provided:
(A) Both fuses have identical ratings, and
(B) Both fuses are installed in a common mounting with electrical connections that will divide the current equally.
(b) Vented Power Fuses. Power fuses of the vented type shall not be used indoors, underground or in metal enclosures unless identified for the use.
(c) Interrupting Rating. The interrupting rating of power fuses shall equal or exceed the maximum fault current the fuse will be required to interrupt, including contributions from all connected sources of energy.
(d) Voltage Rating. The maximum voltage rating of power fuses shall equal or exceed the maximum circuit voltage. Fuses having a minimum recommended operating voltage shall not be applied below this voltage.
(e) Installation. Fuses shall be installed in suitable metal enclosures.Exception: Fuses shall be permitted to be installed without metal enclosures in substations, vaults, or outdoor locations.
(f) Structure Mounted Indoor or Outdoor. The height of fuse mountings on structures shall provide safe clearance between lowest energized part (open or closed position) and standing surface. For mounting heights, see Article 35.
(g) Disconnecting Means. A suitable means shall be installed to isolate each fuse from all sources of potential. Provision for installation and removal of the fuse by suitable live line tools meets this requirement.
(h) Identification of Fuse Mountings and Fuse Units. The fuse mountings and fuse units shall be permanently and legibly identified to include the following information: manufacturer's type or designation, continuous current rating, interrupting current rating, and maximum voltage rating.
(i) Clear Workspace. Space shall be provided for fuse handling in accordance with Article 35.
(j) Door Interlock. Means shall be provided to prevent access to fuses installed in metal enclosures until all sources of energy are disconnected.
(k) Enclosed Fuse Types. Fuses installed in metal enclosures shall be of the non-vented or controlled-vented type. Adequate volume or other means shall be provided to prevent the operation of fuses from causing dangerous pressures in enclosures.
( l) Fused cutouts installed in buildings or transformer vaults shall be of a type approved for the purpose. They shall be readily accessible for fuse replacement.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
(Formerly Article 73)
s 2847. Distribution Cutouts and Fuse Links -Expulsion Type.
(a) Installation. The cutouts shall be so located that they may be readily and safely operated and refused, and so that the exhaust of the fuses will not endanger persons. Distribution cutouts shall not be used indoors, underground, or in metal enclosures.
(Title 24, Part 3, Section 710-21(c)(1).)
(b) Interrupting Rating. The interrupting rating of distribution cutouts shall equal or exceed the maximum fault current which can occur at the fuse location. The available fault current at the fuse location shall include contributions from all connected sources of energy, such as the other lines, generators, large motors, etc.
(Title 24, Part 3, Section 710-21(c)(3).)
(c) Voltage Rating. The maximum voltage rating of cutouts shallequal or exceed the maximum circuit voltage.
(Title 24, Part 3, Section 710-21(c)(4).)
(d) Operation. Where fused cutouts are not suitable to interrupt the circuit manually while carrying full load, an approved means shall be installed to interrupt the entire load.
Unless the fused cutouts are interlocked with the switch to prevent opening of the cutouts under load, a conspicuous sign shall be placed at such cutouts reading, "Warning -Do Not Open Under Load."
(Title 24, Part 3, Section 710-21(c)(2).)
(e) Identification. Distribution cutouts and fuse links shall have a permanent and legible nameplate or identification including the following information:
(1) Cutout Body, Door, or Fuse Tube. Manufacturer's type or designation, continuous current rating, maximum voltage rating, interrupting rating.
(Title 24, Part 3, Section 710-21(c)(5).)
(2) Fuse Links. Continuous current rating, type identification following the continuous current rating.
(Title 24, Part 3, Section 710-21(c)(6).)
(f) Structure Mounted Outdoors. The height of cutouts mounted outdoors on structures shall provide safe clearance between lowest energized parts (open or closed position) and standing surfaces. For mounting heights, see Articles 19 and 35.
(Title 24, Part 3, Section 710-21(c)(7).)
(g) Clear Workspace. Space shall be provided for fuse handling in accordance with Article 35.
(Title 24, Part 3, Section 3-710-21(c)(8).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
(Formerly Article 74)
s 2849. Continuous Current Rating.
The continuous current rating of oil-filled cutouts shall equal or exceed the maximum continuous current at the point of installation.
(Title 24, Part 3, Section 710-21(d)(1).
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2850. Interrupting Rating.
The interrupting rating of oil-filled cutouts shall equal or exceed the maximum fault current available at the cutout location, including contributions from all connected sources of energy, such as other lines, generators, large motors, etc.
(Title 24, Part 3, Section 710-21(d)(2).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 189243(c), Health and Safety Code.
s 2851. Voltage Rating.
The maximum voltage rating of oil-filled cutouts shall equal or exceed the maximum circuit voltage.
(Title 24, Part 3, Section 710-21 (d)(3).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2852. Fault Closing Rating.
Oil-filled cutouts shall have a fault closing rating equal to or greater than the available fault current which can occur at the cutout location, unless suitable interlocks or operating procedures preclude the possibility of closing into a fault.
(Title 24, Part 3, Section 710-21(d)(4).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2853. Location.
The cutouts shall be so located that they will be readily and safely accessible for refusing, with the top of the cutout not more than 5 feet above the floor or platform.
(Title 24, Part 3, Section 710-21(d)(7).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2854. Identification.
Oil-Filled Cutouts. Oil-filled cutouts shall have a permanent and legible nameplate showing the rated continuous current, rated maximum voltage, and rated interrupting current.
(Title 24, Part 3, Section 710-21(d)(5).)
(b) Fuses. Fuse links shall have a permanent and legible identification showing the rated continuous current.
(Title 24, Part 3, Section 710-21(d)(6).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 2855. Enclosure.
Suitable barriers or enclosures shall be provided to prevent contact with non-shielded cables or energized parts of oil-filled cutouts.
(Title 24, Part 3, Section 710-21(d)(8).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
(Formerly Article 75)
s 2857. Scope.
This article covers assemblies of metal-enclosed power switchgear and industrial control, including but not limited to switches, interrupting devices and their control, metering, protection and regulating equipment, when an integral part of the assembly, with associated interconnections and supporting structures. This article also includes metal-enclosed power switchgear assemblies which form a part of unit substations, power centers, or similar equipment.
(Title 24, Part 3, Section 710-24(a).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2858. Metal-Enclosed Power Switchgear.
(a) Metal-enclosed power switchgear assemblies shall be constructed in accordance with American National Standard ANSI/IEEE C.37.20-1969 and supplements to and including C37.20d-1978, Switchgear Assemblies Including Metal-Enclosed Bus, which is hereby incorporated by reference.
(b) Metal-enclosed industrial control assemblies shall be constructed in accordance with American National Standard ANSI/NEMA ICS 2-1978, Standards for Industrial Control Devices, Controllers and Assemblies, which is hereby incorporated by reference.
(Title 24, Part 3, Section 3-710-24(q).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2859. Arrangement of Devices in Assemblies.
Arrangement of devices in assemblies shall be such that individual components can safely perform their intended function without adversely affecting the safe operation of other components in the assembly.
(Title 24, Part 3, Section 710-24(b).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2860. Guarding of High-Voltage Energized Parts Within a Compartment.
When access for other than visual inspection is required to a compartment which contains energized high-voltage parts, barriers shall be provided (a) to prevent accidental contact with energized parts, and (b) to prevent tools or other equipment from being dropped on energized parts.
(Title 24, Part 3, Section 710-24(c).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2861. Guarding of Low-Voltage Energized Parts Within a Compartment.
Energized bare parts mounted on doors shall be effectively guarded or enclosed where the door must be opened for maintenance of equipment or removal of drawout equipment.
(Title 24, Part 3, Section 710-24(d).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2862. Clearance for Cable Conductors Entering Enclosure.
The unobstructed space opposite terminals or opposite conduits or other raceways entering a switchgear or control assembly shall be adequate for the type of conductor and method of termination.
(Title 24, Part 3, Section 710-24(e).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2863. Accessibility of Energized Parts.
(a) Doors or removable panels which could provide non-qualified persons access to high-voltage energized parts shall be locked or secured by other approved means. When high-voltage metal-enclosed switchgear or control assemblies are accessible only to qualified persons, bolted-on or hinged and bolted cover plates shall be permitted to be used.
(b) Low-voltage control equipment, relays, motors, and the like (except instrument or control transformers which are connected to the high voltage) shall not be installed in compartments with exposed high-voltage energized parts or high-voltage wiring unless the access door or cover is interlocked with the high-voltage switch or disconnecting means to prevent the door or cover from being opened or removed unless the switch or disconnecting means is in the open position.
(Title 24, Part 3, Section 710-24 (f).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2864. Grounding.
Frames of switchgear and control assemblies shall be grounded in accordance with Article 6.
(Title 24, Part 3, Section 710-24(g).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2865. Grounding of Devices.
Devices with metal cases and/or frames, such as instruments, relays, meters, and instrument and control transformers, located in or on switchgear or control, shall have the frame or case effectively grounded.
(Title 24, Part 3, Section 710-24(h).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2866. Door Stops and Cover Plates.
External hinged doors or covers for outdoor equipment shall be provided with stops to hold them in the open position. Cover plates intended to be removed for inspection of energized parts or wiring shall be locked or secured by other approved means and equipped with lifting handles and shall not exceed 12 square feet in area or 60 pounds in weight. If they exceed 12 square feet in area or 60 pounds in weight, they shall be hinged and bolted or locked.
(Title 24, Part 3, Section 710-24(i).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2867. Gas Discharge from Interrupting Devices.
Gas discharged during operation of interrupting devices shall be so directed as not to endanger personnel.
(Title 24, Part 3, Section 710-24(j).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2868. Inspection Windows.
Windows intended for inspection of disconnecting switches or other devices shall be of suitable transparent material.
(Title 24, Part 3, Section 710-24(k).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2869. Location of Devices.
Control and instrument transfer switch handles or push buttons shall be located in a readily accessible location at an elevation not in excess of 78 inches.
Exception: NO. 1: Operating handles requiring more than 50 pounds of force shall not be higher than 66 inches in either the open or closed position.
Exception: NO. 2: Operating handles for infrequently operated devices, such as drawout fuses, fused potential or control transformers and their primary disconnects, and bus transfer switches, need not be readily accessible, provided they are otherwise safely operable and serviceable from a portable platform.
(Title 24, Part 3, Section 710-24(l ).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2870. Interlocks -Interrupter Switches.
Interrupter switches equipped with stored energy mechanisms shall have mechanical interlocks to prevent access to the switch compartment unless the stored energy mechanism is in the discharged or blocked position.
(Title 24, Part 3, Section 710-24(m).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2871. Interlocks -Circuit Breakers.
(a) Circuit breakers equipped with stored energy mechanisms shall be designed to prevent the release of the stored energy unless the mechanism has been fully charged.
(b) Mechanical interlocks shall be provided in the housing to prevent the complete withdrawal of the circuit breaker from the housing when the stored energy mechanism is in the fully charged position. In lieu of the above interlock, a suitable device may be provided which prevents the complete withdrawal of the circuit breaker until the closing function is blocked.
(Title 24, Part 3, Section 710-24(p).)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
(Formerly Article 76)
s 2873. Scope.
This article applies to the installation of all transformers, including voltage and current regulators or regulating transformers.
Exception: Control, instrument, and other transformers which constitute an integral part of other apparatus (test equipment, X-ray, diathermic, welders, rectifiers, mobile equipment, etc.) and conform to the requirements of such other apparatus.
(Title 24, Part 3, Section 3-450-1.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2874. General.
(a) Ventilation. Adequate ventilation shall be provided to assure safe operating temperature of apparatus.
(Title 24, Part 3, Section 3-450-9.)
(b) Protection from Physical Damage. Transformers and attachments, such as conductors and externally mounted devices, shall be protected from physical damage by suitable barriers, guards, or location.
(Title 24, Part 3, Section 3-450-8(a).)
(c) Identification. Each transformer shall be identified by a permanent nameplate which includes the following information:
(1) The word(s) "Transformer," "Voltage Regulating Transformer," or "Voltage Regulator."
(2) Manufacturer's name, type, and serial designation.
(3) Rated KVA, phases, and frequency.
(4) Voltage ratings and tap voltages.
(5) Connection diagram.
(6) Polarity (single phase).
(7) Impedance.
(8) Rated temperature rise in degrees centigrade.
(9) Identification of insulating medium.
(10) Amount of insulating liquid (not required for sizes 167 KVA and smaller).
(11) Approximate total weight (not required for sizes 25 KVA and smaller).
(Title 24, Part 3, Section 3-450-11.)
(d) Access Openings. Access openings to transformer enclosures shall be provided with a means for locking or otherwise preventing unauthorized access.
(Title 24, Part 3, Section 3-450-13.)
(e) Signs. A permanent, legible, and clearly visible "HIGH VOLTAGE" warning sign, having letters at least 2 inches high, shall be located on the access opening of each transformer enclosure. These signs shall read substantially as follows: "Danger -High Voltage -Keep Out."
(Title 24, Part 3, Section 3-450-14.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2875. Requirements Applicable to Specific Types and Locations of Transformers.
(a) Indoor Installations. Oil-insulated transformers shall not be installed indoors except in a vault constructed in accordance with Sections 2805 and 2806, or a separate building meeting the requirements of Section 2807.
(Title 24, Part 3, Section 3-450-26(a).)
(b) High Fire Point Liquid-Insulated Transformers. Transformers insulated with a listed, less flammable liquid (high fire point) shall be per mitted to be installed without a vault in a non-combustible occupancy area of non-combustible buildings, provided there is a liquid confinement area and the liquid is listed as having a fire point of not less than 300 degrees C. Such transformers installed indoors and rated over 35,000 volts shall be installed in a vault.
(Title 24, Part 3, Section 3-450-23.)
(c) Protection from Flooding. Transformers and associated equipment subject to flooding shall be submersible.
(Title 24, Part 3, Section 3-450-29.)
(d) Protection Against Toxic Gases. Precautions shall be taken to prevent transformers from venting toxic or explosive gases into an inadequately ventilated space.
(Title 24, Part 3, Section 3-450-30.)
(e) Outdoor Installations. Transformers shall be permitted to be installed in outdoor enclosures meeting the requirements of Section 2812 or on roofs in accordance with Section 2808. Transformers installed on poles or structures shall conform to Rule 58.3, General Order No. 95, 1981 Edition, Rules for Overhead Electric Line Construction of the California Public Utilities Commission, which is hereby incorporated by reference. Transformers installed underground shall conform to Rule 34.2C, General Order No. 128, 1974 Edition, Rules for Construction of Underground Electric Supply and Communications Systems of the California Public Utilities Commission which is hereby incorporated by reference
(Title 24, Part 3, Section 3-450-27.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2876. Switching.
Means shall be provided for interrupting the load and magnetizing currents and for isolation of each transformer, transformer bank, or transformer installation. Switches used for these purposes shall be capable of carrying the maximum load current at the point of installation and shall meet the requirements of Article 20.
(a) Load Current. Means shall be installed on either the supply or load side to interrupt the maximum load current of each transformer, transformer bank, or transformer installation that will be switched as a unit. If the load break means is installed on the load side, it may consist of a main transformer switching device or a combination of two or more switching devices carrying the entire transformer load.
(b) Magnetizing Current. Means shall be installed to interrupt the magnetizing current of each voltage regulator, transformer, transformer bank, or transformer installation that will be switched as a unit. Interrupter switches that are not rated to interrupt the maximum load current at the point of installation shall be mechanically interlocked with the load break device required by subsection (a) above.
(c) Isolation. Means shall be installed to isolate from all sources of potential each transformer, transformer bank, or transformer installation that will be removed from service as a unit. Isolating or disconnecting switches that are not rated to interrupt the maximum load current at the point of installation shall be mechanically interlocked with the load break device required by subsection (a) above. If not rated to interrupt magnetizing current,they shall also be interlocked with any separate magnetizing current interrupting switch(es) that may be provided.
Exception: Where such interrupter switches or disconnects are mounted out of doors, a permanent warning sign meeting the requirements of Section 2835 (h) shall be permitted to be provided in lieu of interlocking.
(d) Additional Requirements for Voltage Regulators. Proper switching sequence for regulators shall be assured by use of one of the following:
(1) Mechanically sequenced regulator bypass switch(es).
(2) Mechanical interlocks.
(3) Switching procedure prominently displayed at the switching location.
(Title 24, Part 3, Section 3-450-51.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.
s 2877. Overcurrent Protection.
Each transformer or bank of transformers operating as a unit shall be protected against fault and overload currents by an overcurrent device in each ungrounded conductor in the primary connection. The protective device shall be permitted to be integral with or external to a transformer.
Exception: No. 1: On grounded systems, a relay in each of two phases, in conjunction with a ground relay, meets this requirement.
Exception: No. 2: More than one transformer or transformer bank shall be permitted to be protected by the same overcurrent device, provided the protection for each transformer meets the requirements of Section 2877 (b).
(a) Internal protective devices supplied integrally with a transformer shall be rated or adjusted in accordance with the specifications of the manufacturer.
(b) External protective means shall prevent the flow of current through the transformer in excess of the magnitudes and times in the following table:
Multiples of Transformer Maximum Time
Self-cooled Rating in Seconds8 Times 300 Sec. (continued)