Scope of the regulations

1  (1)  The following regulations apply to the electrical equipment of power stations and substations. They also apply to similar equipment, including generators, motors, transformers and lightning arresters, etc., when installed in factories, mercantile establishments or elsewhere; provided the equipment is in separate rooms or enclosures under control of properly qualified persons, and if the interiors of such rooms or enclosures are accessible only to such persons.

(2)  The regulations shall apply to all such installations except as modified or waived by the written permission of the Chief Inspector of Electrical Energy or his representative.

 General requirements

2  (1)  Rooms and spaces — All rooms or spaces in which electrical equipment is installed shall comply with the following requirements:

(a) they shall be as far as practicable non-combustible;

(b) they shall be used neither for the storage of material nor for manufacturing processes;

(c) they shall, if practicable, be free from all flyings, inflammable gas, and acid fumes in dangerous quantities;

(d) they shall be well ventilated;

(e) they should be dry; in outdoor stations or stations in wet tunnels or subways all live parts of equipment shall be enclosed in weather-proof cases unless the equipment is suitably designed to withstand the prevailing conditions.

(2)  Rotating machinery — This shall be installed upon suitable supports or foundations.

 Illumination

3  Rooms and spaces where electrical apparatus or machinery is located shall have means for adequate artificial illumination in accordance with good modern practice. This means of illumination shall be maintained ready for use at all times. A separate emergency source of illumination from an independent generator, storage battery, gas main, lanterns (the last two should not be used in battery-rooms), or other suitable source shall be provided in every station where an attendant is located.

 Enclosing walls and ceilings

4  (1)  Walls —Rooms and spaces shall be so arranged with fences, screens, partitions or walls as to prevent entrance of unauthorized persons or interference by them with equipment inside, and entrances not under observation of an authorized attendant shall be kept locked. Signs prohibiting entrance to unauthorized persons shall be displayed at entrances.

(2)  Ceilings — Above all equipment substantial roofs or ceilings shall be provided, except above equipment where such portions as would be injured by rains or by flying or falling objects are suitably enclosed or guarded to prevent such damage.

 Floors, floor openings, passageways, stairs

5  (1)  Floors shall have even surfaces and afford secure footing. Projecting nails, loose boards, uneven or greasy wood floors and slippery floors are prohibited.

(2)  Passageways, including stairways and working spaces, shall be unobstructed, and (except such as are used solely for infrequent inspections, construction and repair) shall provide at least 6.5 feet head-room. (See Regulation No. 12 for working space.)

(3)  All floor openings and raised platforms shall be provided with suitable railings and, where necessary, also with suitable toe-boards.

(4)  All stairways consisting of 4 or more risers shall be provided with handrails. For long and steep stairs one or more landings or turns shall be provided. Toe-boards shall, where practicable, be arranged at back of stairway treads where over exposed live or moving parts.

(5)  The heads of permanent ladders shall be provided with guards, such as gates or sliding-pipe sections, whenever the heading breaks the continuity of a railing adjacent to working space. For long ladders one or more landings, turns or safety loops shall be provided.

 Exits

6  (1)  Each room or space and each working space about equipment shall have suitable means of exit which shall be kept clear of all obstructions.

(2)  If the plan of the room or space and the character and arrangement of equipment are such that an accident would be liable to close or make inaccessible a single exit, as in the case of long narrow rooms, platforms, passageways, spaces behind switchboards, or wire and pipe tunnels, a second exit shall be provided.

 Firefighting appliances

7  Each room or space where an operator is in attendance shall be provided with adequate approved fire extinguishing appliances, conveniently located and conspicuously marked.

 Oil-filled apparatus

8  (1)  Where practicable, indoor apparatus containing oil, such as transformers, static condensers, induction regulators, lightning arresters, circuit breakers and switches, shall be isolated from other kinds of equipment and provided with oil-sills or other devices designed for the retaining or drainage of escaping oil. Whenever located on balconies or containing large quantities of oil, this shall always be done in the case of circuit breakers and switches.

(2)  Such apparatus, if in large groups or containing large total amounts of oil, shall be installed in fire-resistive enclosures, well ventilated to outside of building to prevent dangerous accumulation of oil vapours, free from apparatus likely to take fire from burning oil, subdivided to a reasonable extent, and having doors or windows so located or arranged that burning oil would not be liable to pass through to inflammable material or apparatus outside the enclosure. Where oil-filled apparatus is installed outdoors near building walls, these walls shall be of fire resistive construction and shall have doors or windows so located and arranged that burning oil is not liable to pass through them to inflammable material or apparatus.

 General requirement

9  All electrical equipment shall be of such construction and so installed and maintained as to reduce the life hazard as far as practicable.

 Inspections

10  All equipment shall receive such periodic inspection by a qualified person in charge as shall ensure it being maintained in good condition. Defective equipment shall be put in good order or permanently disconnected. Defective wiring shall be repaired or removed.

 Protective grounding

11  (1)  All exposed non-current-carrying metallic parts of electrical equipment operating at over 150 volts to ground shall, with the exceptions herein mentioned, be permanently and effectively grounded. This includes covers, cases, metallic guards and screens, conduits, handles, levers, and such metallic parts for starters, switches, circuit breakers, fuses, transformers and frames of motors, generators, switchboards, etc. This rule shall also apply to electrical equipment operating at less than 150 volts to ground, unless such equipment is effectively insulated.

(2)  Frames of direct current railway generators and rotaries and single polarity type switchboards of less than 750 volts need not be permanently grounded, provided they are effectively insulated and not in proximity to grounded surfaces to which persons might inadvertently make circuit.

(3)  Electrical equipment or conductors normally operating at more than 750 volts on or about which repairs or other work may occasionally be done, while separated from a source of electrical energy by switches or disconnectors only, shall be provided with some means such as switches, connectors or readily accessible ground conductor for grounding them, unless a thoroughly reliable procedure be adopted such as locking or tagging of switches whereby all possibility of such equipment or conductors being made alive is eliminated.

 Working space about electrical equipment

12  (1)  Adequate working space with secure footing shall be maintained about all electrical supply equipment which requires adjustment or examination during operation.

(2)  The spaces shall be so arranged as to give the authorized attendants ready access to all parts requiring attention, and shall provide the following minimum horizontal dimensions for the working spaces in front of live parts when necessarily exposed:

(a) for parts on one side of more than 300 volts and not more than 750 volts to ground and no live or grounded parts on the other side of the working space, 3 feet;

(b) for parts on one side of more than 750 volts to ground and no live or grounded parts on the other side of the working space, 3 1/2 feet;

(c) for parts on one side of more than 300 volts and not more than 750 volts to ground and live or grounded parts on the other side of the working space, 3 1/2 feet;

(d) for parts on one side of more than 750 volts to ground and live or grounded parts on the other side of the working space, 5 1/2 feet.

(3)  Concrete or masonry walls shall be considered as grounded parts.

(4)  Voltage to ground in the case of an insulated system means the voltage between conductors.

(5)  Where the working space about the electrical equipment is less than that specified above, suitable enclosures or barriers shall be provided to prevent inadvertent contact with live parts. If such enclosures must be opened or barriers removed while the parts they guard are alive, all surrounding floors shall be provided with suitable insulating platforms or mats so placed that the operator cannot touch the live parts without standing on the mat or platform, and where grounded parts are adjoining the working space, same shall be guarded by barriers or screens.

(6)  Where bus-bars, switches, fuses and other current-carrying parts of more than 750 volts are ordinarily guarded by covers or by being placed in separate rooms, adequate working space shall be provided about the live parts (unless effectively isolated by elevation as hereinafter specified), so that when they are occasionally exposed the operator will not be required to bring any part of his body within the following horizontal distances:

 Guarding live parts

13  (1)  Protection by enclosures, barriers or mats shall be provided for persons near otherwise exposed ungrounded current-carrying parts of electrical equipment operating at more than 300 volts to ground and not effectively isolated by elevation as hereinafter specified.

(2)  In addition, suitable permanent insulating guards shall be provided where necessary, so that persons cannot while touching the current-carrying parts at the same time inadvertently come in contact with other live parts or grounded parts.

(3)  Enclosures may consist of suitable casings or suitable insulating coverings. The insulating covering of conductors shall be depended upon only when it is impracticable to install more suitable guards, and then only when very substantial, thoroughly dry, and containing no non-insulating flame-proofing compound or oil-soaked rubber.

(4)  Barriers may consist of horizontal or vertical strips placed in front of current-carrying parts, or of closely spaced partitions between such parts, extending beyond the exposed sides of the current-carrying parts.

(5)  Where covers, casings or barriers must at any time be removed while the parts which they guard are alive, they shall be of insulating material or so arranged that they cannot readily be brought in contact with the live parts.

(6)  Enclosing or barrier guards not of grounded metal shall be of substantial material and spaced from the current-carrying parts not less than 3 times the needle-point sparking distance at the voltage concerned, of the intervening air, oil or other dielectric.

(7)  Mats may be of wood, held together by wood pins, or of cork matting, linoleum or rubber. The material and construction shall be suitable for the voltage concerned and for the prevailing conditions. If subject to moisture or to accumulation of conducting dust, flyings or chips, mats shall provide surfaces minimizing the hazards from these sources.

 Isolating live parts by elevation

14  Current-carrying parts need not be guarded if the following distances above floors, platforms, etc., which may be occupied by persons are maintained:

 Hazardous locations and deteriorating agencies

15  (1)  In locations where inflammable gas or inflammable flyings normally exist in dangerous quantities all parts at which sparking or arcing is liable to occur, such as rheostats and resistance devices, shall be so enclosed as to reduce the hazard as far as practicable.

(2)  This enclosure shall be by one of the following methods:

(a) by placing in separate compartments or rooms;

(b) by using non-absorptive non-combustible casings of the solidly enclosed or of explosion-proof type.

(3)  Suitable guards or enclosures shall be provided to protect exposed current-carrying parts, insulation of leads, or electrical devices or equipment where susceptible to injury by being installed directly under rotating equipment or in other locations where dripping oil, excessive moisture, steam, vapours or similar agencies exist.

 Identification

16  (1)  Equipment in general — Electrical supply equipment shall be suitably identified when necessary for safety. The identification may be by position, colour, number, name-plate, label, design or other means, but the method of identification chosen shall be uniform throughout any one system.

(2)  Identification marks shall not, if avoidable, be placed on removable covers or casings, such as instrument covers and disconnector compartment doors, where the interchanging or removal of these parts might lead to accident.

(3)  Generators and motors — Generators and motors shall be provided with name-plates giving the maker's name, the rating, normal full-load speed and the voltage.

 Speed control and stopping devices

17  (1)  Speed limits for prime movers — Prime movers driving generating equipment shall be provided with automatic speed limiting devices where harmful overspeed can otherwise occur, in addition to their governors, if necessary, as with some types of steam turbines.

(2)  Stops for rotating equipment — Stopping devices, such as switches or valves, which can be operated from locations convenient to machine operators, shall be provided for prime movers or motors driving generating equipment.

(3)  Devices which operate in such a way that the development of defects or their becoming inoperative will stop the units protected shall be used where practicable.

(4)  Controls to be used in emergency for machinery and electrical equipment shall be so located as to permit operation with a minimum of danger during such emergency.

(5)  Speed limit for motors — Machines of the following types shall be provided with speed limiting devices unless the load and the mechanical connection thereto are of such a character as to safely limit the speed, or unless the machine is always under the manual control of a qualified operator:

(a) separately excited direct current motors;

(b) series motors;

(c) motor-generators and converters which can be driven at excessive speed from the direct current end, as by a reversal of current or decrease in load.

The required limitation of speed may be obtained by the use of a relay, centrifugal switch or other similar device which will cut off the supply of energy when excessive speed is attained.

(6)  Low voltage protection — All motors so employed or arranged that an unexpected starting of the motor is a hazard, except those with an emergency use and where the opening of the circuit may cause a special hazard, such as exciter or condenser pump motors, shall be equipped with low voltage protection which will automatically open the motor circuit when the voltage falls below an operating value.

(7)  Low voltage releases — Where the speed control of direct current motors is accomplished by varying the field resistance, and the nature of the load and the range of the field rheostat are such as to make a dangerous speed attainable and no speed limit devices are used, the field rheostat shall be arranged with low voltage releases or other devices so that the motor cannot be started or continued in operation under dangerously weakened field, except where the operation of such a device might result in serious injury to service or apparatus.

 Terminal bases and bushings

18  (1)  Terminal bases when used on motors or generators shall be of suitable non-combustible, non-absorptive, insulating material, such as slate, marble or porcelain.

(2)  Bushings where used for wires coming through the frames of motors or generators shall be of porcelain, suitable composition material or of hardwood properly filled, except that soft rubber may be used if not exposed to oils, grease or other deleterious substances in such quantities as to cause their rapid destruction.

 Motors

19  (1)  Starters — Starting apparatus shall be located in sight of the motor it controls.

(2)  Motors in hazardous locations — Motors with their auxiliary equipment at which sparking or arcing or high temperature is liable to occur, when in rooms normally containing explosives, inflammable gas or inflammable flyings, shall be so installed as to reduce the hazard, by enclosure in an adequately ventilated separate compartment, by solidly enclosed or explosion-proof type of equipment, or, when protected against flyings only, by partitioning off a space or by a suitable boxing.

(3)  Motors permanently located on wooden floors shall, where necessary, be provided with suitable drip pans.

 Rotating parts

20  All rotating parts of machinery, including pulleys, flywheels, gearing, couplings, belts, chains and projecting shaft ends, shall be entirely enclosed in suitable casings, or otherwise adequately guarded by rails or barriers, so that persons are not liable to be injured by those parts.

 Location of transformers

21  Transformers shall be installed according to one of the following methods:

(a) on poles, in accordance with Overhead Line Rules, or under certain conditions on walls of buildings as herein mentioned;

(b) in outdoor enclosures such that unauthorized persons cannot readily come in contact with any part of the casings or wiring;

(c) in buildings used for other than station purposes, provided they are placed in ventilated fire-proof transformer vaults or rooms which shall be made inaccessible to unauthorized persons;

(d) in powerhouses, substations or specially constructed transformer vaults. If other equipment be therein contained, oil-sills and suitable arrangement for draining shall be provided. (See Regulation No. 8.)

 Grounding low voltage circuits

22  (1)  All transformer secondaries (including instrument transformers) shall be permanently grounded, provided the maximum voltage between the grounded point and any other point on the circuit does not exceed 150 volts.

(2)  Where secondaries of current transformers are used with indicating watt-meters the potential coils of which are connected directly to the primary circuit, such secondaries need not be grounded.

 Current-transformer secondary circuits

23  Secondary circuits of current transformers, including constant-current and instrument transformers, shall be provided with means for short-circuiting them which can be readily connected while the primary is energized, and which are so arranged as to permit the removal of any instrument or other device from such circuits without opening the circuits.

 Resistance devices

24  (1)  Rheostats shall be not less than 1 foot from combustible material or separated therefrom by a slab or panel of non-combustible, non-absorptive material not less than l/2 inch in thickness, and secured in place by bolts independently of the rheostat supports.

(2)  Rheostats or resistance devices shall not be placed where spattering molten metal due to high temperature in the rheostat may fall upon inflammable material or spaces frequently occupied by persons.

 Ground detectors

25  Every station supplying circuits which are not permanently grounded shall be provided with one or more reliable means of ground detection which can be applied for determining the existence of a ground on any such circuit extending outside the station. When lamps or volt-meters are used they shall be normally disconnected and a switch provided for taking indication or readings when desired.

 Electrical protection

26  (1)  Conductors shall be suitable for their location, use and voltage, and shall be protected against overloading by suitable automatic circuit breakers or fuses, excepting as mentioned under Regulation 36.

(2)  Conductors normally grounded for the protection of persons shall be arranged without fuses or automatic circuit breakers interrupting their continuity between the source of electrical supply and the point at which the ground conductor is attached, unless the circuit breaker opens all conductors of the circuit with one operation.

(3)  If exposed through transformer windings or outdoor circuits to higher voltages, circuits of less than 750 volts shall be isolated or adequately guarded.

 Mechanical and thermal protection

27  (1)  Where exposed to mechanical injury, suitable casing, armour or other means shall be employed to prevent injury or disturbance to conductors, their insulation or supports.

(2)  Where conductors with insulating coverings are closely grouped and any one is liable to damage from nearby conductors (as sometimes on the rear of switchboards or in cableways), they shall have a substantial flame-proof outer covering.

(3)  Large conductors liable to be torn from their supports by the forces to which they are subjected (as by the magnetic fields produced) shall be so supported that they cannot come in contact with the surfaces along which they are run if uninsulated or with other conductors and equipment. This applies in particular to generator leads and conductors liable to large short-circuit currents.

(4)  Conductors between generators and outside lines shall be accessible and supported on approved non-combustible, non-absorptive insulators, or run as approved multiple cable adapted for the voltage location and conditions obtaining or placed in metal conduit, tile or other fireproof ducts.

 Guarding conductors

28  (1)  Use of enclosing casings — Where insulated conductors are enclosed, suitable permanently grounded metal conduit or grounded metal sheathing shall be used; or in lieu thereof either ducts, runways or compartments of tile, bituminized fibre, concrete or other suitable fire-resistive materials may be used, if containing no exposed combustible material and if installed in approved manner. In damp places, conduit, ducts or runways shall be made waterproof and be provided with suitable means for draining off condensation, unless the conductors contained are lead-sheathed cables.

(2)  Conductors of more than 750 volts in conduit or sheathing — Conductors operating at more than 750 volts (unless separately supported and effectively isolated by elevation or by enclosing in suitable compartments or screens) shall be suitable metal-sheathed cable, run in metal conduits or suitable fire-resistive ducts or compartments, with the metal sheathing permanently grounded. Other covering may be used in suitable grounded metal conduit or insulating duct when installed in dry locations. The conduit or duct shall provide a smooth runway, with smooth outlets. Metal conduit, if used, shall be made electrically and mechanically continuous with the metal casings of all conduit fittings. If not exposed to moisture, a metal sheath need not be continuous over splices, provided that the sheaths are suitably bonded together electrically around the splice by a conductor having current capacity not less than No. 6 copper.

(3)  Metal-sheathed cable outlets of more than 750 volts — The insulation of the several conductors of multiple-conductor cable, where leaving the metal sheath at outlets, shall be thoroughly protected from mechanical injury, moisture and electrical strains by means of a pot-head or equivalent method.

(4)  Open Conductors of More than 750 Volts — When any open insulated conductors of more than 750 volts, or any open bare conductor of more than 300 volts to ground, are necessarily brought closer to the floor-line than the clearances required for isolation by elevation, they shall be guarded by permanent screens, by enclosing partitions or by suitable barrier-guards. Where barrier-rails only are used, the surrounding floors shall be provided with suitable insulating platforms, mats or covers.

(5)  When even at less than 300 volts to ground, bare conductors shall be guarded if not isolated by elevation, wherever liable to be short-circuited or grounded by conducting tools or other objects.

 Guarding hazardous locations

29  (1)  Conductors in locations where inflammable gas normally exists shall be in metal conduit or metal-sheathed cable. All fittings and outlets of such conduit and cable shall be electrically and mechanically continuous with the conduit or metal sheath, and the conduit shall be sealed to prevent entrance of gases.

(2)  This rule does not apply to conductors of large cross-section which obviously cannot be placed in conduit, such as copper bars connecting large cells with end-cell switches.

(3)  Conductors in damp locations, if neither in conduit nor in waterproof metal sheaths in other suitable ducts, shall be effectively isolated and supported on a suitable type of insulator.

 Lighting fixtures

30  (1)  Arrangements of permanent fixtures and plug receptacles shall be such that portable cords need not be brought into dangerous proximity to live or moving apparatus. All lamps shall be arranged to be controlled or replaced from safely accessible places.

(2)  Pendant conductors shall not be installed where they can be readily moved so as to bring them in contact with live parts of electrical equipment.

(3)  Portable conductors shall be attached to fixed wiring only through separable attachment plugs which will disconnect all poles by one operation.

 Wiring for illumination

31  Wiring for the illumination of stations shall be installed and protected in standard and regular manner.

 Circuit breakers and switches

32  (1)  On circuits of more than 7 500 volts, circuit breakers and switches shall be operated normally by remote control, either electrical or manual.

(2)  On circuits of over 750 volts and less than 7 500 volts, they shall be operated by remote control, either electrical or manual, or by direct control, when provided with enclosing casings protecting the operator from danger of contact with current-carrying parts.

(3)  On circuits of less than 750 volts, if not protected as above, they shall have insulating handles, guards, disks or shields, so arranged as to make it unlikely that the hand will come in contact with live parts or be burned by arcing.

(4)  Oil circuit breakers and oil switches shall, wherever practicable, be isolated from other types of switches and other electrical apparatus and shall conform to Regulation No. 8.

 Disconnectors

33  (1)  Unless a circuit breaker or switch operating on a circuit of over 750 volts makes an air-break, there shall be installed between it and the source of energy supply a suitable air-break disconnector, or equivalent device having an air-gap suitable for the operating voltage of the circuit.

(2)  An air-break disconnector shall be inserted in each conductor between electrical equipment or lines, and sources of supply of more than 750 volts, if the equipment or lines may be worked on while the sources may be alive.

(3)  Air-break disconnectors shall be provided for the isolation of station equipment from outside lines of more than 750 volts where such lines may be alive from another source of supply or from contact with other lines.

(4)  The switch-blades shall be "dead" when the switches are open. Exception will be made in the case of switches which may have to transmit supply in either direction and in certain cases for double-throw switches.

(5)  Switch-blades shall maintain such alignment under service conditions that they can be closed with a single unhesitating motion. The minimum size of blade for any disconnecting switch shall be 1" x 5/32".

(6)  Safety catches shall be provided on disconnecting switches when mounted in such a way that gravity tends to open them, and also when the magnetic forces due to short circuits are of values liable to open them.

 Accidental closing

34  (1)  All types of switches shall be so installed as to minimize the danger of accidental operation, and, where practicable, so that gravity cannot close them. Such switches as may tend to close by gravity shall be provided with a proper latch or stop-block to prevent accidental closing.

(2)  Circuit breakers, switches and disconnectors shall be so arranged that they can be secured or blocked in the open position, or plainly tagged to prevent careless closing while work is being done on equipment controlled by them.

(3)  Locking is recommended rather than blocking wherever parts of equipment are remote from the point of control.

 Where switches are required

35  Suitable switches or circuit breakers which may be manually operated shall be inserted in all leads (except a grounded conductor) to generators, motors, transformers (except instrument transformers), and all outgoing supply circuits, except as listed below:

(a) in most cases the switch called for should be capable of opening the circuit under overloads; in some cases, as between generators and transformer banks used with them, disconnectors only may be required;

(b) where 2 or more pieces of electrical supply equipment or supply lines are operated as a single unit, no switch is necessarily required between them;

(c) when switches in transformer vaults are unnecessary for operating requirements, permission for their omission may be given;

(d) in certain cases permission may be given for omission of switches from generator field-leads, and for some classes of generators single-pole switches may be used.

 Where automatic circuit breakers or fuses are required

36  (1)  All circuit leads to motors, constant-potential generators, transformer primaries (except series transformers), and station auxiliaries, and all outgoing circuits, shall, except as provided in (2) and (3) below, be protected from excessive current by suitable fuses or automatic circuit breakers or approved type fuses.

(2)  A motor-driven generator or a rotary converter, if adequately protected from excessive load by fuses or automatic circuit breakers in the motor leads or the primary supply leads, may not require such devices in the generator or secondary leads.

(3)  No fuses or circuit breakers are required in the following cases:

(a) grounded conductors;

(b) field-excitation circuits;

(c) leads of alternating current generators;

(d) leads connecting 2 or more pieces of electrical supply equipment operated as a single unit;

(e) circuits supplying interconnected three-wire systems of direct current distribution;

(f) circuits the opening of which may cause greater hazard to life or property through interruption of service.

 Fuse protection

37  (1)  All fuses, except those in two-wire circuits operating at not more than 150 volts between conductors and carrying not more than 30 amperes, shall be made "dead" before handling; and shall always be made "dead" before handling, regardless of voltage and current, in locations where a person may have to stand on grounded surfaces when re-fusing. This rule requires an individual switch ahead of every fusible cut-out as specified for the purpose of disconnecting the fuses of each circuit from all sources of supply.

(2)  Combined disconnectors and fuses and protected type fuses up to 2 500 volts, which can be handled without subjecting the hand of the operator to proximity to unprotected live parts, and with which danger of grounding to metal case in the process of operating is adequately eliminated, need not have separate air-break switches ahead of them.

 Arcing or suddenly moving parts

38  (1)  Fuses and circuit breakers shall, as far as possible, be so located and shielded that persons will not be burned by their operation.

(2)  Parts of equipment which move suddenly in such a way that persons in the vicinity are liable to be injured by being struck by them, such as handles, levers or other parts of circuit breakers, shall be guarded or isolated.

 Accessibility and indicating arrangements

39  (1)  All circuit breakers, switches, fuses, starting rheostats and other control devices shall be readily and safely accessible to authorized persons unless remotely controlled. They shall be so arranged or marked as to identify the equipment controlled by them, and, with the exception of fuses, shall indicate whether they are open or closed.

(2)  The control devices for switches shall indicate whether switches are open or closed. Lever-operated circuit breaker type switches shall be equipped with indicating device to show whether they are open or closed whenever the position of the handles does not clearly do so.

 Location and accessibility

40  (1)  Switchboards shall be so placed that the operator will not be endangered by any live or moving parts of machinery or equipment located near the board or by any accident which might happen to such live or moving parts.

(2)  They shall be so placed as to reduce to a minimum the danger of communicating fire to adjacent combustible material.

(3)  Banks of remote-controlled circuit breakers and switches shall be adequately separated and guarded and shall, together with their respective disconnectors, be legibly numbered for ready identification.

(4)  The space at the back of the board shall be kept clear of rubbish and shall not be used for storage.

(5)  Switchboards shall be accessible to authorized operators from both sides when the connections are on the back, but may be placed against a wall when operating at not more than 750 volts with the wiring entirely on the face.

(6)  Switchboards shall have all switches so arranged that the points of control are readily accessible to the operator. Instruments, relays and other devices requiring reading or adjustment shall be so placed that work can be readily performed from the working space.

 Material and illumination

41  (1)  Switchboards shall be made of non-combustible material and be kept free from moisture.

(2)  Sufficient illumination shall be provided both for the front and rear of the switchboard, so that the switchboard may be readily operated and instruments conveniently read.

 Necessary equipment

42  Switchboards which control generating equipment or outgoing supply circuits shall (except in substations without regular attendance) be equipped with such instruments as are necessary to show operating conditions.

 Arrangement and identification

43  (1)  Where cables leading from a switchboard are placed in conduits, the latter shall be so arranged that there is the minimum amount of open wiring.

(2)  Standard spacings and clearances shall be given at all open switches and fuses.

(3)  Connections, wiring and equipment of switchboards and panel boards shall be arranged in an orderly manner, and all switches, fuses and circuit breakers shall be plainly marked, labelled or arranged so as to afford ready means for identifying circuits or equipment supplied through them, in accordance with Regulation 16.

(4)  Switchboards shall have the number of bare parts at different potentials on any panel reduced to a minimum and these parts shall be effectively separated.

 Guarding live parts on switchboards

44  (1)  All switchboards operating at more than 300 volts to ground and located near passageways shall be guarded from these by suitable enclosures or barriers, and shall (unless under constant attendance during operation) be made inaccessible to other than authorized persons.

(2)  For the protection of the operator, where parts of more than 300 volts to ground are not otherwise guarded or isolated by elevation, suitable insulating floors, mats or platforms providing good footing shall be so placed that the operator cannot readily touch the live parts unless standing on such floors, mats or platforms.

(3)  No switchboard shall have exposed on its face within 6 feet from floor-line any current-carrying part of more than 750 volts, except as noted in paragraph (5) below, and excepting direct current railway boards not exceeding 1 500 volts, which, where exceeding the nominal 750 volts, shall be so constructed that the operator cannot inadvertently touch parts of more than 750 volts. Dead-face panels and remote control are recommended as means for accomplishing this result where isolation by elevation is impracticable or undesirable.

(4)  When working space adjacent to live parts cannot be provided in accordance with above rule, suitable guards shall be arranged to protect the operator from accidental contact with parts of more than 300 volts. Suitable insulating guardrails, sufficiently spaced from the face or back of the board, or suitable guards perpendicular to the face or the back of the board, and extending out beyond the live parts, shall be used where practicable.

(5)  Plug-type switchboards shall, except while connections are being changed, have no current-carrying part exposed on face of boards, and if practicable they and their plug connectors shall be so arranged where the operating voltage exceeds 150 as to have all current-carrying parts guarded so long as they are alive, even while connections are being changed.

(6)  No switchboard shall have current-carrying parts of more than 7 500 volts exposed (unguarded), unless these parts are effectively isolated by elevation, except at times when occasionally left exposed by removal of covers or entrance into enclosures, such as switch and instrument-transformer cells or compartments, which are ordinarily unoccupied by persons. For such parts, if exposed while alive for any purpose (including buses and disconnectors in compartments), working space shall be provided complying with the requirements stated under Regulation 12.

 Location

45  (1)  Lightning arresters shall be attached to all ungrounded sides of each system of more than 7 500 volts connected to overhead circuits, except circuits in cables with grounded metal sheath.

(2)  This rule need not be complied with in locations where thunderstorms are infrequent at all seasons of the year.

(3)  Lightning arresters with auxiliaries, when installed inside of buildings, shall be located well away from all other equipment, passageways and combustible parts of buildings.

 Provisions for disconnecting

46  (1)  Lightning arresters on circuits of more than 2 000 volts shall be so arranged, isolated and equipped that they may be readily disconnected from the line by air-break manual disconnectors, having air-gaps of not less than 4 times the equivalent needle-point sparking distance in air of the operating voltage of the circuit to which the arresters are connected, and never less than 7 inches.

(2)  Lightning arresters, unless provided with disconnectors which are always opened before work is done on the arresters, shall be so arranged that necessary adjustments are possible (without approach to current-carrying parts) through the use of permanently grounded mechanisms or suitable insulating appliances. Where charging or adjusting must be done with arresters alive, permanently grounded mechanisms or suitable insulating appliances shall always be provided.

(3)  All choke-coils, gap-electrodes or other attachments inherent to the lightning protective equipment shall have an insulation from the ground, or other conductors equal at least to the insulation demanded at other points of the circuit in the station.

 Connections and groundings

47  (1)  Line connections and ground leads shall be run as directly as possible, and be of low impedance and ample current capacity.

(2)  Kinks, coils and sharp bends in the wires between the arresters and the outdoor lines shall be avoided.

(3)  Lightning arrester ground connections shall not be made to the same artificial ground as circuits or equipment but shall be spaced at least 20 feet therefrom. The combined resistance of the ground wires and ground connection shall not be less than 25 ohms. In the case of driven-pipe grounds, at least 2 pipes not less than 7 feet apart shall be used.

 Transmission-line telephone protection

48  All telephone equipment which is connected to telephone lines which are carried on the same poles as power wires of over 5 000 volts, or which parallel power lines in such a manner that under normal conditions more than 150 volts are induced between the terminals of the telephone equipment and ground, shall be provided with adequate telephone protective equipment to obviate the possibility of accident from high voltage on the telephone lines.