1 Electrical Systems Final

7/28/2019 1 Electrical Systems Final

1/51

7/14/20

ELECTRICAL SYSTEMS

1.1 DEFINITION OF ELECTRICITY

a form of energy generated byfriction, induction or chemicalchange, having magnetic, chemicaland radiant effect.

the motion of free electrons througha solid conductor.

1.2 SOURCES OF ELECTRICITY

STORAGE BATTERIES

GENERATORS

1. GENERAL


2/51

7/14/20

STORAGE BATTERIES

are used to supply emergencylighting circuits for hallways,

stairways, exits and to energizepolice and fire alarm systemsand certain types of signalsystems.

GENERATORS

for generating electric current

Alternating Current Generators orAlternators The bulk of electrical energyutilized today is in the form of alternatingcurrent, including energy for power and

lighting.

Direct Current Generators Thesefurnish electrical energy for elevators,escalators, intercommunicating telephonesystems, control of signal systems, andclock systems.


3/51

7/14/20

1.3 OTHER DYNAMO ELECTRICMACHINES

MOTORSfor convertingelectrical energy to mechanicalenergy.

TRANSFORMERSforconverting one voltage to

another, from lower to higheror from higher to lower

ROTARY CONVERTERSfor changing alternatingcurrent to direct current andvice versa.

1.4 TYPES OF CURRENT

ALTERNATING CURRENT acurrent which is periodicallyvarying in time rate and indirection. It rises from zero tomaximum, falls to zero, reversesits direction and again returns tozero.

DIRECT CURRENT a currentwhich flows at a constant time rateand in the same direction.


4/51

7/14/20

UNIT OF QUANTITY

1.5 UNITS OF ELECTRICITY

COULOMB a coulomb of electricitycomprises approximately 6.25 x 10 18electrons.

AMPERE An ampere of currentrepresents a rate of flow of onecoulomb or 6.25 x 10 18electrons/second through a givencross section.

UNIT OF ELECTRIC POTENTIAL

VOLT is the electromotive forceor potential difference between twopoints in an electric field which willmove a charge of one coulombbetween these points.

UNIT OF RESISTANCE

OHM The resistance which willallow one ampere of current to flowwhen one volt is impressed upon it.

UNIT OF ELECTRIC POWER

WATT the unit of electricpower or the rate of doingelectrical work.

UNIT OF ENERGY

WATT-HOURS the unit ofenergy or the capacity for doingwork.


5/51

7/14/20

1.6 OHMS LAW

I (amp) = V(Volts) /R(Ohms)

The current, I, that will flow in ad-c circuit is directly proportional tothe voltage ,V, and inverselyproportional to the resistance , R,of the circuit.

is the effective utilization of availableenergy by reducing peak loads andlowering demand charge. The controldevices and systems are referred to asload shedding control, peak demandcontrol, peak load regulation, and poweruse control.

LOAD SCHEDULING AND DUTY-CYCLE CONTROL the installationselectric loads are analyzed and scheduledto restrict demand by shifting large loads

to off-peak hours and controlled to avoidcoincident operation.

DEMAND METERING ALARM inconjunction with a duty cycle controller,demand is continuously metered and analarm is set on when a predetermineddemand level is exceeded.

1.7 ELECTRIC LOAD CONTROL


6/51

7/14/20

AUTOMATIC INSTANTANEOUSDEMAND CONTROL also called ratecontrol, it is an automated version of thedemand metering alarm system, where it

automatically disconnects or reconnects loadsas required.

IDEALCURVE CONTROL This controlleroperates by comparing the actual rate ofenergy usage to the ideal rate, and controlsKW demand by controlling the total energyused within a metering interval.

FORECASTING SYSTEMS arecomputerized systems which continuouslyforecast the amount of energy remaining inthe demand interval, then examine the statusand priority of each of the connected loadsand decide on the proper course of action.

WATTMETER

VOLTAGELEADS

LOAD

WM

CURRENTLEADS

POWERSOURCE

1.8 MEASURING ELECTRIC CONSUMPTION

KWH METERS Tomeasure energy, thefactor of time isintroduced, such that;energy = power xtime. A-C electricmeters are basicallysmall motors, whose

speed is proportionalto the power beingused. The number ofrotations is counted onthe dials which arecalibrated directly inkilowatt-hours.


7/51

7/14/20

2. BUILDING ELECTRICAL SYSTEMS

2.1 BRANCH CIRCUITS

An electrical circuit may be defined as a

complete conducting path carrying currentfrom a source of electricity to and throughsome electrical device or load and back to thesource. The two wire circuit, which is themost elementary of all wiring systems,consists of a live wire carrying the current tothe various power consuming devices in thecircuit and a neutral or grounded wire whichis the return wire carrying the circuit back tothe source of supply.

SERIES CIRCUIT

PARALLEL CIRCUIT

SERIES CIRCUITis one in which thecomponents are connected in tandem. Allseparate loads of the circuit carry thesame equal current and the totalresistance, R, is the sum of theresistances around the circuit.

PARALLEL CIRCUIT (or MultipleCircuit) is one in which the

components or loads are so arrangedthat the current divides between them.Each outlet has a live wire connected tothe current carrying wire of the circuitand also a neutral wire or grounded wireconnected to the return wire of thecircuit. With this system, the total currentflowing through the circuit is the sum ofthe current flowing through each outlet.

R = R1 + R2 + R3 + R4 + R5

10 ampR 1 R 2

10 amp

ELECSOURCE

CIRCUIT IN SERIES

R 5 R 410 amp

10 amp

R 3

ELECTRICALSOURCE

CIRCUIT IN PARALLEL

3 amp

1 amp1 amp1 amp+

R 1 R 2 R 3

1R =

1/R1 + 1/R2 + 1/R3


8/51

7/14/20

CLASSIFICATIONS OF BRANCH CIRCUITS

General Purpose Branch Circuit -supplies outlets for lighting and

appliances, including conveniencereceptacles.

Appliance Branch Circuit - suppliesoutlets intended for feeding appliances.Fixed lighting is not supplied.

Individual Branch Circuit - isdesigned to supply a single specific item,such as a motor load or a unit air-conditioner.

SIZE REQUIREDFOR ITEM FED

15, 20, 30,or 50A A A

LTG AGENERALLY

15, 20A

SINGLE ITEM

Branch Circuit

The portion of an electricalsystem extending from the final

overcurrent device protecting a

circuit to the outlets served by

the circuit

Distribution PanelA panel for distributing

power to other panels or to

motors and other heavy

power-consuming loads.

Controls, distributes and

protects a number of similar

branch circuits in an

electrical system

Low-Voltage

Of or pertaining to a circuit in which alternating

current below 50 volts is supplied by a step-down

transformer form the normal line voltage used in

residential systems to control doorbells,

intercoms, heating and cooling systems and

remote lighting fixtures. Low-voltage circuits do

not require a protective raceway

General Purpose Circuit

A branch circuit that supplies

current in a number of outlets for

lighting and appliances

Appliance Circuit


current in one or more outlets

specifically intended for

appliances

Individual Circuit


current only to a single piece of

electrical equipment


9/51

7/14/20

GENERAL CIRCUITING GUIDELINES

1. General: Branch circuits shall besufficient to supply a load of 30watts per square meter (3 watts persquare foot) in buildings excludingporches, garages and basements.

2. In all but the smallest installations,connect lighting, conveniencereceptacles, and appliances inseparate circuits. The Code requires aminimum of 2 - 20 amperesappliance branch circuit to feed allsmall appliance outlets in the kitchen,pantry, dining and family room.

DINE

KIT

Ref

C2

Range

C1C4

C3

C3

C320 amp

20

amp

3. Convenience receptacles in an areashall be wired to at least twodifferent circuits so that in case offailure in any one of the circuits, theentire area will not be deprived ofpower.

4. General purpose branch circuits shallbe rated at 20 amperes wired withNo. 12 AWG minimum. Switch legs

may be No. 14 AWG if the lightingload permits.

5. Limit the circuit load for lighting andsmall appliances on 15 amp and 20amp circuit loads and on 15 and 20amp overcurrent devices respectively.


10/51

7/14/20

1

2.2 SINGLE PHASE ELECTRICAL SYSTEMS

Two-Wire Single Phase DC or AC

Three-Wire Single Phase DC(EDISON SYSTEM)

Three-Wire Single Phase AC

For homes and small commercial buildings

SWITCH FUSE

220 V

110 V

110 V

A single phase electrical system caneither be 2-wire or 3-wire andcomposes two hot legs and a neutralwire.

2.2 THREE PHASE ELECTRICAL SYSTEMS

Three-Wire Three Phase AC

Four-Wire Three-Phase AC

For industries and large commercial buildings

A-B 220V

B-C 220V

A-C 220V

A B C

A

B

C

220V

N B CA

220V

220V

110V

110V

110V

MOTOR

The Three Phase AC electricity is a TripleCircuit. The lighting and outlet loads areconnected between any phase leg and aneutral line. While machineries and otherbigger loads are connected to the phase legonly.


11/51

7/14/20

1

2.3 COMPONENTS OF THE BUILDING ELECTRICAL SYSTEM

Substation

An auxiliary power station

where electrical current is

converted or where voltage

is stepped up or down

Service

The supplying of utilities required

or demanded by the public

Line Drop

The decrease in voltage between

two points on a power line,

usually caused by resistance or

leakage along the line

Service Entrance Conductor

The portion of a service conductor extending

from a service drop or service lateral to the

service equipment of a building

Watt-Hour Meter

A meter for measuring and recording the

quantity of electric power consumed with

respect to time

Transformer Vault

A fire-rated room housing

a transformer and

auxiliary equipment for a

large building

Switchgear Room

Contains the service

equipment for a large

building

Service Equipment

Equipment necessary for

controlling, metering and

protecting the electric

power supply to a builidngStandby Generator

For providing emergency power

during a power outage.

Uninterruptible Power Supply

An emergency system designed

to provide pwer automatically and

instantaneously

Switchboard

One or a group of panels on

which are mounted switches,

overcurrent devices,

metering instruments and

buses

Unit Substation

A freestanding enclosure

housing a disconnect

switch, a step-down

transformer and

switchgear

Feeder

Any of the conductors

extending from the

service equipment to

various distribution

points in a building

Service Drop

The overhead portion of service

conductors extending from the

nearest utility pole to a building

Service Lateral

The underground portion of service

conductors extending from a main

power line or transformer to a

building


12/51

7/14/20

1

Lightning Rod

Any of several conducting rods installed at the

top of a structure and grounded to divert

lightning away from the structure. Also called air

terminal

Lightning Arrester

A device for protecting electric equipment from

damage by lightning or other high-voltage

currents, using spark gaps to carry the current

to the ground without passing through the

device

Spark Gap

A space between two terminals or electrodes

across which a discharge of electricity may pass

at a prescribed voltage

Servcie Drop

The overhead portion of service conductors extending

from the nearest utility pole to a building

Servcie Lateral

The underground portion of servi ce conductors extending

from a main power line or transformer to a building

Service Conductors extend from a main power

line or transformer to the serv ice equipment of a

building

Servcie Entrance Conductor

The portion of a service conductor extending from a servi ce

drop or service lateral to the service equipment of a building

Watt-Hour Meter

Measures and records the quantity of electric power

consumed with respect to time. Supplied by the public utility,

it is always placed ahead of the main disconnect switch so

that it cannot be disconnected

For multiple-occupancy buildings, banks of meters are

installed so that each unit can be metered

independently

Grounding Rod or ElectrodeIs firm ly embedded in the earth to establish a ground

connection

To panelboards

Direct burial cable may be used for

residential service connections

A transformer is used by medium-sized and large buildings to step

down from a high supply voltage to the service voltage. To

reduce costs, maintenance and noise and heat problems, a

transformer may be placed on an outdoor pad. If located within a

building, oil-filled transformers require a well-ventilated, fire-rated

vault with two exits and located on an exterior wall adjacent to the

switchgear room. Dry-type transformers used in small- and

medium-sized buildings may be replaced together with a

disconnect switch and switchgear in a unit substation

The service switch is the main

disconnect for the entire electrical

system of a buil ding, except for any

emergency power systems.

The service equipment includes a main

disconnect switch and secondary

switches, fuses and circuit breakers for

controlling and protecting the electric

power supply to a building. It is located

in a switchgear room near the entrance

of the service conductors

The main switchboard is a panel on

which are mounted switches,

overcurrent devices, metering

instruments and busbars for controlling,

distributing and protecting a number of

electric circuits


13/51

7/14/20

1

SERVICE ENTRANCEthe point ofdelivery of electricity to a building by apublic utility company.

MAIN SWITCHBOARD The serviceentrance conductors in the form of busbars terminates in the main switchboardand connects to the distribution panel

boards by means of feeder circuitsprotected by circuit breakers. The mainswitchboard serves for the control,protection and metering of the mainfeeders.

FEEDER CIRCUITSA feeder circuitis a set of conductors which extendsfrom the main switchboard to adistributing center (panel board) with noother circuits connected to it betweenthe source and the distributing center.

SUB-FEEDER CIRCUITS are line

extensions of a feeder, fed through apanel board or cut-out, or from onedistributing center to another and havingno other circuit connected to it betweenthe two distributing centers. A sub-feederserves to distribute power from the mainfeeders to smaller local panel boards,called sub-panel boards.


14/51

7/14/20

1

PANEL BOARDS AND SUB-PANELBOARDS (also called CUT-OUTS) Theseserve to control and protect the subfeeders and branch circuits.

UTILIZATION EQUIPMENT These

are the lighting, power and motor loadsand wiring devices which are directlyhandled and utilized by users.

BRANCH CIRCUITS These aresmall capacity conductors which deliver

energy to lamps, motors and other loadswithin the circuit.

Service Switch

The main disconnect for the entire

electrical system of a building

except for any emergency power

systems

Panel

A board on which are mounted

the switches, fuses and circuit

breakers for controlling and

protecting a number of similar

branch circuits installed in a

cabinet and accessible from

the front only. Also called a

panelboard.

Bus

A heavy conductor, usually in the form of asolid copper bar, used for collecting, carrying

and distributing large electric currents. Also

called a busbar

Grounded Conductor

Any conductor of an electrical system

intentionally connected to a ground

connection

Grounding Electrode

A conductor, as a metal ground rod,

ground plate or cold-water pipe, firmly

embedded in the earth to establish a

gorund connection

Fuse

A device containing a strip or

wire of fusible metal that meltsunder the heat produced by

excess current thereby

interrupting the circuit

Circuit Breaker

A switch that automatically interrupts an electric

circuit to prevent excess current from damaging

apparatus in the circuit or from causing a fire. A

circuit breaker may be reclosed and reused withoutreplacement of any components. Also called a

breaker.

Ground Wire

A conductor connecting

electric equipment or a

circuit to a ground

connection. Also called a

grounding conductor


15/51

7/14/20

1

2.4 ILLUSTRATING THE COMPONENTS OF THE BUILDINGELECTRICAL SYSTEM

BLOCK DIAGRAMA horizontal single linediagram of the buildingselectrical system from theincoming service to theutilization items at the endof the system where themajor electricalcomponents are shown asblocks or rectangles.

RISERDIAGRAMIs a vertical linediagram of themajor electricalcomponents ofthe buildingselectrical system

presentedshowing thespatial relationsbetweencomponents.

ELEVATORS

PPMR

MACHINEROOM

5A

LP

4A

3A

2A

1A LP

LOBBY

1B

2B

3B

4B

5B

LEFTRISER

5C

4C

3C

2C

1C

ROOF

CENTRAL RISER SHAFT

RIGHT RISER

M.C.C.

MACHINE ROOM

FA

LPSE

FIRE ALARMPANELSTAIR AND EXITPANEL

M METERING

SPARE


16/51

7/14/20

1

2.5 EMERGENCY ELECTRIC SUPPLYSYSTEM

Emergency Systems provide electricpower and illumination essentially for lifesafety and protection of property duringan emergency, such as, electricity for exitlighting, elevators, fire alarm systems,fire pumps and the like.

Standby Systems provide power toselected loads not directly involved with

life safety, such as, water and sewagetreatment plants and industrial machinesfor manufacturing processes.

EMERGENCY POWER EQUIPMENT

Battery Equipment Central storagebatteries are mounted in individual racksand always provided with automaticcharging equipment.

Engine-Generator Sets are machinesintended to produce electricity andcomposed of three components: themachine and its housing (if any), fuelstorage tank and the exhaust facilities.


17/51

7/14/20

1

EMERGENCY WIRING SYSTEMSUSING THE BATTERY

Small emergency appliance connecteddirect to a storage battery

Groups of emergency loadsconnected to central storage batterythrough automatic device

Emergency equipment loads are

entirely separate from normal loadsand are generally de-energized. Thecontactor is activated when it sensespower loss.

EMERGENCY WIRING SYSTEMSUSING THE GENERATOR

Emergency system handled by asingle transfer switch whichautomatically turns on when it sensespower loss at its downstream location.

Emergency system handled bymultiple switches

Emergency service totally separatedfrom normal through its own emergencyservice entrance, coming from differenttransformers or feeders.

Same as above, but both serviceentrances supply normal loads andeach act as standby for each other.


18/51

7/14/20

1

are materials which allow the free

flow of electrons through them.

Wires are single insulatedconductors No. 8 AWG (American WireGauge or smaller; for the EnglishSystem, it is the B & S Gauge orBrowne and Sharpe Gauge. Thesmallest size of wire permitted is No.14.

Cables are single insulatedconductors No. 6 AWG or larger; orthey may be several conductors of

any size assembled into a single unit.

Bus Bars large conductors whichare not circular in cross section andusually found only to supply the mainswitch boards.

3. ELECTRICAL MATERIALS AND EQUIPMENT

3.1 CONDUCTORS

CONDUCTOR SIZES AWG/MCM STANDARD

All conductor sizes from No. 16 toNo. 0000 (also designated 4/0) areexpressed in AWG.Beyond AWG No. 4/0, a differentdesignation, MCM (or thousand circular mil)is used. In this designation, the smallestMCM size is 250 MCM or and thebiggest is 500 MCM.

A circular MIL is an artificial areameasurement, representing the square ofthe cable diameter (diam2) when thediameter is expressed in mils (thousands ofan inch). Thus a solid conductor inch indiameter is 500 mils in diameter, or250,000 circular mils in area, (500)2 or250 MCM; thus;CM/1000 = diam2 = (500)2/1000 =250,000/1000 = 250 MCMIn the metric system, conductor sizes aregiven simply as the diameter in millimeters(mm).


19/51

7/14/20

1

CONDUCTOR AMPACITY

Conductor current carrying capacity orampacity is the maximum operatingtemperature that its insulation can standcontinuously. Heat is generated as aresult of the current flowing and theconductor resistance. When conductorsare placed in an enclosed conduit, theheat generated is not as easilydissipated as it would be if the conductorwere free in the air. Thus, the currentrating of a conductor in free air is muchhigher than that for the same were it ina conduit.

TYPES OF CABLES

Armored Cable (Type AC) a fabricatedassembly of insulated conductorsenclosed in flexible metal sheath.

Metal Clad Cable (Type MC) a factoryassembled cable of one or moreconductors each individually insulatedand enclosed in a metallic sheath ofinterlocking tape of a smooth orcorrugated tube.

Mineral Insulated Cable (Type MI) afactory assembled conductor/s insulated

with a highly compressed refractorymineral insulation enclosed in a liquid andgas tight continuous copper sheath.

Non-Metallic Sheathed Cable (Type NMor NMC) also known by the tradename ROMEX, is a factory assembly oftwo or more insulated conductors havinga moisture resistant, flame retardant,and non-metallic material outer sheath.


20/51

7/14/20

2

Shielded Non-Metallic Sheathed Cable(Type SNM) a factory assembly of twoor more insulated conductors in anextruded core of moisture resistant and

flame retardant material covered withinan overlapping spiral metal tape.

Underground Feeder and Branch CircuitCable (Type UF) a moisture resistantcable used for underground connectionsincluding direct burial in the ground asfeeder or branch circuit.Service Entrance Cable (Type SE orUSE) a single or multi-conductorassembly provided with or without anoverall covering primarily used for servicewire.

Power and Control Tray Cable (Type TC) afactory assembled two or more insulatedconductors with or without associated bareor covered grounding under a metallic sheathand is used for installation in cable trays,raceways, or where supported by wire.

Flat Cable Assemblies (Type FC) anassembly of parallel conductors formedintegrally with an insulating material webdesigned specially for field installation insquare structural channels.

Flat Conductor Cable (Type FCC) consists of three or more flat copperconductors placed edge to edgeseparated and enclosed within ainsulating assembly. This type of cable

is used for appliance or individualbranch circuits installed inside floorsurfaces.

Medium Voltage Cable (MV) asingle or multi-conductor solid dielectricinsulated cable rated at 2,000 to35,000 volts. Trade name is Medium

Voltage Solid Dielectric.


21/51

7/14/20

2

3.2 INSULATORS

INSULATORS are materials whichprevent the flow of electrons through

them.

General Wiring

Trade name Type

Letter

Maximum

Operating

Temperatur

e

ApplicationProvisions

Moisture-& heat-resistantrubber

RHW 75O C167O F Dry and wetLocations

Thermoplastic T 60O C140O F Dry locations

Moisture-resistant

thermoplastic

TW 60O C140O F Dry and wetLocations

Heat-resistant

thermoplastic

THHN 90O C194O F

Dry locations

Moisture-& heat-resistantthermoplastic

THW 75O C167O F Dry and wetLocations

Moisture-& heat-resistantthermoplastic

THWN 75O C167O F Dry and wetLocations

Moisture-& heat resistantcross-linkedthermosettingpolyethelene

XHHW 90O C194O F75O C167O C

Dry locationsWet

locations

Silicone-asbestos SA 90O C194O F Dry locations

Asbestos and VarnishedCambric

AVA 110O C230O F Dry locationsonly

TYPES OF INSULATORS


22/51

7/14/20

2

CONDUITS are circular raceways usedto enclose wires and cables and are of

metal or plastic (PVC).

3.3 CONDUITS

To protect the enclosed conductorsfrom mechanical injury and chemicaldamage.

To protect people from shock hazardsby providing a grounded enclosure.

To provide a system ground path.

To protect the surroundings against firehazard as a result of overheating or shortcircuiting of the enclosed conductors.

To support the conductors.

TYPES OF STEEL CONDUITS

Heavy-wall steel conduits called RigidSteel Conduits or RSC with anapproximate thickness of 0.117 mm.

Intermediate Metal Conduit or IMC withthickness of 0.071 mm.

Thin-wall steel conduits named ElectricMetal Tubing or EMT.

RSCs and IMCs use the same fitting, called

condulets, and are threaded alike at thejoints. EMTs are not threaded but use setscrew and pressure fitting and are notrecommended for embedding in concretenor permitted in hazardous areas. IMCsyield a larger inside diameter (ID) foreasier wire pulling and is lighter than theRSC.Standard length of steel conduits is 3 M or10 ft.


23/51

7/14/20

2

3.4 RACEWAYS are channels orwiring accessories so designed forholding wires, cables and bus bars thatare either made of metal, plastic, or any

insulating medium.

3.5 OUTLETS and RECEPTACLESAn outlet is a point in the wiring systemat which current is taken to supplyutilization equipment. It refers only tothe box. A receptacle is the wiringdevice in which the utilizationequipment (appliance) cord is pluggedinto.

Convenience Outlet or AttachmentCap - the complete set-up whichestablishes connection between theconductor of the flexible cord and theconductors connected permanently tothe receptacle.


24/51

7/14/20

2

Lighting Outlet is an outlet intendedfor direct connection to a lamp holder,lighting fixture, or pendant cordterminating in a lamp holder.

Receptacle Outlet is an outlet whereone or more receptacles are installed.

3.6 SWITCHES are devices for making,breaking, or changing conditions in anelectrical circuit under the conditions ofload which they are rated.

TYPE OF SWITCH ACCORDINGTO VOLTAGESwitches are rated as 250V, 600V,or 5KVas required.

TYPE OF SWITCH ACCORDINGTO INTENSITY OF USE

1. Normal Duty (ND) intended fornormal use in light and power circuitsas in general-purpose switches.

2. Heavy Duty (HD) intended forfrequent interrupting.

3. Light Duty (LD)intended to connectthe loads occasionally, such as serviceswitches.


25/51

7/14/20

2

TYPE OF SWITCH - ACCORDINGTO TYPE OF SERVICE

1. Service Switch intended todisconnect all the electric service inthe building except emergencyequipment. This may comprise one tosix properly rated switches that areassembled into a switchboard.

2. Power Switches

a) Generalpurpose switches areintended for use in generaldistribution and branch circuits.

b) Disconnecting or isolating switchesare intended for disconnecting orisolating circuits; used for circuitsrated at more than 600 volts.

a) Generalpurpose switches aresingle-pole or double-pole switchesfor the general purpose use ofconnecting or cutting-off circuits forthe control of lamps or other loadsfrom a single point.

b) Three-way switches are usedwhere it is desired to control lampsfrom two different points, as in astairwell.

c) Four-way switches are used inconjunction with two 3-wire switcheswhere it is desired to control lampsfrom three or more desired points.

3. Wiring Switches include all therelatively small switches that areemployed in interior wiringinstallations for the control ofbranch circuits, individual lamps orappliances.

d) Electrolier or multi-circuit switchesare used for the control of lights inmulti-lamp fixtures so that onelamp or set of lamps may be turnedon alone or in combination withother lamps.

e) Momentary contact switches areused where it is desired to connector cut-off a circuit for only a shortduration. The switch is providedwith a spring so that it will return toits original position as soon as the

handle or button is released.

f) Dimmer switches a rheostat[1] orsimilar device for regulating theintensity of an electric light withoutappreciably affecting spatialdistribution. Also called a dimmer.Wiring switches may either be theflush type, surface type or thependant type.

TYPE OF SWITCH - ACCORDING TO

OPERATION MECHANISMWiring switches may also be classified

according to the operating mechanismas:

1. Rotary switch2. Push-button switch3. Toggle or tumbler switch

TYPE OF SWITCH - ACCORDING TONUMBER OF POLES AND THROWS

1. Poles that part of the switch which isused for making or breaking of aconnection and which is electricallyinsulated from other contact making orbreaking parts.

2. Throws - a single throw switch is onewhich will make a closed circuit onlywhen the switch is thrown in oneposition. A double throw switch willmake a closed circuit when thrown ineither of two positions.


26/51

7/14/20

2

SPECIAL SWITCHES

1. Time Controlled Switches Thisdevice comprises a precision low

speed miniature drive motor (timer)to which some type of electriccontact-making device is connected.

2. Remote Control (RC) Switches Acontactor[1], or more specifically, arelay[2], that latches after beingoperated wireless from a distance.

3.Air Switch a switch in which theinterruption of a circuit occurs in air.

4. Knife Switch a form of air switch inwhich a hinged copper bladeis placed between twocontact clips.

5. Float Switch a switch controlled bya conductor floating in a liquid.

6. Mercury Switch an especially quietswitch that opens and closes an electriccircuit by shifting a sealed glass tube ofmercury so as to uncover or cover thecontacts.

7. Key Switch a switch operated onlyby inserting a key or a card. Also calleda card switch.

8. Automatic Transfer Switch (ATS)This device, an essential part of anemergency or standby service, isbasically a double throw switch,generally 3-pole, so arranged that onfailure of normal power, emergencyservice is automatically supplied.

3.7 WALL PLATES OR FACEPLATES -These are coverings for switches and walloutlets usually made of metal or ofphenollic compound (Bakelite).


27/51

7/14/20

2

3.8 OVER-CURRENT CIRCUITPROTECTIVE DEVICES are deviceswhose sole purpose is to protect

insulation, wiring, switches and otherapparatus from overheating or burning,due to overloads, to faults or to shortcircuits, by automatically cutting off thecircuit.

FUSE is a device consisting of analloy link of wire with a low meltingtemperature which is inserted in thecircuit, in such a way, that all current

which passes through the circuit, mustalso pass through this metal.

CIRCUIT BREAKERS is an over-current protective device designed tofunction as a switch, or it can bemanually tripped and thus act as acircuit switch. It breaks a circuit with anautomatic tripping device without injuryto itself.

GROUND FAULT CIRCUITINTERRUPTERS (GFCI or GFI) isan over current protective device thatwill provide ground fault protection aswell as function as an ordinary circuitbreaker.


28/51

7/14/20

2

PANELBOARDS popularly known aspanel or electrical panel, it is simplythe box wherein the protective devises arehoused from which the circuits and bus

bars terminate.

SWITCHBOARDS are free standingassemblies of switches, fuses, and/orcircuit breakers whose function normallyis to provide switching and feederprotection to a number of circuitsconnected to a main source.

UNIT SUBSTATIONS (Transfer Load

Centers) an assembly of primary switch-fuse-breaker, step-down transformer,meters, controls, bus bars and secondaryswitchboard. It is used to supply powerfrom a primary voltage line to any largefacility.

4.1 WIRING METHODS

KNOB AND TUBE WIRING anobsolete wiring system consisting ofsingle insulated conductors secured toand supported on porcelain knobs andtubes. When wires run through walls,they are inserted into a nonmetallic fire-resistant tubing called a loom.

RIGID METAL CONDUIT WIRINGis the best and most expensive amongthe usual type of wiring. Its advantagesare:1. it is fireproof;2. moisture proof;3. it is mechanically strong so that nailscannot be driven through it and it is notreadily deformed by blows;4. it resists the normal action of cementwhen embedded in concrete or masonry.

4. WIRING SYSTEMS


29/51

7/14/20

2

FLEXIBLE METAL CONDUITWIRING Its installation is mucheasier and quicker than that of rigidmetal conduits. Unlike the rigid conduits

which come in short lengths of 10 ft. (3M), flexible metal conduit wiring comesin length of 25 ft 250 ft (8 M 83 M)depending on the size of the conduit.

ARMORED CABLE WIRING (BXWIRING) consists of rubber orthermoplastic covered wire protectedfrom injury to a certain extent fromdampness by one or two layers of flexiblesteel armor.

SURFACE METAL RACEWAYWIRING the wires are supported on a

thin sheet steel casing. The raceway isinstalled exposed, being mounted on thewalls or ceiling. Metal raceways must becontinuous from outlet to outlet or

junction box, designed especially for usewith metal raceways.

FLAT CABLE ASSEMBLIES a fieldinstalled rigidly mounted squarestructural channel (15/8 standard)designed to carry 2 to 4 conductors (No.10 AWG) and will act as light duty(branch circuit) plug-in busways.

LIGHTING TRACK a factory-assembled channel with conductors forone to four circuits permanentlyinstalled in the track that will act aslight duty (branch circuit) plug-in

busways.

CABLE TRAY / OPEN RACEWAY is a continuous open support forapproved cables. When used as ageneral wiring system, the cablesmust be self-protected, jacketedtypes, type TC.


30/51

7/14/20

3

FLOOR RACEWAYS The NECrecognizes three types of floorraceways:

1. Underfloor Ducts (UF) installed beneath

or flush with the floor. These underfloorducts usually requires a triple ductsystem for power, telephone andsignal cabling.

2. Cellular Metal Floor Raceway Foundusually in office landscaping, it is anintegrated structural/electrical systemin a cellular metal floor.

3. Precast Cellular Concrete made ofconcrete cells fed from header ducts,which are normally installed in concretefill above the hollow core structural slabor fed from the ceiling void below. Thecells can be used for air distribution andfor piping.

CEILING RACEWAY SYSTEMS under-the-ceiling raceways composed ofheader ducts and distribution ductsseparate for power and telephone cabling.They permit very rapid changes in layoutsat low cost and are therefore particularlydesirable in stores where frequent displaytransformations necessitate correspondingelectrical facility adjustments.

PRE-WIRED CEILING DISTRIBUTIONSYSTEMS are ceiling raceways that arepre-wired in the factory and plugged inwhere required.


31/51

7/14/20

3

FEEDER

BRANCH CIRCUIT-CEILING/WALL

BRANCH CIRCUIT-FLOOR

3&4 WIRES CIRCUIT NO.MARK INDICATES 2 WIRES

CROSSING WIRES

CONNECTING WIRES

LIGHTING OUTLET CEILING

RECESSED CEILING OUTLETDASH INDICATES SHAPE OFFIXTURE

LIGHTING OUTLET WALL

FLUORESCENT LAMP

L LAMP HOLDER

PS LAMP HOLDER WITH PULL SWITCH

C

D

CLOCK OUTLET

DROP CORD OUTLET

F FAN OUTLET

R RADIO OUTLET

FLOOR OUTLET

CONVENIENCE OUTLET SPLIT-WIRED

DUPLEX CONVENIENCE OUTLET

WEATHER PROOF OUTLETWP

SOUTLET AND SWITCH

RRANGE OUTLET

SPECIAL PURPOSE OUTLET

refREFRIGERATOR OUTLET

PUSH BUTTON

BELL

BUZZER

CHIMECH

ANNUNCIATOR

LIGHTING PANEL

POWER PANEL

FUSE

WH WATT-HOUR METER

T TRANSFORMER

J JUNCTION BOX

GROUND

ELECTRICAL SYMBOLS

LIGHTING LAYOUT PLAN


32/51

7/14/20

3

POWER LAYOUT PLAN

ELECTRICAL REGULATIONSBY PD 1096

1. General Locational Requirements in Towns,Subdivisions, Human Settlements, Industrial Estatesand the like.

Overhead transmission and/or distributionlines/systems including transformers, poles, towers andthe like shall be located and installed following thelatest standards of design, construction andmaintenance but so as not to cause visual pollution andin the interest of public safety, convenience, goodviewing and aesthetics, these may be located alongalleys or back streets.


33/51

7/14/20

3

2. Location of Poles and Clearances of Power Lines along Public Roads.

2.1 All poles erected on public roads shall be covered by Approved PoleLocation (APL) plan from the Municipal Engineer.

2.2 Poles and transformer supports shall be located not more than500mm inside from the road right-of-way or property line, andshall not obstruct the sidewalk, pedestrian path and/or the roaddrainage canal or structure, existing or proposed.

500 mm

Property line

Pole

2.3 Primary lines shall have a minimum vertical clearance of 10 mfrom the crown of the pavement when crossing the highwayand 7.5 m from the top of the shoulder or sidewalkwhen installedalong the side of the highway or street in a highly urbanized area.

10 m7.5 m

2.4 Secondary, neutral and service lines shall have a minimum verticalclearance of 7.5 m from the crown of the road pavement whencrossing the highway and from the top of the shoulder or sidewalkwhen installed along the side of the highway or street in highlyurbanized area.


34/51


35/51

7/14/20

3

4. Open Supply Conductors Attached to Buildings

Where the permanent attachment of open supply conductors of any class tobuildings is necessary for an entrance such conductors shall meet the followingrequirements:

4.1 Conductors of more than 300 volts to ground shall not be carried along ornear the surface of the buildings unless they are guarded or madeinaccessible.

4.2 To promote safety to the general public and to employees not authorizedto approach conductors and other current-carrying parts of electric supplylines, such parts shall be arranged so as to provide adequate clearancefrom the ground or other space generally accessible, or shall be providedwith guards so as to isolate them effectively from accidental contact bysuch persons.

4.3 Undergrounded metal-sheathed service cables, service conduits, metalfixtures and similar noncurrent-carrying parts, if located in urban districtsand where liable to become charged to more than 300 volts to ground,shall be isolated or guarded so as not to be exposed to accidental contactby unauthorized persons. As an alternative to isolation or guarding,noncurrent-carrying parts shall be solidly or effectively grounded.

4.4 Clearance of wires from building surface shall be not less thanthose required Table II.

4.5 Supports over buildings. Service-drop conductors passing over aroof shall be securely supported by substantial structures.Where practicable, such supports shall be independent of thebuilding.

Voltage of Supply

Conductors

Horizontal

Clearance in

Meters

Vertical Clearance

in Meters

300 to 8,700 volts 1.0 2.5

8,700 to 15,000

volts

2.5 2.5

15,000 to 50,000

volts

3.0 3.0

> 50,000 volts 3.0 + 10 mm per Kv

in excess

3.0 + 10 mm per Kv

in excess


36/51

7/14/20

3

5. Conductors Passing By or Over Buildings

5.1 Minimum Clearances. Unguarded or accessible supply conductors

carrying voltages in excess of 300 volts may be run either besideor over buildings. The vertical or horizontal clearance to anybuilding or its attachments (balconies, platforms, etc.) shall be aslisted below. The horizontal clearance governs above the rooflevel to the point where the diagonal equals the vertical clearancerequirement. This rule should not be interpreted as restricting theinstallation of a trolley contact conductor over the approximatecenter line of the track it serves.

5.2 Guarding of Supply Conductors/Supply of Conductors of 300 voltsor more shall be properly guarded by grounded conduit, barriers,or otherwise, under the following conditions:

1. Where the clearances set forth in Table II above cannotbe obtained.

2. Where such supply conductors are placed near enough towindows, verandas, fire escapes, or other ordinarilyaccessible places within the reach of persons.

5.3 Where the required clearances cannot be obtained, supplyconductors shall be of Grounded Metallic Shield, Jacketed PrimaryCables grouped or bundled and supported by grounded messengerwires.

V-

V


37/51

7/14/20

3

Clearance of line

conductors from -

Communication LInes Supply LInes

In general On jointly used

poles

In general (0 to

8700 volts)

On jointly used

poles (0 to 8700

volts)

Exceeding 8700

volts, add for each

1000 volts of excess

Vertical and lateral

conductors of the

same circuit

75 mm 75 mm 75 mm 75 mm 6.25 mm

Vertical and lateral

conductors of other

circuits

75 mm 75 mm 150 mm 150 mm 10 mm

Span and guy wires

attached to same

pole: general

75 mm 150 mm 150 mm 150 mm 10 mm

Span and guy wires

attached to same

pole: when parallel

to line

75 mm 150 mm 300 mm 300 mm 10 mm

Lightning protection

wires parallel to line:

surfaces of crossarms

75 mm 75 mm 75 mm 75 mm 5 mm

Lightning protection

wires parallel to line:

surfaces of poles

75 mm 125 mm 75 mm 125 mm 5 mm

6. Clearance of Service Drops

6.1 Service drop conductors shall not be readily accessible and when not inexcess of 600 volts, shall conform to the following:

a. Clearances over roof. Conductors shall have a clearance of not lessthan 2.5m from the highest point of roofs over which they pass withthe following exceptions:

2.5 m

Highest point

Service Drop Conductor< 600 volts


38/51

7/14/20

3

Exception No. 1. Where the voltage between conductors does not exceed 300volts and the roof has a slope of not less than 100mm in 300mm, theclearance may not be less than 1m.

1 m

Highest point

Service Drop Conductor300 volts

Slope 1:3

Exception No. 2. Service drop conductors of 300 volts or less which do not passover other than a maximum of 1.2m of the overhang portion of the roof for thepurpose of terminating at a through-the-roof service raceway or approvedsupport may be maintained at a minimum of 500mm from any portion of theroof over which they pass.

1.2 m

Highest point

Service Drop Conductor 300 volts

500mm


39/51

7/14/20

3

6.2 Clearance from the Ground. Conductors shall have a clearance of not lessthan 3m from the ground or from any platform or projection from which theymight be reached.

conductor

platform 3 m

6.3 Clearance from Building Openings. Conductors shall have a horizontalclearance of not less than 1m from windows, doors, porches, fire escapes, orsimilar locations and shall be run at least 500mm above the top level of awindow or opening.

window

500mm

1 m

6.4 Service Drop of communication lines, when crossing a street, shall have aclearance of not less than 5.5 m from the crown of the street or sidewalkover which it passes.

5.50 m 5.50 m

Service drop of communication line

Service Drop of communication lines shall have a minimum clearance of 3mabove ground at its point of attachment to the building or pedestal.

3mprotector

3m


40/51

7/14/20

4

6.5 No parts of swimming and wading pools shall be placed under existing servicedrop conductors or any other over-head wiring; nor shall such wiring beinstalled above the following:

a. Swimming and wading pools and the area extending 3m

outward horizontally from the inside of the walls of the pool.b. Diving Structuresc. Observation stands, towers or platforms

Swimming pool

Servicedropconductor

3 m

7. Wiring Methods

Service entrance conductors extending along the exterior or enteringbuildings or other structures shall be installed in rigid steel conduit orasbestos cement conduit or concrete encased plastic conduit from point ofservice drop to meter socket and from meter socket to the disconnectingequipment. However, where the service entrance conductors are protectedby approved fuses or breakers at their outer ends (immediately after theservice drop or lateral) they may be installed in any of the recognized wiringmethods.

7.1 Abandoned Lines and/or portions of lines no longer required to provideshall be removed.

7.2 Power or communication poles, lines, service drops and other lineequipment shall be free from any attachment for antennas, signs,streamers and the like.

7.3 Metallic sheaths or jackets of overhead power or communication cablesshall be grounded at a point as close as possible to ground levelwhenever such cables change from overhead to undergroundinstallations.


41/51

7/14/20

4

8. Transformers

8.1 Oil-insulated Transformers Installed Outdoors. Combustible material,combustible buildings and parts of buildings, fire escapes, door andwindow openings shall be safeguarded from fires originating in oil-

insulated transformers installed on, attached to, or adjacent to a buildingor combustible material. Space separations, fire-resistant barriers andenclosures which confine the oil of a ruptured transformer tank arerecognized safeguards. One or more of these safeguards shall be appliedaccording to the degree of hazard involved in cases where the transformerinstallation presents a fire hazard. Oil enclosures may consist of fire-resistant dikes, curbed areas or basins, or trenches filled with coarse,crushed stone. Oil enclosures shall be provided with trapped drains incases where the exposure and the quantity of oil involved are such thatremoval of oil is important.

Trench allaround

Exterior Oil-insulatedTransformer

8.2 Dry-Type Transformers Installed Indoors. Transformers rated 112-1/2 KVAor less shall have separation of at least 300mm from combustible materialunless separated there from by a fire-resistant heat-insulating barrier orunless of a rating not exceeding 600 volts and completely enclosed except forventilating openings.

Dry-type transformer112-1/2 Kva or less

300mm

Combustible Wall


42/51

7/14/20

4

8.3 Askarel-Insulated Transformers Installed Indoors. Askarel-insulatedtransformers rated in excess of 25 KVA shall be furnished with a pressurerelief vent. Where installed in a poorly ventilated place they shall befurnished with a means for absorbing any gases generated by arcing insidethe case, or the pressure relief vent shall be connected to a chimney or fluewhich will carry such gases outside the building. Askarel-insulatedtransformers rated more than 35,000 volts shall be installed in a vault.

Transformers of more than 112-1/2 KVA rating shall be installed in a transformerroom of fire-resistant construction unless they are constructed with Class B (80Crise) or Class H (150C rise) insulation, and are separated from combustiblematerial not less than 1.85m horizontally and 3.7m vertically or are separatedthere from by a fire-resistant heat-insulating barrier.

Transformers rated more than 35,000 volts shall be installed in a vault.

Dry-type transformer112-1/2 Kva or less

1.85 m

CombustibleWall

Combustible ceiling

3.70 m

vault

Transformer morethan 35,000 volts

8.4 Oil-Insulated Transformers Installed Indoors. Oil-insulated transformers shall

be installed in a vault constructed as specified in this Section except as follows:

1. NOT OVER 112-1/2KVATOTAL CAPACITY. The provisions for transformervaults specified in Section 9.3 of this Rule apply except that the vault maybe constructed of reinforced concrete not less than 100mm thick.

2. NOT OVER 600 VOLTS. A vault is not required provided suitablearrangements are made where necessary to prevent a transformer oil fireigniting other materials, and the total transformer capacity in one locationdoes not exceed 10 KVA in a section of the building classified ascombustible, or 75 KVA where the surrounding structures is classified asfire-resistant construction.

> 100mm thick reinforcedconcrete vault

oil insulated transformer< 112-1/2 KVa


43/51

7/14/20

4

8.5 Guarding. Transformers shall be guarded as follows:

1. MECHANICAL PROTECTION. Appropriate provisions shall be madeto minimize the possibility of damage to transformers from externalcauses where the transformers are located exposed to physicaldamage.

2. CASE OR ENCLOSURE. Dry-type transformers shall be provided witha non-combustible moisture resistant case or enclosure which will

provide reasonable protection against accidental insertion of foreignobjects.

3. EXPOSED LIVE PARTS. The transformer installation shall conformwith the provisions for guarding of live parts in PEC Rule 1056.

4. VOLTAGE WARNING. The operating voltage of exposed live parts oftransformer installations shall be indicated by signs or visiblemarkings on the equipment or structures.

3. FURNACE TRANSFORMERS. Electric furnace transformers of a total ratingnot exceeding 75 KVA may be installed without a vault in a building or roomof fire-resistant construction provided suitable arrangements are made toprevent a transformer oil fire spreading to other combustible material.

4. DETACHED BUILDING. Transformers may be installed in a building whichdoes not conform with the provisions specified in this Code for transformervault, provided neither the building nor its contents present fire hazard toany other building or property, and provided the building is used only insupplying electric service and the interior is accessible only to qualifiedpersons.

9. Provisions for Transformer Vaults

9.1 New Building. New buildings requiring an expected load demand of200KVA or above shall be provided with a transformer vault, except thattransformers may be mounted on poles or structures within the property ifenough space is available, provided that all clearances required can beobtained and no troublesome contamination on insulators, bushings, etc.can cause hazards and malfunctioning of the equipment.

150 mm for R.C200 mm for Brick300 mm for Load bearing CHB

200 Kva or moreWall:

20 mm thick plaster2-1/2 hours fire rating

Floor:100mm thick2-1/2 hours fire rating


44/51

7/14/20

4

9.2 Location. Transformer and transformer vaults shall be readily accessible toqualified personnel for inspection and maintenance. Vaults shall be locatedwhere they can be ventilated to the outside air without using flues or ductswherever such an arrangement is practicable.

9.3 Walls, Roof and Floor. The walls and roofs of vaults shall consist of reinforcedconcrete not less than 150mm thick, masonry or brick not less than 200mmthick, or 300mm load bearing hollow concrete blocks. The inside wall and roofsurface of vaults constructed of hollow concrete blocks shall have a coating ofcement or gypsum plaster not less than 20mm thick. The vault shall have aconcrete floor not less than 100mm thick. Building walls and floor which meetthese requirements may serve for the floor, roof and one or more walls of thevaults. Other forms of fire-resistive construction are also acceptable providedthey have adequate structural strength for the conditions and a minimum fireresistance of two and one half hours according to the approved Fire TestStandard. The quality of the material used in the construction of the vault shallbe of the grade approved by the Building Official having jurisdiction.

9.4 Doorways. Any doorway leading from the vault into the building shall be

protected as follows:

1. TYPE OF DOOR. Each doorway shall be provided with a tight-fittingdoor of a type approved for openings in such locations by the authorityenforcing this Code.

2. SILLS. A door sill or curb of sufficient height to confine within thevault, the oil from the largest transformer shall be provided and in nocase shall the height be less than 100mm.

3. LOCKS. Entrance doors shall be equipped with locks, and doors shallbe kept locked, access being allowed only to qualified persons. Locks

and latches shall be so arranged that the door may be readily andquickly opened from the inside.

10.Ventilation. Ventilation shall be adequate to prevent a transformer temperaturein excess of the prescribed values.

1. LOCATION. Ventilation openings shall be located as far away aspossible from doors, windows, fire escapes and combustible material.


45/51

7/14/20

4

2. ARRANGEMENT. Vaults ventilated by natural circulation of air may haveroughly half of the total area of openings required or ventilation in one or moreopenings near the floor and the remainder in one or more openings in the roofor in the sidewalls near the roof; or all of the area required for ventilation may

be provided in one or more openings in or near the roof.

3. SIZE. In the case of vaults ventilated to an outdoor area without using ducts orflues the combined net area of all ventilating openings after deducting the areaoccupied by screens, grating, or louvers, shall be not less than 0.006 sqmm perKVA of transformer capacity in service, except that the net area shall be notless than 0.1 sqm for any capacity under 50 KVA.

4. COVERING. Ventilation openings shall be covered with durable gratings,screens, or louvers, according to the treatment requirement required in order toavoid unsafe conditions.

5. DAMPERS. Where automatic dampers are used in the ventilation openings of

vaults containing oil-insulated transformers, the actuating device should bemade to function at a temperature resulting from fire and not a temperaturewhich might prevail as a result of an overheated transformer or bank oftransformers. Automatic dampers should be designed and constructed tominimize the possibility of accidental closing.

6. DUCTS. Ventilating ducts shall be constructed of fire resistant material.

7. DRAINAGE. Where practicable, vaults containing more than 100KVAtransformer capacity shall be provided with a drain or other means which willcarry off any accumulation of oil or water in the vaults unless local conditionsmake this impracticable.

8. WATER PIPES AND ACCESSORIES. Any pipe or duct system foreign to theelectrical installation should not enter or pass through a transformer vault.Where the presence of such foreign system cannot be avoided, appurtenancesthereto which require maintenance at regular intervals shall not be locatedinside the vault. Arrangements shall be made where necessary to avoid

possible trouble from compensation, leaks and breaks in such foreign system.Piping or other facilities provided for fire protection or for water-cooledtransformers are not deemed to be foreign to the electrical installation.


46/51

7/14/20

4

11.Capacitors.

1. Application. This section applies to installation of capacitors on electriccircuits in or on buildings.Exception No. 1. Capacitors that are components of other apparatus shall

conform to the requirements for such apparatus.Exception No. 2. Capacitors in hazardous locations shall comply withadditional requirements in PEC Section 400-415.

2. Location. An installation of capacitors in which any single unit containsmore than three gallons of combustible liquid shall be in a vault conformingto part C of PEC Section 319.

3. Mechanical Protection. Capacitors shall be protected from physical damageby location or by suitable fences, barriers or other enclosures.

4. Cases and Supports. Capacitors shall be protected from physical damage bylocation or by suitable fences, barriers or other enclosures.

5. Transformers Used with Capacitors. Transformers which are components ofcapacitor installations and are used for the purpose of connecting thecapacitor to a power circuit shall be installed in accordance with PEC Section319. The KVA rating shall not be less than 135 per cent of the capacitorrating in Kva.

12.Emergency Systems

1. The provisions of this Section shall apply to the installation, operation andmaintenance of circuits, systems and equipment intended to supplyillumination and power in the event of failure of the normal supply or in theevent of accident to elements of a system supplying power and illuminationessential for safety to life and proper where such systems or circuits arerequired by the Fire Code, or by any government agency having jurisdiction.

Emergency systems are generally installed in places of assembly whereartificial illumination is required, such as buildings subject to occupancy bylarge numbers of persons, hotels, theaters, sports arenas, hospitals and similarinstitutions. Emergency systems provide power for such functions as

refrigeration, operation of mechanical breathing apparatus, ventilationessential to maintain life, illumination and power for hospital room, fire alarmsystems, fire pumps, industrial processes where current interruption wouldproduce serious hazards, public address systems and other similar functions.

2. All requirements of this Section shall apply to emergency systems.

3. All equipment for use on emergency systems shall be properly approved.


47/51

7/14/20

4

4. Tests and Maintenance

a. The authority having jurisdiction shall conduct or witness a test on thecomplete system upon completion of installation, and periodically afterwards.

b. Systems shall be tested periodically in accordance with a schedule acceptableto the authority having jurisdiction to assure that they are maintained in properoperating condition.

c. Where the battery systems or unit equipment are involved, includingbatteries used for starting or ignition in auxiliary engines, the authority having

jurisdiction shall require periodic maintenance.

d. A written record shall be kept of such tests and maintenance.

5. Emergency systems shall have adequate capacity and rating for the emergencyoperation of all equipment connected to the system.

6. Current supply shall be such that in the event of failure of the normal supply toor within the building or group of buildings concerned, emergency lighting oremergency power, will be immediately available. The supply system foremergency purposes may be composed one or more of the types of systemscovered in Section 12.7 to Section 12.10 of this Rule. Unit equipment inaccordance with Section 12.21 shall satisfy the applicable requirements of thisSection.

Consideration must be given to the type of service to be rendered; whether forshort duration, as for exit lights of a theater, or for long duration, as forsupplying emergency power and lighting during long periods of current failurefrom trouble either inside or outside the buildings, as in the case of a hospital.

Assignment of degree of reliability of the recognized emergency supply systemdepends upon the careful evaluation of the variables of each particularinstallation.

7. A storage battery of suitable rating and capacity shall supply, by means of aservice installed according to Section 200 of the PEC and maintained at notmore than 90 per cent of system voltage, the total load of the circuits supplyingemergency lighting and emergency power for a period of at least hour.


48/51

7/14/20

4

8. A generator set driven by some form of prime mover, with sufficient capacityand proper rating to supply circuits carrying emergency lighting or lighting andpower, equipped with suitable means for automatically starting the prime mover

on failure of the normal service shall be provided. For hospitals, the transition-time from instant of failure of the normal power source to the emergencygenerator source shall not exceed ten seconds. (See Section 12.4)

9. There shall be two services, each in accordance with Section 200 of the PEC,widely separated electrically and physically to minimize the possibility ofsimultaneous interruption of power supply arising from an occurrence withinthe building or group of buildings served.

10.Connections on the line side of the main service shall be sufficiently separatedfrom said main service to prevent simultaneous interruption of supply throughan occurrence within the building or group of buildings served.

11. The requirements of Section 12.5 and Section 12.6 also apply to installationswhere the entire electrical load on a service or sub-service is arranged to besupplied from a second source. Current supply from a standby power plantshall satisfy the requirements of availability in Section 12.6.

12.Audible and visual signal devices shall be provided, where practicable, for thefollowing purposes:

a. To give warning of dearrangement of the emergency or auxiliary source.

b. To indicate that the battery or generator set is carrying a load.

c. To indicate when a battery charger is properly functioning.

13. Only appliances and lamps specified as required for emergency use shall besupplied by emergency lighting circuits.

14. Emergency illumination shall be provided for all required exit lights and allother lights specified as necessary for sufficient illumination.Emergency lighting systems should be so designed and installed that thefailure of any individual lighting element, such as the burning out of a lightbulb, shall not leave any area in total darkness.


49/51

7/14/20

4

15.Branch circuits intended to supply emergency lighting shall be so installed as toprovide service immediately when the normal supply for lighting is interrupted.Such installations shall provide either one of the following:

a. An emergency lighting supply, independent of the general lightingsystem with provisions for automatically transferring to the emergencylights by means of devices approved for the purpose upon the event offailure of the general lighting system supply.

b. Two or more separate and complete systems with independent powersupply, each system providing sufficient current for emergency lightingpurposes. Unless both systems are used for regular lighting purposesand are both lighted, means shall be provided for automaticallyenergizing either system upon failure of the other. Either or bothsystems may be part of the general lighting system of the protectedoccupancy if circuits supplying lights for emergency illumination areinstalled in accordance with other Section of this Rule.

16. For branch circuits which supply equipment classed as emergency, there shallbe an emergency supply source to which the load will be transferredautomatically and immediately upon the failure of the normal supply.

17. Emergency circuit wiring shall be kept entirely independent of all other wiring and

equipment and shall not enter the same raceway, box or cabinet with other wiringexcept:

a. In transfer switches, orb. In exit or emergency lighting fixtures supplied from two (2) sources.

18. The switches installed in emergency lighting circuits shall be so arranged that onlyauthorized persons have control of emergency lighting, except:

a. Where two or more single throw switches are connected in parallel tocontrol a single circuit, at least one of those switches shall be accessibleonly to authorized persons.

b. Additional switches which act only to put emergency lights into operationbut not to disconnect them may be permitted.

Switches connected in series and three- and four-way switches shall not beallowed.

19. All manual switches for controlling emergency circuits shall be located at the mostaccessible place to authorized persons responsible for their actuation. In places ofassembly, such as theaters, a switch for controlling emergency lighting systemsshall be located in the lobby or at a place conveniently accessible there from.In no case shall a control switch for emergency lighting in a theater for motionpicture projection be placed in the projection booth or on the stage. However,where multiple switches are provided, one such switch may be installed in suchlocations and so arranged that it can energize but not disconnect for the circuit.


50/51

7/14/20

5

20. Lights on the exterior of the building which are not required for illuminationwhen there is sufficient daylight may be controlled by an automatic lightactuated device approved for the purpose.

21. In hospital corridors, switching arrangements to transfer corridor lighting inpatient areas of hospitals from overhead fixtures to fixtures designed to providenight lighting maybe permitted, provided that the switching system is sodesigned that switches can only select between two sets of fixtures but cannotextinguish both sets at the same time.

22.The branch circuits over current devices in emergency circuits shall beaccessible to authorized persons only.

23. Where permitted by the authority having jurisdiction, in lieu of other methodsspecified elsewhere in this Section, individual unit equipment for emergencyillumination shall consist of:

a. Batteryb. Battery charging means, when a storage battery is usedc. One or more lamps, andd. A relaying device arranged to energize the lamps automatically upon

failure of the normal supply to the building

The batteries shall be of suitable rating and capacity to supply and maintain, at not

less than 90 per cent of rated lamp voltage, the total lamp load associated with theunit for a period of at least hour. Storage batteries, whether of the acid or alkalitype, shall be designed and constructed to meet the requirements of emergencyservice. Lead-acid type storage batteries shall have transparent jars.

Unit equipment shall be permanently fixed in place and shall have all wiring to eachunit installed in accordance with the requirements of any of the wiring methodsdiscussed in Chapter II of the PEC. They shall not be connected by flexible cord. Thesupply circuit between the unit equipment and the service, the feeders or the branchcircuit wiring shall be installed as required by Section 12.17. Emergency illuminationfixtures which obtain power from a unit equipment which are not part of the unitequipment shall be wired to the unit equipment as required by Rule 5257 of the PECand in accordance with the one of the wiring methods described in Chapter II of the

PEC.

13. Effectivity

1. All primary and secondary supply lines already existing shall comply with theprovisions of this Rule within two (2) years from the effectivity of this Rule.2. Transformers to be installed on, attached to, or in buildings shall comply with therequirements of this Rule. Transformer installations already existing shall comply withthe requirements within two (2) years from the effectivity of this Rule.3. Non-compliance with the provisions of this Rule shall be subject to the penalprovisions in Section 213 of PD 1096.


51/51

7/14/20

THANK YOU

Documents

1 Electrical Systems Final